Hello, I also have a problem with the modbus software. I try to read an address an 207.12 doesn't turn off. I tried a ladder exactly as in the zip file. i use dm0090:2704 91:4 92:1 (node) 93:119(address) 94:2 i tested the modbus slave with modbus poll and the device responded correct. i also use rs485 I read in one of the previous messages the protocol was for the rs232 port and not for the rs485, is this so, what is the difference? Regards Eddy