Read Solo 4848 temp. controller values with ML1100

Can anyone help?

Temperature controller has two-wire RS-485 output. Outputs connected to to "A" & "B" of 1761-NET-AIC module. "A" is jumped to 'Term" on AIC. Shield is connected to SHLD & COM. The controller and the ML1100/AIC are the only devices on the network.

Distance between components is about 20'

CBL-AM-000 connects AIC to ML1100 CH-0.

CH-0 set to Modbus Master. All baud, parity, stop, etc. set the same as the temperature controller.

I think I have the MSG set up the right way. Reading 40 16-bit elements from "03 Read Holding Registers (4xxxxx). MB Data address is 4097 (Modbus addres 44097).

I always get error 37 "Message Timed Out In Local Processor". Tried every combination of baud rates, stop bits, handshaking, etc. (I think), but no luck.

I can post screen shots if anyone's interested in giving this a go.

The first thing I would try is to switch the A and B wires.


Just for the record, the ML1100 has built in RS485. You just need a 1763-NC01 cable to break it out from the round DIN connector and set the Control Line setting to RS485

Wow, that was quick. Looks like I probably wasted half a day for nothing!

I'll order a cable.

I assume I just set the CH-0 setting to "Modbus RTU Master", Buad & Parity to match my controller, Control Line to "No Handshaking" and I'm good to go?

Any special termination (looping) required at the break-out end of the cable?

Couple of things to try. The Ml1100 is Modbus RTU, make sure the temperature controller is also set to modbus RTU ( not Modbus ASCII)

Also different vendors sometimes mix Term "A" and "B". So try switching them.

EDIT: You two type faster then I do.

Already tried swapping wires. I have a chart I used to make sure I got all the possible combinations. Didn't know I didn't need AIC, so that was probably my problem all along. I only saw brief flashes of green from the LED under the RS-485 connector. Solid green on other LED.

Reading 40 16-bit elements from "03 Read Holding Registers (4xxxxx).

Click to expand...

Solo Manual page 7-2
DataRegisters

03: Read Holding Registers (maximum limit is read of eight registers)
06: Write Single Register
16: Write Multiple Registers (maximum limit is eight)

Your 40 register read is bad.​