POS-122-1113

W.E.ST. Elektronik GmbH 

Technical Documentation 

POS-122-A 

POS-122-I 

POS-122-P 

Positioning module


CONTENTS 

1 General Information .............................................................................................................................................. 4 

1.1 Order number ............................................................................................................................................... 4 

1.2 Scope of supply ............................................................................................................................................ 4 

1.3 Accessories .................................................................................................................................................. 4 

1.4 Symbols used ............................................................................................................................................... 5 

1.5 Using this documentation ............................................................................................................................. 5 

1.6 Legal notice .................................................................................................................................................. 5 

1.7 Safety instructions ........................................................................................................................................ 6 

2 Characteristics ...................................................................................................................................................... 7 

2.1 Device description ........................................................................................................................................ 8 

3 Use and application .............................................................................................................................................. 9 

3.1 Installation instructions ................................................................................................................................. 9 

3.2 Typical system structure ............................................................................................................................. 10 

3.3 Method of operation .................................................................................................................................... 11 

3.4 Commissioning ........................................................................................................................................... 12 

4 Technical description .......................................................................................................................................... 13 

4.1 Input and output signals ............................................................................................................................. 13 

4.2 LED definitions ........................................................................................................................................... 14 

4.3 Circuit diagram ........................................................................................................................................... 15 

4.4 Typical cabling ............................................................................................................................................ 16 

4.5 Technical data ............................................................................................................................................ 17 

5 Parameters ......................................................................................................................................................... 18 

5.1 Parameter overview .................................................................................................................................... 18 

5.2 Parameter description ................................................................................................................................ 19 

5.2.1 S (Presetting command values) ......................................................................................................... 19 

5.2.2 VC (Presetting velocities) ................................................................................................................... 19 

5.2.3 DSEL (Deactivation of the S-VALID) ................................................................................................. 20 

5.2.4 A (Acceleration time).......................................................................................................................... 20 

5.2.5 D (Deceleration /braking distance) ..................................................................................................... 20 

5.2.6 CTRL (Deceleration function characteristic) ...................................................................................... 21 

5.2.7 VMODE (Switching over the control mode) ....................................................................................... 22 

5.2.8 TH (Stroke time for speed controlled axis ) ........................................................................................ 22 

5.2.9 HAND (Manual speed) ....................................................................................................................... 22 

5.2.10 MIN (Deadband compensation) ......................................................................................................... 23 

5.2.11 MAX (Limitation / Gain ) ..................................................................................................................... 23 

5.2.12 TRIGGER (Response threshold for the MIN parameter) ................................................................... 23 

5.2.13 INPOS (In position window) ............................................................................................................... 24 

5.2.14 OFFSET (Zero correction) ................................................................................................................. 24 

5.2.15 POL (Output polarity) ......................................................................................................................... 24 

5.2.16 SENS (Module monitoring) ................................................................................................................ 25 

5.2.17 DIN (Input status) ............................................................................................................................... 25 

5.2.18 PROCESS DATA (Monitoring) ........................................................................................................... 25 

6 Appendix ............................................................................................................................................................ 26 

6.1 Failure monitoring ....................................................................................................................................... 26 

6.2 Troubleshooting .......................................................................................................................................... 26 

6.3 Description of the command structure ........................................................................................................ 28 

7 ADDITIONAL INFORMATION: Power output stage ........................................................................................... 29 

7.1 General function ......................................................................................................................................... 29 

7.2 Device description ...................................................................................................................................... 30 

7.3 Inputs and outputs ...................................................................................................................................... 31 

Page 2 of 36 POS-122-*-1113 06.06.2012


7.4 Circuit diagram ........................................................................................................................................... 31 

7.5 Typical cabling ........................................................................................................................................... 32 

7.6 Technical data ............................................................................................................................................ 32 

7.7 Parameters ................................................................................................................................................ 33 

7.7.1 Parameter overview .......................................................................................................................... 33 

7.8 Parameter description ................................................................................................................................ 33 

7.8.1 CURRENT (Current range switchover) ............................................................................................. 33 

7.8.2 DFREQ (Dither frequency) ................................................................................................................ 33 

7.8.3 DAMPL (Dither amplitude)................................................................................................................. 33 

7.8.4 PWM (PWM frequency) ..................................................................................................................... 34 

7.8.5 PPWM (Solenoid current controller P element) ................................................................................. 34 

7.8.6 IPWM (Solenoid current controller I element) .................................................................................... 34 

8 Notes.................................................................................................................................................................. 35 


1 General Information 

1.1 Order number 


POS-122-A-1113 1 - with analogue ±10 V differential output and analogue sensor interface 

POS-122-I-1113 - with analogue 4… 20 mA output and analogue sensor interface 

POS-122-P-1113 - (see additional information) with integrated power output stage up to 2,6 A 

1.2 Scope of supply 

To the scope of supply belongs the module including the terminal blocks which are part of the housing. The 

Profibus plug, interface cables and further parts which may be required should be ordered separately. This 

documentation can be downloaded as a PDF file from www.w-e-st.de. 

1.3 Accessories 

RS232-SO - Programming cable with RS232C interface 

USB-SO - Programming cable with USB interface 

WPC-300 - Start-Up-Tool (downloadable – products/software) 

1 The number of the version consists of the hardware-version (first two digits) and the software-version (second two 

digits). Because of the development of the products these numbers can vary. They are not strictly necessary for the 

order. We will always deliver the newest version. 


1.4 Symbols used 

General information 

Safety-related information 

1.5 Using this documentation 

Structure of the documentation: 


The standard product is descibed up to chapter 6. The extensions like POWER STAGE or 

SSI-INTERFACE are described in the chapters ADDITIONAL INFORMATION. 

1.6 Legal notice 

W.E.St. Elektronik GmbH 

Gewerbering 31 

D-41372 Niederkrüchten 

Tel.: +49 (0)2163 577355-0 

Fax.: +49 (0)2163 577355-11 

Home page: www.w-e-st.de or www.west-electronics.com 

EMAIL: info@w-e-st.de 

Date: 06.06.2012 

The data and characteristics described herein serve only to describe the product. The user is required to 

evaluate this data and to check suitability for the particular application. General suitability cannot be 

inferred from this document. We reserve the right to make technical modifications due to further 

development of the product described in this manual. The technical information and dimensions are nonbinding. 

No claims may be made based on them. 

This document is copyright. 


1.7 Safety instructions 


Please read this document and the safety instructions carefully. This document will help to define the 

product area of application and to put it into operation. Additional documents (WPC-300 for the start-up 

software) and knowledge of the application should be taken into account or be available. 

General regulations and laws (depending on the country: e. g. accident prevention and environmental 

protection) must be complied with. 

These modules are designed for hydraulic applications in open or closed-loop control 

circuits. Uncontrolled movements can be caused by device defects (in the hydraulic 

module or the components), application errors and electrical faults. Work on the drive or 

the electronics must only be carried out whilst the equipment is switched off and not under 

pressure. 

This handbook describes the functions and the electrical connections for this electronic 

assembly. All technical documents which pertain to the system must be complied with 

when commissioning. 

This device may only be connected and put into operation by trained specialist staff. The 

instruction manual must be read with care. The installation instructions and the 

commissioning instructions must be followed. Guarantee and liability claims are invalid if 

the instructions are not complied with and/or in case of incorrect installation or 

inappropriate use. 

CAUTION! 

All electronic modules are manufactured to a high quality. Malfunctions due to the failure of 

components cannot, however, be excluded. Despite extensive testing the same also 

applies for the software. If these devices are deployed in safety-relevant applications, 

suitable external measures must be taken to guarantee the necessary safety. The same 

applies for faults which affect safety. No liability can be assumed for possible damage. 

Further instructions 

• The module may only be operated in compliance with the national EMC regulations. It is 

the user’s responsibility to adhere to these regulations. 

• The device is only intended for use in the commercial sector. 

• When not in use the module must be protected from the effects of the weather, 

contamination and mechanical damage. 

• The module may not be used in an explosive environment. 

• To ensure adequate cooling the ventilation slots must not be covered. 

• The device must be disposed of in accordance with national statutory provisions. 


2 Characteristics 


This electronic module is developed for controlling of hydraulic positioning drives. A typical signal accuracy 

of app. 0,01% of the sensor stroke can be achieved. The sampling time of the control loop is 1ms. 

Proportional valves with integrated electronics or external power amplifiers can be controlled by the analogue 

differential output (or by the 4… 20 mA current output). Additionally an integrated power amplifier for 

best performance is available. 

Eight target positions - with the related velocities - can be selected via digital inputs. 

Internal profile generation (acceleration time, max. velocity and stroke depended deceleration) provides 

fast and excellent positioning. Two modes can be selected. 

Stroke depended deceleration: The axis drives in open loop mode and is switched over in closed loop 

during deceleration. This is a time-optimal positioning structure with very high stability. The maximal velocity 

can be limited by the external velocity input. 

NC mode: An integrated NC profile generator (VMODE command) can be activated. The position profile is 

internally generated with defined speed and the axis is following (controlled by the following error) the 

command position with the same speed. 

Internal functions, InPos, out of stroke and sensor or command failure are monitored by the two digital outputs: 

ready and status. 

The adjustment via RS232C is simple and easy to understand. A standard terminal program or our special 

windows application software (WPC-300, download from our homepage) can be used. 

Typical applications: positioning drives, handling axis and fast transportable drives (adaptation of non-linear 

valve characteristics). 

Features 

• Eight selectable target positions / velocities 

• High speed positioning mode 

• Principle of stroke depended deceleration or NC controlled movement (speed controlled) 

• Optimal use of overlapped and zero overlapped proportional valves 

• Internal profile, defined by acceleration time, max velocity and deceleration stroke 

• Programmable speed 

• Simple and application orientated parameter settings 

• Failure monitoring 

• Adjustments via RS232C interface 


2.1 Device description 

99,0000 mm 

Made in Germany 

Date: Add.: 

ID: 

V: 

W.E.ST. Elektronik 


Homepage: http://www.w-e-st.de 

Typenschild und Anschlussbelegung 

Type plate and terminal pin assignment 


LEDs 

RS232C 

Interface 

9 10 11 12 

13 14 15 16 

1 2 3 4 

5 6 7 8 

W.E.ST. 

Page 8 of 36 POS-122-*-1113 06.06.2012 

Ready 

Status 

9 10 11 12 

13 14 15 16 

23,0000 mm 

114,0000 mm 

Klemmblöcke (steckbar) 

Terminals (removable)

3 Use and application 

3.1 Installation instructions 


• This module is designed for installation in a shielded EMC housing (control cabinet). All cables 

which lead outside must be screened; complete screening is required. It is also necessary to avoid 

strong electro-magnetic interference sources being installed nearby when using our open and 

closed loop control modules. 

• Typical installation location: 24 V control signal area (close to PLC) 

The devices must be arranged in the control cabinet so that the power section and the signal 

section are separate from each other. 

Experience shows that the installation place close to the PLC (24 V area) is most suitable. All 

digital and analogue inputs and outputs are fitted with filters and surge absorbers in the device. 

• The module should be installed and wired in accordance with the documentation bearing in mind 

EMC principles. If other consumers are operated with the same power supply, a star-shaped 

ground wiring scheme is recommended. The following points must be observed when wiring: 

• The signal cables must be laid separately from power cables. 

• Analogue signal cables must be screened. 

• All other cables must be screened if there are powerful interference sources (frequency 

converters, power contactors) and cable lengths > 3 m. Inexpensive SMD ferrites can 

be used with high-frequency radiation. 

• The screening should be connected to PE (PE terminal) as close to the module as 

possible. The local requirements for screening must be taken into account in all cases. 

The screening should be connected to at both ends. Equipotential bonding must be 

provided where there are differences between the connected electrical components. 

• If having longer lengths of cable (> 10 m) the diameters and screening measures should 

be checked by specialists (e. g. for possible interference, noise sources and voltage 

drop). Special care is required if using cables of over 40 m in length, and if necessary 

the manufacturer should be consulted if necessary. 

• A low-resistance connection between PE and the mounting rail should be provided. Transient 

interference is transmitted from the module directly to the mounting rail and from there to the local 

earth. 

• Power should be supplied by a regulated power supply unit (typically a PELV system complying 

with IEC364-4-4, secure low voltage). The low internal resistance of regulated power supplies gives 

better interference voltage dissipation, which improves the signal quality of high-resolution sensors 

in particular. Switched inductances (relays and valve coils) which are connected to the same power 

supply must always be provided with appropriate overvoltage protection directly at the coil. 


3.2 Typical system structure 


This minimal system consists of the following components: 

(*1) Proportional valve: the valve type determines the precision. It is expedient to use control valves 

with integrated electronics. 

(*2) Hydraulic cylinder 

(*3) Integrated analogue position sensor (alternatively also with external measurement system) 

(*4) POS-122-A or POS-122-P control module 

(*5) Interface to PLC with analogue and digital signals 


3.3 Method of operation 


This module supports the simple point-to-point positioning with hydraulic drives. The system works with the 

principle of stroke depended deceleration, that means the control gain will be adjusted with the parameters 

D:A and D:B. 

The deceleration characteristics can be defined with the parameter CTRL linear (LIN) or nearly square root 

(SQRT1). By use of standard proportional valves, SQRT1 has to be chosen normally. 

By use of control valves with linear characteristics, it depends on the application. If you choice LIN, a 

shorter deceleration stroke can be set (D:A and D:B). 

Sequence of the positioning: 

The positioning procedure is controlled by the switching inputs. After the release (ENABLE) is applied the 

required position is set the same as the actual position in the module and the drive remains stationary under 

control at the current position. In AUTO mode the module is taking over the selected position (SEL1, 

SEl2 and SEL4) and speed after a signal change (START = low to high) or direcly depending on the parameter 

DSEL. The drive moves directly to the new required position and reports reaching the position via 

the InPos output. 

In manual mode (START disabled) the drive can be moved by means of HAND+ or HAND–. The drive 

moves under open-loop control at the programmed manual speeds. The InPos signal is active during manual 

movement. When the HAND (+ or -) signal is switched off, the current actual position is accepted as the 

required position and the drive comes to a controlled stop. 

Weak points of positioning accuracy: 

Influences on positioning accuracy: 

The positioning accuracy is determined by the hydraulic and mechanical conditions. The right choice of 

valve is therefore a decisive factor. In addition, two mutually contradictory requirements (short position time 

and high accuracy) must be taken into account when designing the system. 

The electronic limitations lie mainly in the resolution of the analogue signals, although with our modules a 

resolution of < 0.01% only needs to be considered with long positions. In addition, the linearity of the individual 

signal points (PLC, sensor and control module) must be considered. The worst-case scenario is that 

a system-specific absolute fault occurs. 

The repeat accuracy is, however, not affected by this. 

V+ 

V+ 

A:A D:A 

D:B 

volumetric flow P-A and B-T 

MAX:A 

control direction 

driving out 

control direction 

driving in 

MAX:B 


A:B

3.4 Commissioning 

Step Task 


Installation Install the device in accordance with the circuit diagram. Ensure it is wired 

correctly and that the signals are well shielded. The device must be installed in a 

metal protective housing (control cabinet or similar). 

Switching on for the first 

time 

Ensure that no unwanted movement is possible in the drive (e. g. switch off the 

hydraulics). Connect an ammeter and check the current consumed by the device. 

If it is higher than specified there is an error in the cabling. Switch the device off 

immediately and check the cabling. 

Setting up communication Once the power input is correct the PC (notebook) should be connected to the 

serial interface. Please see the WPC-300 program documentation for how to set 

up communication. 

Further commissioning and diagnosis are supported by the operating software. 

Pre-parameterization Now set up the following parameters (with reference to the system design and 

circuit diagrams): 

The command values S:x with corresponding speed values VC:x, POLARITY, 

ACCELERATION and DECELERATION. Parameterize specific settings for the 

control element (MIN for deadzone compensation and MAX for maximum 

velocity). 

Pre-parameterization is necessary to minimize the risk of uncontrolled 

movements. 

Control signal Check the control signal with a voltmeter. The control signal (PIN 15 to PIN16) lies 

in the range of ± 10 V. In the current state it should be 0 V. Alternatively, if current 

signals are used, approx. 0 mA should flow. 

Switching on the 

hydraulics 

Activating ENABLE 

The hydraulics can now be switched on. Since the module is not yet generating a 

signal the drive should be at a standstill or drift slightly (leave its position at a slow 

speed). 

CAUTION! The drive can now leave its position and move to an end position at 

full speed. Take safety measures to prevent personal injury and damage. 

The drive stays in the current position (with ENABLE the actual position is 

accepted as the required position). If the drive moves to an end position, the 

polarity is probably wrong. 

Manual (HAND) operation If START is disabled the axis can be moved manually with HAND+ or HAND-. 

After disabling the HAND signal, the axis stops in a controlled manner at the 

current position. 

Activating START With the start signal the demand value chosen by the digital switching inputs is 

accepted and the axis moves to the predefined target position. 

If START is disabled, the axis stops in the preset deceleration distance D:S. 

Optimize controller Now optimize the controller parameters according to your application and your 

requirements. 


4 Technical description 

4.1 Input and output signals 

Connection Supply 


PIN 3 Power supply (see technical data) 

PIN 4 0 V (GND) connection. 

Connection Analogue signals 

PIN 9/10 Analogue position actual value (X), range 0… 100% corresponds to 0… 10V 

PIN 11/12 Potential for analogue feedback and command signals. 

PIN 15/16 A Version: Differential output (U) ± 100 % corresponds to ± 10 V (0… 10 V at PIN 15 and 

PIN 16). I Version: ± 100 % corresponds to 4… 20 mA (PIN 15 to PIN 12). 

12 mA is the neutral position (0 % output signal). 

< 4 mA indicates that there is an error and the module has not been enabled. It must be 

ensured that the valve switches off at < 4 mA. 

Connection Digital inputs and outputs 

PIN 8 

PIN 7 

Enable input: 

This digital input signal initializes the application and error messages are deleted. The 

controller and the READY signal are activated. The output signal to the control element is 

enabled. 

The actual position is accepted as the command position and the drive remains stationary 

under control at this position. 

START (RUN) input: 

PIN 5 Auto/Hand- input: 

The position controller is active and the external analogue demand position is accepted as 

the demand value. If the input is disabled during the movement, the system is stopped 

within the set emergency stopping distance (D:S). 

Activated = Automatic mode, deactivated = hand mode. 

PIN 6 Sel 1 / HAND+ input: 

a) Selection input 1 

b) Hand mode (START = OFF), The axis drives with the programmed speed (parameter 

HAND:A). After the deactivation the command position is set to the actual 

position. 

PIN 13 Sel 2 / HAND- input: 


PIN 14 Sel 4 input: 

PIN 1 

PIN 2 

b) Hand mode (START = OFF), The axis drives with the programmed speed (parameter 

HAND:B). After the deactivation the command position is set to the actual 

position. 


READY output: 

ON: The module is enabled; there are no discernable errors. 

OFF: Enable (PIN 8) is disabled or an error has been detected. 

STATUS output: 

ON: INPOS message. The axis is within the INPOS window. 

OFF: INPOS message. The axis is outside the INPOS window. 


4.2 LED definitions 


LEDs Description of the LED function 

GREEN Identical to the READY output. 

OFF: no power supply or ENABLE is not activated 

ON: System is ready for operation 

Flashing: Error discovered. 

Only active when SENS = ON. 

YELLOW Identical to the STATUS output. 

OFF: The axis is outside the INPOS window. 

ON: The axis is within the INPOS window. 


4.3 Circuit diagram 

POS-122A 

3,5 mm JISC-6560 Buchse 

12 V 

5 V 

3 

DC 

24 V 

24V 

RS232 C 

9600 Baud 

DC 

4 

0 V 

0V 


power supply 

offset x 

x = -1000.. 1000 

valve adaption 

differential input 

of actuator 

min:i x 

i = A|B 

x = 0..5000 

acceleration A 

ramp A 

15 

Output: A (0..10)V 

a:i x 

i = A 

x = 1..2000 ms 

d:i x 

i = A 

x = 50..10000 

x xw 

10 

9 

0..10V 

Feedback position 

+ 

- 

u 

16 

max:i x 

i = A|B 

x = 5000..10000 

11 

0 V 

0 V 


Output: B (0..10)V 

trigger x 

x = 0..2000 

a:i x 

i = B 

x = 1..2000 ms 

d:i x 

i = B 

x = 50..10000 

12 

command value storage 

pol x 

x = +|- 

acceleration B 

ramp B 

24 V in 

6 

Sel 1 / Hand+ 

I version: 4... 20 mA output 

PIN 15 = +, PIN 12 = GND 

w 

(Pos.) 

(Vel.) 

s:i x 

v:i x 

i = 0..7 

x = 0..10000 

24 V in 

13 

Sel 2 / Hand- 

24 V in 

14 

Sel 4 

general commands 

Ready 

1 

24 V out 

Control program 

InPos 

2 

24 V out 

24 V in 

5 

Auto / Hand 

24 V in 

7 

Start/Run 

PE by mounting rail 

CONFIGURATION 

dsel:x (ON|OFF) 

hand:i x (i = A|B, x = -10000..10000) 

inpos x (x = 0..2000) 

trigger x (x = 0..2000) 

ctrl x (x = LIN|SQRT1|SQRT2) 

DIAGNOSTICS 

din 

x, w 

xw, u 

v 

SUPPORT 

save 

loadback 

help 

para 

24 V in 

8 

Enable

4.4 Typical cabling 

PLC inputs 

PLC outputs 

Analogue position 

feedback (0..10V) 

PLC outputs 

InPos 

Ready 


Enable 

Start / S-Valid 

Sel 1 / Hand+ 

Auto/Hand 

0 V 

0..10V 

Sel 2 / Hand- 

Sel 4 

PE clip 

1 

5 

9 

13 


2 

6 

10 

14 

0V 

3 

7 

11 

15 

4 

8 

12 

16 

PE clip 

0V 

0..10V 

0..10V 

To power amplifier / 

valve. Use differential input. 

shield 

24V 

0V 

power supply 

(-10V..10V)

4.5 Technical data 

Supply voltage 

Current requirement 

External protection 

Digital inputs 

Input resistance 


[VDC] 

[mA] 

[A] 

[V] 

[V] 

[kOhm] 

Digital outputs [V] 

Analogue inputs 

Signal resolution 

Analogue outputs 

Voltage 


Current 


[V] 

[V] 

[%] 

[V] 

[mA] 

[%] 

[mA] 

[%] 

12… 30 (incl. ripple) 


5 Parameters 

5.1 Parameter overview 


Command Default Unit Description 

S:I 0 0,01 % Presetting the command positions selectable by the binary coded digital 

inputs SEL 1, 2 and 4. 

VC:I 5000 0,01 % Presetting the command velocity selectable by the binary coded digital 

inputs SEL 1, 2 and 4. 

DSEL OFF - Mode of command value activation. 

A:A 

A:B 

D:A 

D:B 

100 

100 

2500 

2500 

ms 

ms 

0,01 % 

0,01 % 

Acceleration time for each direction. 

Deceleration stroke for each direction. 

CTRL SQRT1 - Selection of the control function. 

VMODE OFF - Activation of the NC-generator. 

TH 5000 ms Stroke time for 100% velocity and 100% nominal sensor stroke. 

HAND:A 

HAND:B 

MIN:A 

MIN:B 

MAX:A 

MAX:B 

3330 

-3330 

0 

0 

10000 

10000 

0,01 % 

0,01 % 

0,01 % 

0,01 % 

0,01 % 

0,01 % 

Output signal in manual mode. 

Zero point setting /following error compensation. 

Maximum output signal limitation. 

TRIGGER 200 0,01 % Trigger threshold for activating the following error compensation (MIN). 

INPOS 200 0,01 % Range for InPos signal. 

OFFSET 0 0,01 % Offset value (added to the output signal). 

POL + - Changing the polarity of the output signal. 

SENS ON - Activation and deactication of the internal monitoring functions. 

DIN - - Displays status of the digital inputs. 


5.2 Parameter description 


5.2.1 S (Presetting command values) 

Command Parameters Unit Group 

S:I X I= 0… 7 

x= 0… 10000 

0,01% 

With these parameters eight different command values can be preset. 

Via the inputs SEL 1, SEL 2, and SEL 4 at PIN 6, 13 and 14 the value is chosen by binary coding. 

By activating these inputs with logical high signal the following values can be selected: 

Speicherstelle 0 1 2 3 4 5 6 7 

Eingang SEL 1 0 1 0 1 0 1 0 1 

Eingang SEL 2 0 0 1 1 0 0 1 1 

Eingang SEL 4 0 0 0 0 1 1 1 1 

5.2.2 VC (Presetting velocities) 


VC:I X I= 0… 7 

x= 0… 10000 

0,01 % 

These parameters are the corresponding velocities to the chosen command value. Each target position will 

be driven to with it’s own maximum speed. For example: if S:1 is selected via the digital inputs command 

the related speed of VC:1 is also selected by this choice. 



5.2.3 DSEL (Deactivation of the S-VALID) 


DSEL x x= ON|OFF - 

This command changes the way of activation of new command values. 

DSEL = OFF: A new target position is taken over by setting S-VALID (PIN 7) from low to high. 

DSEL = ON: A new target position is taken over directly while START (PIN 7) is on high level. 

5.2.4 A (Acceleration time) 

Ramp function in ms. 


A:I X i= A|B 

x= 1… 2000 

The acceleration time for positioning is set for each direction (drive out:A / drive in:B). 

Normally A = flow P-A, B-T and B = flow P-B, A-T. 

5.2.5 D (Deceleration /braking distance) 


D:I X i= A|B 

x= 50… 10000 


ms 

ms 

0,01 % 

0,01 % 

This parameter is specified in 0,01%. 

The deceleration stroke is set for each direction of movement (A or B, quadrants 2 and 4). The control gain 

is calculated internally depending on the deceleration distance. The shorter the deceleration distance, the 

higher the gain (see CTRL). A longer deceleration distance should be specified in the event of instability.


5.2.6 CTRL (Deceleration function characteristic) 


CTRL X x= lin|sqrt1 

|sqrt2 

- STD 

The deceleration characteristic is set with this parameter. In case of positively overlapped proportional 

valves the SQRT function should be used. The non-linear flow function of these valves is linearized by the 

SQRT 2 function. 

In case of zero lapped valves (control valves and servo valves) the LIN or SQRT1 function should be used 

regardless of the application. The progressive characteristic of the SQRT1 function has better positioning 

accuracy but can also lead to longer positioning times in individual cases. 

LIN: Linear deceleration characteristic (gain is increased by a factor of 1). 

SQRT1: Root function for braking curve calculation. The gain is increased by a factor of 3 (in the target 

position). This is the default setting. 

SQRT2: Root function for braking curve calculation. The gain is increased by a factor of 5 (in the target 

position). This setting should only be used with a significantly progressive flow through the 

valve. 

Velocity 

CTRL = LIN 

Braking stroke 

D:A or D:B 

Stroke 

CTRL = SQRT 

2 The SQRT function generates constant deceleration and thus reaches the target position faster. This is achieved by 

increasing the gain during the deceleration process. 

Velocity 

CTRL = LIN 

1 Braking function with respect to stroke and time 

Deceleration time 

D:A or D:B 

CTRL = SQRT 


Time


5.2.7 VMODE (Switching over the control mode) 


VMODE X x= ON|OFF 

With this parameter the NC mode (almost closed loop controlled velocity) will be activated. In OFF state the 

stroke depended deceleration is active; the velocity preset limits the output signal. 

In ON state the positioning demand value is generated by a profile generator and the axis drives to the target 

position with the defined velocity. The stroke time is defined by the parameter th. 

5.2.8 TH (Stroke time for speed controlled axis ) 


TH X x= 100… 60000 ms 

The stroke time is defined for the stroke of 100 %. It is also defined for 100 % velocity. 

5.2.9 HAND (Manual speed) 


HAND:I X i= A|B 

x= -10000… 10000 

0,01% 

0,01% 

The manual speeds are set with these parameters. The drive moves in a controlled manner in the defined 

direction when the manual signal is active. After the manual signal has been disabled, the drive remains 

under control in the current position. 



5.2.10 MIN (Deadband compensation) 

5.2.11 MAX (Limitation / Gain ) 

5.2.12 TRIGGER (Response threshold for the MIN parameter) 


MIN:I X 

MAX:I X 

TRIGGER X 

i= A|B 

x= 0… 6000 

x= 3000… 10000 

x= 0… 4000 


- 

0,01 % 

0,01 % 

0,01 % 

The output signal to the valve is adjusted by means of these commands. A kinked volume flow 

characteristic is used instead of the typical overlap step for the position controls. The advantage is better 

and more stable positioning behavior. At the same time, kinked volume flow characteristics can also be 

adjusted with this compensation 3 . 

CAUTION: If there should also be adjustment options for deadband compensation on the 

valve or valve amplifier, it must be ensured that the adjustment is performed either at the 

power amplifier or in the module. 

If the MIN value is set too high this has an effect on the minimum speed, which can then 

no longer be adjusted. In extreme cases this leads to oscillation around the controlled 

position. 

MIN:B 

MAX:B 

Ausgang 

geknickte Volumenstromkennlinie 

normale Überdeckungskompensation 

TRIGGER Werte 

Eingang 

3 Various manufacturers have valves with a defined non linear curve: e.g. a kink at 40 or 60 % (corresponding to 10 % 

input signal) of the nominal volume flow. In this case the TRIGGER value should be set to 1000 and the MIN value to 

4000 (6000). 

If zero lapped or slightly underlapped valves are used, the volume flow gain in the zero range (within the underlap) is 

twice as high as in the normal working range. This can lead to vibrations and jittery behaviour. To compensate this, the 

TRIGGER value should be set to approximately 200 and the MIN value to 100. The gain in the zero point is thus halved 

and a higher overall gain can often be set. 

MAX:A 

MIN:A

5.2.13 INPOS (In position window) 



INPOS X x= 0… 2000 0,01 % 

This parameter is entered in 0,01 %. 

The INPOS command defines a monitoring window in which the INPOS message is displayed. The 

monitoring window is placed centrally on the required position value. The actual position value within this 

window is signalled by the INPOS message at the status output (see Pin description). The positioning 

process is not influenced by this message. The control function remains active. 

In NC Mode this message is used to monitor the following error (depending on the parameterization). 

5.2.14 OFFSET (Zero correction) 


OFFSET X 

x= -2000… 2000 0,01 % 

This parameter is entered in 0,01 % units.The offset value is added to the output value. Valve zero offsets 

can be compensated with this parameter. 

5.2.15 POL (Output polarity) 


POL X x= +|- - 

This command enables the output signal polarity to be reversed. 


5.2.16 SENS (Module monitoring) 



SENS x x= ON|OFF - 

This command is used to activate/deactivate the monitoring functions (output current and internal failures) 

of the module. 

OFF: No monitoring function is active. 

ON: All monitoring functions are active. Detected failures can be reset by deactivating the ENABLE 

input. 

Normally the monitoring functions are always active(ON or AUTO mode) because otherwise no 

errors are detectable via the READY output. Deactivating is possible mainly for troubleshooting. 

5.2.17 DIN (Input status) 


DIN - - 

This command displays the status of the digital inputs. So you can monitor the status of the system and the 

selected command value. 

5.2.18 PROCESS DATA (Monitoring) 

Command Parameters Unit 

W 

X 

XW 

V 

U 

Demand value 

Actual value 

Error variable 

Speed demand 

Control signal 

The process data are the variables which can be observed continuously on the monitor or on the 

oscilloscope. 


mm 

mm 

mm 

% 

%

6 Appendix 

6.1 Failure monitoring 


Following possible error sources are monitored continuously: 

Source Fault Characteristic 

P-VERSION 

Solenoid A on PIN 17/19 and 

Solenoid B on PIN 18/20 

EEPROM 

(at switching on) 

6.2 Troubleshooting 

Wrong cabling, broken wire. 

The power stage gets deactivated. 

Data error The output is deactivated. 

The module can be activated by 

saving new parameters (pressing of 

the SAVE Button). 

It is assumed that the device is in an operable state and there is communication between the module and 

the WPC-300. Furthermore, the valve control parameterization has been set with the assistance of the 

valve data sheets. 

FAULT CAUSE / SOLUTION 

ENABLE is active, the 

module does not 

respond, and the 

READY LED is off. 


READY LED is flashing. 

ENABLE is active; the 

READY LED is on, the 

system moves to an 

end position. 

There is presumably no power supply or the ENABLE signal (PIN 8) is not present. 

If there is no power supply there is also no communication via our operating 

program. If a connection has been made to the WPC-300, then a power supply is 

also available. 

If the power supply exists, an attempt should be made to see whether the system 

can be moved by means of the HAND+ and HAND- inputs (measuring the output 

signal to the valve helps). 

The flashing READY LED signals that a fault is been detected by the module. The 

fault could be: 

• A broken cable or incorrect cabling to the solenoids (in the P version only). 

• Internal data error: press the command/SAVE button to delete the data 

error. The system reloads the DEFAULT data. 

The control circuit polarity is incorrect. The polarity can be changed with the POL 

command or by reversing the connections to PIN 15 and PIN 16. 



READY LED is on, the 

STATUS LED is not on, 

the system moves to 

the target position but 

doesn’t reach it 

(positioning error). 


READY LED is on, and 

the system oscillates on 

the target. 


Serious positioning errors can result from incorrect parameterization or incorrect 

system design. 

• Is the cylinder position specified correctly? 

• Are the deceleration strokes correct (to start the system the deceleration 

distances should be set to approx. 20… 25 % of the cylinder position 4 )? 

• Is the valve a zero lapped control valve or a standard proportional valve? 

In the case of a proportional valve, the valve overlap which may be present 

should be compensated for with the MIN parameters. Typical values are to 

be found in the valve data sheet. 

The system is working and also actuating the valve. 

Various potential problems could be: 

• The parameterization is not yet adjusted to the system (gain too high). 

• There is severe interference on the power supply. 

• Very long sensor cables (> 40 m) and sensor signal interference. 

• The MIN setting to compensate the valve overlap is too high. 

As a basic principle, the parameterization of the sensor data and the controller 

settings must be carried out first (before switching on). An incorrect demand is 

equivalent to incorrect system design which then leads to incorrect operation. If the 

system oscillates, the gain should first be reduced (longer deceleration distances for 

D:A and D:B) and in the case of overlapped valves the MIN parameter should also 

be reduced. 

Speed too low The drive may be able to move to position but the speed is too low. 

• Check the control signal to the valve. 

• Via the integrated oscilloscope (U variable). 

• Measure the signal to the valve with an external oscilloscope / 

voltmeter. 

• If the control is within the range of ± 100 % (± 10 V), the fault must be 

sought in the hydraulics. 

• If the control signal is relatively low, the following points should be checked: 

• Is the internal/external speed signal limiting the speed? 

• Which setting has been specified for the deceleration distance in 

relation to the POSITION? 

Speed too high The drive should move to position. The drive moves in and out too fast leading to 

uncontrolled behaviour. Reducing the speed (MAX or VC parameter) has very little or 

no effect. 

• The hydraulic system is over-sized. The entire parameterization of the 

movement cycle cannot be reproduced (overlap and deceleration distance 

settings) 

4 The stability criterion of the hydraulic axes must be taken into account. 



6.3 Description of the command structure 

The command structure: 

[nnnn:i x] or 

[nnnn x] 

Meaning: 

nnnn - used for an arbitrary command name 

nnnn: - used for an arbitrary command name, expandable by an index. 

i oder I - a dummy is for the index. E. g. an index can be „A“ or „B“, depending on the direction. 

x - parameter value, in case of special commands more than one parameter are possible. 

Examples: 

MIN:A 2000 nnnn = “MIN”, i = “A” and x = “2000” 

OFFSET 50 nnnn = „OFFSET“ and x = „50“ 

C:IC 2000 nnnn = “C”, i = “IC” and x = “2000” 



7 ADDITIONAL INFORMATION: Power output stage 

7.1 General function 

The power output stages have been developed for controlling proportional valves without spool position 

feedback. The output stage is controlled by the microcontroller on the basic module by means of pulse 

width modulated signals, and the current is continuously controlled. The cycle time for the controller is 

0,167 ms. 

The output stage can be ideally adjusted to dynamic requirements via internal parameters. 

Valve technology: Directional, throttle, pressure and flow control valves manufactured by REXROTH, 

BOSCH, DENISON, EATON, PARKER, FLUID TEAM, ATOS and others. 

Features 

• Two power output stages for 1A, 1,6A und 2,6A 

• Hardware short-circuit protection with 3 µs response time 

• Adjustable PWM frequency, dither frequency and dither amplitude 

• High current signal resolution 

• Optionally for directional, throttle control or for pressure valves 

• Separate power supply for safety-relevant applications 

• Integrated into the standard controller, no additional cabling necessary 

• Optimum price/performance ratio 


7.2 Device description 

99,0000 mm 

Made in Germany 

Date: Add.: 

ID: 

V: 

W.E.ST. Elektronik 


Homepage: http://www.w-e-st.de 

Typenschild und Anschlussbelegung 

Type plate and terminal pin assignment 


LEDs 

RS232C 

Interface 

9 10 11 12 

25 26 27 28 

13 14 15 16 29 30 31 32 

1 2 3 4 

5 6 7 8 

W.E.ST. 

Ready 

Status 

9 10 11 12 

17 18 19 20 

21 22 23 24 

25 26 27 28 

13 14 15 16 29 30 31 32 

45,0000 mm 

114,0000 mm 

Klemmblöcke (steckbar) 

Terminals (removable) 


7.3 Inputs and outputs 

Connection Signal description 

PIN 22 + 

PIN 24 - 

7.4 Circuit diagram 


Power supply: 10… 30 VDC: For safety-related applications, the output stage 

can be deactivated thanks to the separate power supply inputs. 

PIN 17+19 Solenoid current output A 

PIN 18+20 Solenoid current output B 

Connection Signals modified from the standard (A and I version) 

PIN 15 0… 10 V output with the scaled position demand value 

PIN 16 0… 10 V output with the scaled position feedback value 

10..30V 

0V 

Power supply 

24 V 

0 V 

22 

24 

Internal MCU 

interface 

Power output stage 


ia 

ib 

17 

19 

18 

20 

17 

19 

20 

18 

Solenoid A 

Solenoid B 

for expample: 

HAWE valves

7.5 Typical cabling 

7.6 Technical data 


CAUTION: The solenoid cables should be screened due to electro-magnetic emissions. 

CAUTION: plugs with free-wheeling diodes and LED indicators cannot be used with 

current-controlled power outputs. They interfere with the current control and can destroy 

the output stage. 

Supply voltage 

Current requirement 

Fuse protection 

PE Klemme 

Output currents (PWM 

signal, current-controlled) 

Max. solenoid currents 

[VDC] 

[A] 

[A] 

[A] 

10... 30 

Depending on the solenoid type 

(max. 5 A) 

5 (medium time lag) 

1,0 / 1,6 / 2,6 selectable via 

software 

Housing Snap-on module EN 50022 

Temperature range [°C] -20… 60 

Weight [kg] 0,250 

1 

5 

9 

13 

0V 

2 

6 

10 

14 

3 

7 

11 

15 

Polyamide PA 6.6 

Flammability class V0 (UL94) 

Connections 2 x 4-pole terminal blocks 

4 

8 

12 

16 

17 

21 

25 

29 


18 

22 

26 

30 

19 

23 

27 

31 

20 

24 

28 

32 

PE Klemme 

24V 

0V 

Power supply 

Solenoid A 

Solenoid B

7.7 Parameters 

7.7.1 Parameter overview 


Command Default Unit Description 

CURRENT 0 - Switching over the output current. 

DFREQ 120 Hz Dither frequency 

DAMPL 600 0,01 % Dither amplitude. 

PWM 2600 Hz PWM frequency 

PPWM 

IPWM 

7 

40 

- 

- 

Current control loop PI control dynamics. 

The standard parameterization has been used with a large number of proportional vales from various 

manufacturers. This parameterization has proved to be good as long as no special demands are made of 

the application. 

7.8 Parameter description 

7.8.1 CURRENT (Current range switchover) 


CURRENT X x= 0, 1 und 2 - STD 

The nominal current range is set with this parameter. Dither and also MIN/MAX always refer to the selected 

current range. 

0 = 1,0 A range, 1 = 1,6 A range and 2 = 2,6 A range. 

7.8.2 DFREQ (Dither frequency) 

7.8.3 DAMPL (Dither amplitude) 


DFREQ X x= 60… 400 Hz STD 

DAMPL X x= 0… 3000 0,01 % STD 

The dither can be defined with this command. Different amplitudes or frequencies may be required 

depending on the valve. 

CAUTION: The PPWM and IPWM parameters influence the effect of the dither setting. These 

parameters should not be altered again after the dither has been optimized. 

CAUTION: If the PWM frequency is less than 500 Hz the dither amplitude DAMPL should be set 

to zero. 


7.8.4 PWM (PWM frequency) 



PWM X x= 100… 7700 Hz STD 

This parameter is entered in Hz. The optimum frequency depends on the valve. 

CAUTION: the PPWM and PPWM parameters should be adjusted with low PWM frequencies. 

The PWM frequency can only be set in defined steps. This means that there are deviations 

between the specified and the actual frequency. The next highest frequency step is always used. 

7.8.5 PPWM (Solenoid current controller P element) 

7.8.6 IPWM (Solenoid current controller I element) 


PPWM X 

IPWM X 

x= 0… 30 

x= 4… 100 

The PI current controllers for the solenoids are parameterized with these commands 5 . 


- 

- 

CAUTION: These parameters should not be changed without appropriate measurement 

capabilities and experience. 

If the PWM frequency is > 2500 Hz, the dynamic response of the current controller can be increased. 

Typical values are: PPWM = 7… 15 and IPWM = 20… 40. 

If the PWM frequency is < 250 Hz, the dynamic response of the current controller must be reduced. 

Typical values are: PPWM = 1… 3 and IPWM = 40… 80. 

5 CAUTION! This setting is dependent on the dynamic response of the solenoid (inductance). 

EXP

8 Notes

POS-122-1113

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