Surescan aircon 1

I have a surescan aircon 1 compressor interface that talks modbus rtu, 485. i know that I have communication up to the surescan as i ran a modbus slave simulator and I can read data back to my s7-1200 but I cannot get that surescan to give up any data. I know the baud, 9600 and i have node 1 and 2 but the manual I was given has no other data on comms, no modbus registers, nothing. I have tried running a modbus master simulator but I cannot get it to communicate. I am pretty sure its me doing something wrong as I have 2 of them doing the same thing. Anybody ever dealt with them before? Any trick to getting it to give up its data? And if so anybody know the modbus registers? thanks to everyone! software version SF3M02UN

Try looking up the compressor model rather than the interface if that makes any sense. I see Compair (which I think is the manufacture of SureScan) model L11 manual says baud 19200 and address of 1, so 40001.

How long is the cable? Are you using terminator resistors? Are you using shielded cable?

i can use a modbus slave simulator at the end of the cable opposite the plc and the plc will read data from the simulator so the cable, connectors and all associated hardware is good from that point back. I have tried it with the resistor, without, reversed polarity of wires. no luck.

I know the baud rate is 9600, the surescan tells me that. What I dont know is what data from the surescan goes in what modbus register. example modbus register 40001 = discharge pressure, I have the surescan manual but it gives no data what so ever on communications, modbus registers etc...Its 3 pages long so it gives the most basic of information. I have the manual for the compressor as well and it gives no information what so ever on communications.

hello i have a problem i need some help
the aircon l1 is unlock how to make it lock