Ivgeny (Customer) asked a question.

Edited September 5, 2022 at 10:00 PM
Help to troubleshoot modbus CLICK PLC with GS10

Hello, 1222233333555555WhatsApp Image 2022-09-05 at 1.13.05 PMWhatsApp Image 2022-09-05 at 1.12.56 PMe1f31d7f-bffe-49cd-ad8b-93e64224c627b42e800c-e51f-4822-afb9-49f0d60ad24eWe using CLICK PLC C0-11DD2E-D with Durapulse GS10. I need to send speed value to the drive, the rest commands are made locally. 

I created a project in my plc to send a register for the speed reference to the drive, based on the examples from the YouTube videos that posted by Automation Direct 

I configured the PORT3 of the PLC accordingly to the recommended settings 

Modbus addres -2 

Baudrate 38400, parity - odd ( also tested "none") 

Advanced configuration stays default 

in the settings of the send instruction command :

Slave ID - 1 (according to drive's address P09.00 = 1 )

Modbus function code : write single register 

address type : Modbus 984 addressing

Starting slave address: 402315 ( according to the GS10 drive parameter P09.10 = 42315 

In the drive, I changed the P00.20 to "1" and P00.30 = "1"

I didnt touch the parameter P09.04 its 13 by default 

just to be able to send frequency set point from the PLC via RS485 PORT3 

Since the drive g=has a RJ45 port for the modbus but the PLC has 3-terminal wire connection, Im using a regular ethernet cable (rj45) with cut end in order to wire it to the PLC terminals, so I used the 568B side of the Ethernet cable,

According to the drive's connection pinout :

Pin3,7 = GND (white/green wire )

Pin4 = SG- (blue wire )

Pin5 = SG+(white/blue wire)

 

On the PLC side I connected the 

"blue wire" to RX3 - 

the "white/blue wire" to TX3 + 

the "white/green wire" to LG

 

when I run the instruction in the PLC Im using C1 bit as a rising edge to run the SEND instruction, Im using other bits to see the "sending", "success", "error"

Im setting the new value in the master address, I selected DS2 for it 

the new value which is the frequency I want to change is 1300 (13.00hz)

according to what I see, the sending bit is momentary on and it changed to success 

the value changed to 1300.

the LED indicators of the RX3,TX3 blinks once but in reality, the driver is not changing the speed, it stays in its last or default value 60.00 

please let me know if you already see something wrong in my description, 

I have also my wiring pictures and my PLC code for your review.

 

Please let me know if there's any ideas to fix it

 

thanks 

  • 7 answers
  • 1.06K views

  • Todd Dice (Customer)

    1. The parity should be odd.
    2. You're misunderstanding Modbus read/writes. They should be conditional on port 3 ready or other means. A condition of normally open SC102 is all you need for the write of a single Modbus instruction (it involves more coding if you have multiple Modbus read/writes).
    3. Make what conditions are required to send value to DS2.

  • Ivgeny (Customer)

    Hi Todd,

     

    Thank you for your quick answer,

    Sorry, I never had any experience with click, I based on the AD video of the Click with GS4 VFD via modbus

    There wasn't any explanation about SC102 and SC2 usage

    I need only to write one register to VFD

    regarding SC102, so as I understand I just need to put SC102 N.O. contact as a condition for the SEND function ? please correct me if im wrong.

    regarding the SC2, its a 1st_SCAN bit. sorry its not completely clear for me how and why I should send value to this bit.

     

    Thank you so much for your support

    Expand Post

    • Todd Dice (Customer)

      My apologies, I wrote the wrong address. I meant DS2 (I corrected the post).

       

      Modbus read/writes (aka in Click, receive/sends) are not handled like coding outputs, timers, counters, etc. They are communication instructions meaning they operate continuously. You use the Port 3 ready address to act as a traffic cop. Going further, if you ever have to code multiple read/writes, you can use a counter to control which read/write is in use. You must do as you cannot have multiple read/writes polling the port simultaneously. I've attached an image of some code illustrating this.

       

      Screenshot 2022-09-06 071555 

      Expand Post

  • Ivgeny (Customer)

    Thank you Todd for your support and detailed explanation.

    sorry for more questions, I just getting into it.

    Is it necessary to read from the drive? I just need to write the speed value to it (only one register - integer). The RUN and STOP commands are made locally on the VFDs Digital keypad

    In your example, seams like you writing into a single bits of the address to activate the RUN command and reset error in the drive

    Is the counter's purpose is to be sure you sending different command in separate cycles of 10ms interval, like in deferent timing so so the write or read instructions are never overlap each other ?

    Expand Post

  • ADC TechnologyGroup_05 (AutomationDirect)

    The Frequency Command for the drive is written to Modbus Holding Register 48194. See reference in manual below:

    https://cdn.automationdirect.com/static/manuals/gs10m/ch5.pdf#page=6

     

    The Communication Frequency (P09.10) and the Command Frequency are not the same. See description of the Communication Frequency in the manual reference below.

    https://cdn.automationdirect.com/static/manuals/gs10m/ch4.pdf#page=199

     

    I hope this helps.

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  • ADC TechnologyGroup_05 (AutomationDirect)

    Also, you stated that P09.04 was left at the default value of 13, which corresponds to the following RTU communication settings:

    • Data Bits: 8
    • Parity: None
    • Stop Bits: 2

     

    Based on the screen capture of the CLICK port 3 settings, you would want to change P09.04 to a value of 12 (8/N/1).

     

    <edit> Removed a comment regarding node address.

    Expand Post

  • Ivgeny (Customer)

    Thank you so much Todd and ADC group,

    it works, I just changed the right address in my logic, I had a mistake by picking P09.10, it has some similarity in description

    so I fixed with correct address  48194 and it works perfect

     

    Thanks again, saved my day !

 

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