Modbus tcp comm btw Micrologix 1400 and staubli robots

s0787671

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Nov 2013
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Dundee
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Hi

Could some one please give some step by step guide on how to setup the modbus msg between Micrologix 1400 client and staubli robot server. Now the staubli part shows me holding registers that I can send data to and receive from.

But I am not sure how to modbus client in Micrologix and set the msg instruction. Where does I enter the IP address of server (robot) on the msg instruction in Micrologix 1400

I have enabled the modbus top in plc, don't know what I should set in Chanel 1 modbus tab.
 
Hi Brenden,

Robot - Server

PLC - Client

I have had alook at the document, but the part isnt clear on how to talk to a server, considering the PLC is going to be the client.

Usually there is a block for talking to server. But here it is only a MSG block and I am noot sure where to input the IP address of the server in the PLC MSG block to talk to the server.
 
s0787671,

In Communications Configuration, on the Channel 1 tab window, you should have Modbus TCP Enable set enabled. You should then see a new tab added at the top Chan. 1 - Modbus. If the ML1400 was acting as a Modbus TCP Server, you would configure clients under that tab. As the ML1400 is a Modbus TCP Client, there is nothing of interest under that tab, unless you want to set a Diagnostics 'N' Data File Number address for storing TCP diagnostic status information for troubleshooting.

Now that Modbus TCP is enabled, when you open a MSG instruction's Setup Screen, you should be able to select Channel: 1 (Internal, Modbus TCP). The Target Device parameters will now have changed to include Ethernet(IP) Address. Here you enter your Robot's Modbus TCP Server IP address. You also need to set a Routing Information(RI) file address for each MSG instruction. You can create an RI Data File the same way you create an N, B, etc., Data File and give it enough elements to cover all your messages. Then, for each MSG instruction, enter a unique RI Data File element number, such as RI10:0, RI10:1, ...RI10:10, etc. Alternatively, if you enter an RI File address that doesn't exist, when you verify the rung RSLogix 500 will auto create the RI Data file for you.

Assuming you have also entered your PLC addresses, Robot's Modbus register addresses, number of elements, etc., you should be ready to go.

G.
 
Micrologix MSG block

Hi friends.. please help me.

I want to send data from micrologix 1400 plc to a HMI terminal via modbus messaging. I configured one micrologix 1400 series B plc with modbus tcp enabled. I communicated plc with HMI. In PLC, I have given modbus data table addresses as follows

Coils(00000x) - B9
Contacts(10000x) - B10
Input registers(30000x) - N11
Holding registers(40000x) - N12

I have used two msg instruction in my plc program.
one to write a bit in plc from HMI.It is working and Iam able to set/reset the bit in plc from HMI.

But in the 2nd MSG instruction, I have given a modbus command to read a plc register (integer value),. I have send data to 400001 register.In HMI I used this register in a display interger field, But this integer value is not updating in my HMI. What may be the possible erors for this....??
 
When you have a new question, please create a New Thread by going to the Live PLC Questions and Answers page and clicking the "New Thread" button.
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In general, you do not have to use MSG instructions with HMI devices; the HMI performs all of the Read and Write requests itself.


Out of curiosity, what did you put in your "Location" field for our Profile ? Write it out here with d-a-s-h-e-s between the letters.

I've seen handful of instances lately where new Forum members had ****** in their Location field, which either meant that they did not wish to disclose it or the PLCTalk censor function is censoring a specific city name in India.
 
dear Ken Roach,
Thanks for your response..
I have to use modbus protocol for communication between my plc and hmi. in HMI, I have only modbus type tags, ie. coils(00000x), contacts(10000x), input registers(30000x) and holding registers(40000x). I want my hmi to read an integer value from N12:0 plc tag to a holding register 400001 in HMI. Thats why I have used MSG read option.. Can u help..?
 
Last edited:
That is what the Modbus mapping configuration in the MicroLogix 1400 is for.

When your HMI requests a Modbus address like "4000x", the MicroLogix 1400 will respond with the contents of "N12:x".

There is no need for an MSG instruction to send the data from the MicroLogix 1400 to the HMI.

95% of the HMI devices I have seen function that way; they are Modbus/TCP peers and perform all of the message initiation.
 
I think there were some guys doing unsolicited advertising on the forum who made the city one of their keywords. I'll see if Phil wants to un-block the word.
 
Thanks for the kind information.
I am using Renu electronics make FP4035tn model hmi.
So u are saying, the hmi tag 40001 will read value from N12:0 automatically without any msg instruction, right..?

OK, I ll try it in the hardware and will get you back....
 

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