Thermcraft XST-2-0-12-1V1-E28, Инструкция по эксплуатации, Страница: 181 / 260

Installation Installation and Operation Handbook
1.2.4 Snubbers
The relay and triac modules have an internal 15nF/100
Ω
‘snubber’ connected across their output, which is used to
prolong contact life and to suppress interference when switching inductive loads, such as mechanical contactors
and solenoid valves.
The table below shows the module connections and which functions each module can perform. The heating
output is normally connected to module 1, the cooling output to module 2 and the alarm output to module 3,
although the actual function of each module will depend upon how your controller has been configured.
Note: Module 1 is connected to terminals 1A and 1B
Module 2 is connected to terminals 2A and 2B
Module 3 is connected to terminals 3A and 3B.
Module type Terminal identity Possible functions
A B
Relay: 2-pin
(2A, 264 Vac max.)
Heating, Cooling, or Alarm output
Program event output
Valve raise or lower
Logic: non-isolated
(18Vdc at 20mA)
+
−
Heating, Cooling, or Alarm output
PDSIO mode 1,
PDSIO mode 2,
Program event
Triac
(1A, 30 to 264Vac)
Heating, Cooling,
Program event
Valve raise or lower
DC control: non-isolated
(10Vdc, 20mA max.)
Heating, Cooling.
Retransmission of PV, setpoint or control output
Table 1-1: Module 1, 2 and 3 connections
To check which modules are installed in your particular controller, and which functions they are configured to
perform, refer to the ordering code and the wiring information on the controller side labels.
1.2.5 Communications module
The Communications module position will accept any of the modules listed in Table 1-2 below.
The serial communications can be configured for either Modbus, or EI bisynch protocol.
Communications module Terminal identity (COMMS)
Module type
HA HB HC HD HE HF
2-wire EIA-485 serial
communications
− − −
Common A (+) B (
−
)
EIA-232 serial communications
− − −
Common Rx Tx
4-wire EIA-485 serial
communications
−
A
′
(Rx+)
B
′
(Rx
−
)
Common A
(Tx+)
B
(Tx
−
)
PDSIO Setpoint retransmission
− − − −
Signal Common
PDSIO remote setpoint input -- -- -- -- Signal Common
Table 1-2: Communications connections
X
Warning: When the relay contact is open or the triac is off, the snubber circuit passes 0.6mA at
110Vac and 1.2mA at 240Vac. You must ensure that this current, passing through the
snubber, will not hold on low power electrical loads. It is your responsibility as the installer
to ensure that this does not happen. If the snubber circuit is not required, it can be removed
from the relay module (but not the triac) by breaking the PCB track that runs crosswise
adjacent to the edge connectors of the module. Insert the blade of a screwdriver into one of
the two slots that bound it, and twist.
Line Load
+
-
1-6 HA025041 issue 12 Aug 14