1769-SM2 (modbus module)

Hello! I have a one problem with 1769-SM2 module...

I use PLC 1768-L43 and modbus module 1769-SM2. There are 4 devices in modbus net: CH1 - two, and CH2- two (2-wire). In the end of each line I set resistor 100 ohm. I use modbus-simulator on my PC to be sure that data is received from this devices. Data from all deivces I get in simulator.

Then I connect to SM2 - RED diode begins flashing. I use module in Multi-Drive mode, set SW2 in 5X. Module configuration is as it written in manual. (DSI I/O Cfg, RTU Baud Rate, Adresses, etc).

Also I tried to connect devices to SM2 in Single mode (one device to one channel). The result was the same - RED flashing diode.

I suppose when I connect device to module - the GREEN diode flashing (it's written in manual):
"The channel is properly connected to the drive and is communicating, but is not sending I/O to the drive. The channel is set for Modbus RTU Master operation, and is transmitting."

What I do wrong?

I use twisted pair to connect with SM2, RJ45: 4-"D+", 5-"D-".

Module connection parameters in RSLogix 5000:
Single Mode: Input-101/7, Output-100/7, Configuration-102/42.
Multi-Drive mode: Input-101/15, Output-100/15, Configuration-102/42.

Which diode is flashing red ?? on the sm2 or the slave device?? If its on the sm2 is it the port light or module status indicator ??

Also your config looks wrong, see attached...

mxm_88 said:

Hello! I have a one problem with 1769-SM2 module...

.
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Module connection parameters in RSLogix 5000:
Single Mode: Input-101/7, Output-100/7, Configuration-102/42.
Multi-Drive mode: Input-101/15, Output-100/15, Configuration-102/42.

Click to expand...

Wow!~ Only one problem. This module ran me ragged for weeks, getting Modbus to work.
Very little help from you-know-where, and, in the end, I had to fix all of it using a RS485 octopus and analysis software...and a few other tricks.
ProSoft next time, for sure.

Lemming said:

Which diode is flashing red ?? on the sm2 or the slave device?? If its on the sm2 is it the port light or module status indicator ??

Click to expand...

On the SM2, CH1/CH2 status indicator.

Sounds like the message isn't setup correctly.. You are talking to something not an AB vsd I assume ??
I can add a screen shot if the message parameters later on..

I take data from air conditionings. They are worked on PLC Carel.

In Carel there is a Serial Card, RS485, modbus (2-wire).

mxm_88 said:

I use modbus-simulator on my PC to be sure that data is received from this devices. Data from all deivces I get in simulator.

Then I connect to SM2 - RED diode begins flashing.

Click to expand...

Stupid question, but the Carrel AC units are slaves?? Assuming they are, the manual says if the LED blinking ...

In Single mode, the channel is
not receiving communication
from the drive.
In Multi-Drive mode, the
channel is not receiving
communication from one or
more configured drives.

So likely a config issue... Dip sw's need to be "Controller" & "5x". Set the module up as per the image a few posts ago, then drill into the SM2 tags, and setup each channels parameters as required.. Once you have done that, onto the actual messages...

Lemming said:

Stupid question, but the Carrel AC units are slaves??

Click to expand...

Carel has two nets: internal and external. External net is special for modbus data.

Dip sw's need to be "Controller" & "5x". Set the module up as per the image a few posts ago, then drill into the SM2 tags, and setup each channels parameters as required..

Click to expand...

Thanks! But I tried it yet. Nothing...Only my baud rate - 19600(parameter "1"). I tried different modes 1W/5w.

Only what I didn't do - restart Carel.

Check if this document helps...

A while ago I managed to set up a modbus communication with two schenider power monitors using SM2.

If you are still in trouble I can try to dig up a proper code.

Why would you try 1x when the manual says you need 5 x for modbus master ??

Basics... setup the module for MB master, setup the parameters to suit the channel.. The baudrate, parity etc need to be correct to the slaves.. When thats done, it doesn't just work, the ladder needs to be configured to message the required addresses in the slave...

If it were me, id have 1 device on 1 channel, and get it working, then add... But.. set the dip switches, and set the required parameters first. When it's configured correctly, there will be no blinking lights until you set up the messaging...

vxy said:

Check if this document helps...

A while ago I managed to set up a modbus communication with two schenider power monitors using SM2.

If you are still in trouble I can try to dig up a proper code.

Click to expand...

I am still in trouble..

If it were me, id have 1 device on 1 channel, and get it working, then add...

Click to expand...

Oh, I tried this variant but the result was the same.

OK, re-read your original post.. I think you are underestimating what the SM2 is capable of.. (??)

The SM2 is designed for use with powerflex VSD's. If you hang the VSD's off the module, and configure accordingly, all the VSD IO is mapped as per the manual.

If you are using the SM2 with a generic MB slave, the data is pulled in with explicit messaging only...

Post the RS485 parameters of the slave, the SM2 module config, the channel configuration.. Once those are lined up we can move on...

Ok, here are printscreens of all necessary adjustments.