RSLogix 500 and modbus communication

Rob735 · Mar 28, 2011

HELP!!!

I am very lost and would very much appriciate some reassurance or a nudge in the right direction.

I have a ML1400 that I am trying to set up to communicate with my control panel. i have the 1762-NC01 adaptor to connect with and am happy with all the hardware I have.

My problem is I have never done Modbus communication setup before and am very lost with how to read the device list from my control panel.

I have spent all morning reading manuals and web-sites and RSLogix instruction help. I am thinking the ASCII controls are what I need to be using but really don't know if this is right?

Does anyone know where I can find a "Modbus for Dummies" explaination. I don't just want anwsers i want to understand what I am doing, I just want valid info that will not confuse me more then I am already.

Thank you in advance
Rob

DamianInRochester · Mar 28, 2011

Rob735 said:
HELP!!!

I am very lost and would very much appriciate some reassurance or a nudge in the right direction.

I have a ML1400 that I am trying to set up to communicate with my control panel. i have the 1762-NC01 adaptor to connect with and am happy with all the hardware I have.

My problem is I have never done Modbus communication setup before and am very lost with how to read the device list from my control panel.

I have spent all morning reading manuals and web-sites and RSLogix instruction help. I am thinking the ASCII controls are what I need to be using but really don't know if this is right?

Does anyone know where I can find a "Modbus for Dummies" explaination. I don't just want anwsers i want to understand what I am doing, I just want valid info that will not confuse me more then I am already.

Thank you in advance
Rob

Hi Rob,
If I may ask, what is the ultimate goal? What device/devices do you hope to communicate with. What will the communication be geared towards(ie. control, data collection, parameter transfer, etc.)?

Modbus.org has everything you need to know to get into the nuts and bolts of it. Like many things though, you need not understand the machinery behind it in order to use it well. Sort of like a good race car driver doesn't necessarily need to know how to re-build an engine.

So are you looking for imformation more so along the lines of a good "user level" understanding, or is that you want to know it to the degree that you could understand what your seeing by looking a the data stream with an oscilliscope.

The first is probably a 1 to 2 hammer job, the latter is more of a 4 to 5 hammer job.

Rob735 · Mar 28, 2011

Damian,

I am trying to connect a ML1400 to a control panel that is controlling refridgeration compressors. The main purpose for this is to collect data, and control a few extra inputs not connected to the panel.

Also the ML1400 will then communicate thru ethernet to a Master PLC as to the status of the control panel and compressor.

widelto · Mar 28, 2011

Rob, send me a pm with your email I got some samples.

Rob735 · Apr 5, 2011

hey guys, I have had little success with this still. Does anyone know when using the 1763-NC01 do you have to run RSLinx to configure driver? If so which driver?

Ken Roach · Apr 5, 2011

When you use Modbus RTU Master and the 1763-NC01 cable, you need to configure the serial port for "485 Network (No Handshaking)", and the Protocol setting will be Modbus RTU Master.

You don't use the ASCII instructions, but rather the ordinary MSG instruction. The MicroLogix controllers have added Modbus RTU as one of the supported protocols.

Post a *.RSS file and you'll get the best commentary on your logic and configuration. ZIP it first so it can be attached to your post.

bernie_carlton · Apr 5, 2011

Half of the battle is to get the information on Modbus addresses and their associated information within the target. Do you have that?

Can you provide a link to a manual on the unit, especially its Modbus information?

Rob735 · Apr 11, 2011

Hey guys, I have figured out that my problem is old software apparently RSlogixs and RSLinx have been updated to give more flexability to the ML1400... hopefully once I can get my computer to cooperate and i can update the software my logic should work... so moral of this issue, make sure you have up to date software URGH..

Why are computers so frustrating sometimes???

RSLogix 500 and modbus communication

Rob735

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DamianInRochester

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Rob735

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widelto

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Rob735

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Ken Roach

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bernie_carlton

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Rob735

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