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PCUS Thermostat - User Manual - 0821EN
13
4. RTU MODBUS
4.1 INTRODUCTION
The PCUS control board is, in the PCUSM version, equipped with a Modbus RTU port which allows an external
supervision system to communicate with the controller.The connection is two-wire and the use of twisted and
shielded 2x0.5 mmq cable is recommended.
The transmission port is able to communicate with the following settings: 38.400 bps, N, 8, 1 (fixed parameters
that cannot be modified).
Below is the list of variables available through the modbus port, the variables are of the holding register type and
therefore function codes 0x03, 0x06 are supported.
CODE
BIT
ACCESS
NAME
MEANING
RANGE
40001
R/W
L0.9
Minimum supply fan speed
1..9 (V)
40002
R/W
L0.a
Maximum supply fan speed
da L0.9..10 (V)
40003
R/W
L0.b
Minimum return air fan speed
1..9 (V)
40004
R/W
L0.c
Maximum return air fan speed
da L0.9..10 (V)
40016
R/W
U0.0
Set temperature
15,0..35,0 (°C)*
40017
R/W
U0.1
Temperature differential
0,0..5,0 (°C)*
40018
R/W
U0.2
Antifreeze set
-10..+5 °C
40019
R/W
U0.3
Antifreeze differential
0..10 °C
40020
R/W
U0.4
Defrost set
-10..5+5 °C
40021
R/W
U0.5
Defrost differential
1..10°C
40022
R/W
U0.6
Hot / Cold proportional band
-10+10 °C
40023
R/W
Fan speed set
0 = low speed, 1 = medium speed,
2 = high speed, 3 = Auto (with
external probe)
40025
R
Dip switch position
Ambient temperature (if present)
(°C)*
40027
R
AI2
External temperature (if present)
(°C)*
40028
R
AI3
Inlet temperature (if present)
(°C)*
40029
R
AI4
Exhaust temperature (if present)
(°C)*
40030
0
R
AI1 alarm
1
R
AI2 alarm
2
R
AI3 alarm
3
R
AI4 alarm
4
R
AI5 alarm
5
R
Alarm P1
6
R
Alarm P2
7
R
Filter
status
Dirty filters alarm
40031
R
P1 temperature
40032
R
P2 temperature
40035
R/W
Set CO2
Ppm
40044
R/W
On / Off from modbus
0=off, 1= on
* Values expressed without comma, for example 20.0 ° C will be read as 200.
