gould

figured it out, thanks 

Hey guys, I'm using a micrologix 1100 to communicate through Modbus to a Ingersoll rand Air Compressor (controller is a xe-145m) and air compressor is a R110i. I have multiple read and writes going to and from the compressor already so I know my communication is good. I'll link the Modbus addresses...heres my set up  Trying to write host/local stop/start load/unload commands to my compressor but I keep getting Modbus error code 3 on my message.  Modbus command: 16 write multiple registers (4xxxxx) (tried single aswell) Size in elements: 1 slave node: 1 Modbuss Adress: 40001  on the modbuss table 40001 should be status/control read/write , it doesn't give me a range but refers to figure 1 and says bit 0 is my local/host command bit 1 is my stop/start... So when I try to use bit 0 and send a '0' into the write message it gives me the error code above.. I also tried a 1, still thing, could anyone take a look at this table for me and figure out what im doing wrong id appreciate it greatly, thanks....  https://www.ccontrols.com/support/dp/XeMModbusRegisters.pdf