I&O Manual - ECCS Control System - Categories On Thermal ...

Section 7: Appendix A – Temperature Controller Operation for Modulating
Boilers (Modbus)
7.1. DESCRIPTION
The microprocessor based temperature
controller is utilized for all modulating
Thermal Solutions water boilers. The basic
function of the controller is to modulate the
firing rate of the burner in response to the
boiler heat load. The controller monitors the
boiler water temperature through the use of
a sensor located in the boiler pressure
vessel. The controller compares the boiler
water temperature to the controller’s user
defined operating set-point temperature.
An output signal from the microprocessor
varies the blower speed through the use of a
variable frequency drive (VFD). The gas
valve regulates an appropriate amount of
gas flow for a given air flow or blower
speed. The user may adjust the operating
set-point temperature for a given
application. In addition, the controller has the ability to
change to an alternate set-point through an external signal
for low load conditions (i.e. weekend use, night setback).
Outdoor reset is another standard feature, allowing the
boiler operating temperature to vary based on the outdoor
ambient temperature. The typical result is a higher seasonal
efficiency.
7.2. SET-UP
All of the control parameters have been set at the
factory. There are a few parameters called “Process
Parameters” that must be defined by a qualified
operator. The table below will help serve as a
reference and record when making adjustments.
To alter any of these process parameters follow the
following steps:
• To obtain access into the programming mode
of the controller, briefly press the button
“PGM”.
• You will see “SP1” displayed on the second
line in green LEDs. The previously set
operating temperature will be displayed on the
first line in red LEDs. To increase or decrease
the setpoint 1 value (SP1) use the up and
down arrow keys respectively (st).
• To set the value for “SP2”, briefly press the
“PGM” key and follow the same instructions
above.
• To return to the operating mode press
“EXIT”, otherwise the unit will automatically
return to the operating mode after 30 seconds
of no activity.
To make other adjustments, contact your local
representative or consult the factory.
7.3. MODBUS VERSION USED ON BOILERS CONTROLLED BY THE ECCS SYSTEM
The ECCS control system communicates with the temperature controller using a Modbus communication system. A three wire
shielded cable is connected in a daisy chain configuration to each temperature controller at the CA,CB,CG terminals. This
controller accepts modulating, enable/disable, and local/remote commands from a remote source. Information such as setpoint,
water temperature, frequency feedback, on/off points, etc can also be transmitted back to the control panel.
Parameter
Display
Value
Range
Factory
Setting
User Setting
Setpoint
1
SP1
125-200
180
Setpoint
2
SP2
125-200
0
Digital Setpoint Shift
(optional)
dSP
125-200
0
Outside Temperature
(optional)
Pre-definition of External
Setpoint (optional)
TA
SP.E
C onsult Factory
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C onsult Factory
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Figure 7.1 Process Data
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