Technical documentation

W.E.ST. Elektronik GmbH
Analogue inputs
By use of analogue inputs you have to distinguish between symmetrical and asymmetrical inputs.
All analogue inputs must be screened.
The symmetrical input is carried out as a differential input for voltage signals and can be switched over
per software to bipolar or unipolar signals. Especially by use of high-resolution analogue signals an additional
cable twisted in pairs has to be taken.
The asymmetrical inputs are optimized for the two-pole-conductor techniques (voltages or current signals
as usual in the automobile industry). They can be switched over by software between voltage and
current input. A low-impedance GND connection is required for good signal transmission. In this configuration
the return line is the GND of the power supply. Therefore sensors and the control module should be
combined at a common star point (low impedance) with the GND of the power supply. As common potential
the 0V PIN 11 and optionally PIN 12 are used.
All inputs are protected with suppressor diodes and RC-filter against transient overshoots.
Differential input:
Voltage level: bipolar ±10 V (PIN 9 and PIN 10)
unipolar 0… 10 V (PIN 10 against PIN 9)
input resistance: > 91 kΩ
Asymmetrical inputs:
Voltage level: unipolar 0… 10 V (against PIN 11)
input resistance: 25 kΩ
Current level: unipolar 4… 20 mA (against PIN 11)
input resistance: app. 250 Ω
Analogue outputs
The analogue outputs are carried out as symmetrical differential outputs. Because all power amplifiers
have a differential input (especially valves with integrated electronics), an optimal signal transmission
even over greater distances is possible. All analogue outputs have to be wired with screened cables.
Ideally, twisted pair cables are used. For the signal potential or if both outputs are used as two separate
asymmetrical signals (f. e. for plug amplifiers), PIN 12 as GND potential has to be used. All outputs are
protected with suppressor diodes against transient overshoots.
As differential output:
Voltage level: bipolar ±10 V (PIN 15 and PIN 16)
Output current: max. 10 mA
As asymmetrical outputs:
Voltage level: 2 x unipolar 0… 10 V (PIN 15 or PIN 16 against PIN 12)
Output current: max. 10 mA
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