EasyIO
EIO-75 032719
Modbus Registers
The controller supports the following Modbus registers and function codes. The default
communication speed is 9600 bps, 8 data bits, Parity None and 1 Stop Bit. The default Modbus Slave
address is 1. The device Parity can be changed between Odd, None and Even. The baud rate is
selectable between 9600, 19200, 38400, 57600 and 76800 bps. The table shows the register offsets
starting from 0 (0 Base) register address. For example, the Temperature is read from Modbus register
100 using Function Code 04. Some Modbus masters will require one to be added to Modbus registers
(i.e. 1 Base). In this case Function Code 04, register 101 needs to be entered.
Register
Parameter Description
Data Type
Raw Data
Range
FUNCTION CODE 01 - READ COILS
FUNCTION CODE 05 - WRITE SINGLE COIL
FUNCTION CODE 15 - WRITE MULTIPLE COILS
100
Off Mode Override (last transition commands)
0..1
Off - On
101
ECO Mode Override (last transition commands)
0..1
Off - On
102
Show Frost Icon
0..1
Off - On
FUNCTION CODE 02 - READ DISCRETE INPUTS (Add 10,000 for Modicon Addressing)
100
Digital Input Status
0..1
Off - On
101
Relay Output Status
0..1
Off - On
102
Time Clock Status (
not available
)
0..1
Off - On
103
Light Switch Status
0..1
Off - On
104
A/C Switch Status
0..1
Off - On
105
OFF Mode Status
0..1
Off - On
106
Screen Lock Status
0..1
Off - On
107
Party Mode (Boost) Status
0..1
Off - On
108
ECO Mode Status
0..1
Off - On
FUNCTION CODE 04 - READ INPUT REGISTERS (Add 30,000 for Modicon Addressing)
100
Built-In Temperature Measurement
Signed 16
-400...3020
-40.0...150.0°C
(-40.0..302.0°F)
101
Resistive Input 1 Measurement
Signed 16
-400...3020
-40.0...150.0°C
(-40.0..302.0°F)
102
Resistive Input 2 Measurement
Signed 16
-400...3020
-40.0...150.0°C
(-40.0..302.0°F)
103
Current Calculated Setpoint (°C)
Signed 16
-400...3020
-40.0...150.0°C
(-40.0..302.0°F)
104
Interface Current Mode
Unsigned 16
0..3
0 = Comfort
1 = OFF
2 = Party (Boost) Mode
105
Relative Humidity Measurement (with RH
option)
Unsigned 16
0..1000
0..100.0 %rH
106
Alarm State
Unsigned 16
0..256
Bit 0 - Internal NTC (1)
Bit 1 - RI1 (2)
Bit 2 - RI2 (4)
Bit 3 - Humidity Sensor (8)
Bit 4 - DI1 (16)
Bit 5 - DI2 (Not Applicable)
Bit 6 - Time Lost (64)
107
Discrete Input Registers (Bit 0 = DI1, Bit1 =
Relay, Bit 2 = Holiday etc.)
Unsigned 16
0..65,535
N/A
111
Current Fan Speed
Unsigned 16
0..6
0..6
112
Mode Icon Status
Unsigned 16
0..3
0 = Auto
1 = Heating
2 = Cooling
3 = Ventilation Fan
200
Firmware Version
Unsigned 16
N/A
N/A
EasyIO Holdings
www.easyio.com
