EN/07.2013/58/82
FREECOOLING (%) 13
HUMIDIFIER (%) 14
FAN DC1 (%) 15
FAN DC2 (%) 16
FAN DC3 (%) 17
FAN AC (%) 18
Force single coil (0x05)
With this function it’s possible to set the state of the machine, for example switching on/off the machine or reset the alarm.
The ModBus address corresponds to the number of the bit.
ModBus function 0x01: read coil status ModBus address
Switching off machine 1
Switching on machine 2
Reset alarms 3
Reset hours of evaporator fan activity or hours of fan activity for custom 13 and 16 4
Reset hours of condenser fan activity or hours of conditioner 1 activity for custom 13 and 16 5
Reset hours of compressor activity or hours of conditioner 2 activity for custom 13 and 16 6
Reset hours of freecooling activity 7
ModBus error messages
If the board receives a fault request, it will send an error message.
Some causes are:
• Noise on serial line
• Request of not present data
• Request at an fault serial address, in this case the board will not answer
• Command code not existent
• Bad checksum, in this case the board will not answer
“Address field ” in the error message
In the error message the address field is the same of the request.
Function code in the error message
The function code is get, setting to 1 the most significative bit of the function code in the request.
For example:
Function code in the request: 0x01 (read coil status)
Function code in the error messages: 0x81
Data in the error message
The data field is composed by 1 byte which shows the error code:
CODE NAME DESCRIPTION
01 ILLEGAL FUNCTION The request function is not present
02 ILLEGAL DATA ADDRESS The address of the request data is not present
03 ILLEGAL DATA VALUE The value into the request is out of range or not possible
04 SLAVE DEVICE FAILURE Typical for gateway: the slave board is not present because the address is fault
Checksum for error message
The checksum is composed by two bytes: the first one is the LSB and the second one is the MSB.
The computation method of the checksum is the CRC16 (Cyclical Redundancy Checking).
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