Connecting to Dixell cooling contollers

Dixell refrigeration controllers have the following features of the implementation of the communication interface:

• The modules often do not have an integrated RS-485 driver, and the connection must be made to the TTL serial bus port via an XJ485-CX type converter
• Modbus RTU fixed transmission format - 9600, 8 data bits, no parity, 1 stop bit, recommended response timeout 500ms
• Some controllers, such as the XC650C, contain 2 network Modbus devices - one controlling the compressors and the other controlling the fans. Therefore, an output relay with the same modbus register will correspond to two different physical relays (for compressor and fan)
• Instrument parameters in the user manual have an alphanumeric code, for example dA2, AL2. These codes are also displayed on the instrument display. The network address of the module is set in the Adr parameter. To obtain Modbus addresses of user parameters (all that can be set by the user), you can use this rule - the first parameter in the table (it is given in the standard user manual) has address HR768, and the subsequent ones can be obtained by adding the corresponding offset - HR769 for the second and so on. d. However, this table does not contain registers storing alarm statuses, state of inputs, etc. A full list of parameters for a specific device is available on request.
• They use Modbus #16 function for writing parameters.