6/29/2022 11:45 PM | |
Joined: 4/23/2022 Last visit: 7/14/2024 Posts: 6 Rating:
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Greeting intelligent community. I know that here i can solve my difficulty. I have a plc s7-1200 cpu 1214c dc dc dc and analog RTD modbus King pigeon m340t module. both devices tested separately work as required. The idea is to read the registers of the RTD module in the PLC, for which i am trying to work with the modbus tcp libraries in Tia portal, still without result i have not been able to read the registers of the module form the PLC. Below are some pictures of what I'm doing. Thank you very much if you can really help me it is a very important project.
Attachment2022-06-29 16-41-44.avi (638 Downloads) |
6/30/2022 7:37 AM | |
Joined: 6/19/2019 Last visit: 7/10/2024 Posts: 697 Rating:
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Hello. I a little bit don't undestand why you use MB_SERVER and MB_CLIENT blocks in same time if your PLC need to be master use MB_CLIENT, if you need to be slave use MB_SERVER. You need use only one block: master or slave This video show how to do modbus master link HERE This video show how to do modbus slave link HERE |
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6/30/2022 2:39 PM | |
Joined: 3/28/2010 Last visit: 8/30/2024 Posts: 1055 Rating:
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The King Pidgeon M340 RTD module is a Modbus TCP server that appears to require a Modbus Slave ID number, normally no longer used by Modbus/TCP, but required for Modbus RTU operation, as stated on page 12 of the manual at the link below: https://images-na.ssl-images-amazon.com/images/I/B1zvJtpC2QS.pdf The m340 module also has a Modbus RTU master capability using the RS-485 port to read external slave devices. Although it implements Modbus write commands, it isn't clear if it can be used as a master to write RTD temp values to an RTU slave. It appears that the RTU master maps the values it reads to the same register set that the Modbus TCP server uses. I would avoid using the Modbus RTU master until communications over Modbus TCP is established and working. The RTU Master register map on page 19 makes no sense: the hexadecimal button is clicked but the map's registers are clearly numbered in decimal base 10. Page 21 shows the register map for the Modbus TCP server registers. Note that the registers are (3)xxxx Input registers read with Modbus Function code 04, not (4)xxxx Holding registers read with Modbus Function Code 03. I suspect that registers (3)0000 through (3)0007 labeled as AINxRTDx are raw values, maybe even A/D counts, whereas (3)0008 through (3)0015 are temperature values in Deg C, with the whatever calibration offset value is added or subtracted. The PLC will have to be a Modbus/TCP client to talk to the RTD server box. |
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6/30/2022 8:54 PM | |
Joined: 4/23/2022 Last visit: 7/14/2024 Posts: 6 Rating:
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"https://www.iot-solution.com/u_file/2012/file/662ef0da4d.pdf" I'm still investigating, i think my ignorance is in the configuration of the ports, at least i don't know which is the port of the modbus slave for the s7-1200. I have configured the RTD module as default modbus port "502" I'm Everything you have written has helped me to scan the modbus communication with a software. Now i can read the registers with "CAS modbus scanner" software. Although i have not yet managed to configure the MB_Client blocks in tia portal to be able to read those registers. AttachmentFiles.zip (546 Downloads) |
Last edited by: Bsarevalo at: 06/30/2022 20:58:31Last edited by: Jen_Moderator at: 07/27/2022 14:01:13PDF and Screenshot added as zip file. |
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