petchpetals

The connection with Modbus was successful today! Thank you for your help! In case it might help someone, I used PyModbus library for the Modbus communication between my Raspberry Pi and the PLC. To read a 5-register long vector starting at MI3, I use the command client = ModbusTcpClient(host= '#IP address of the slave PLC#' , port=502) rr = client.read_holding_registers(3, 5, unit=2) print(rr.registers) So the address you have to write in the command is simply 3 for MI3. I don't know what unit=2 means but the programs will have an error if this part is left out. Other numbers for example unit=1 seemed to work too. As for the inputs, I noticed another picture on the same data sheet today. I thought that numbers 1-15 on the PLC are numbers of the inputs but I misunderstood. I though my sensors are wired with inputs 9 und 10 but they are actually wired with Inputs I6 and I5, which correspond to AN2 and AN3 respectively.

I used an ethernet cable to connect the PLC with the Raspberry Pi. I will try with the new IP Address setting next time I go to the university. I have set up the HW configuration and paired each analog input with an MI but I wasn't sure about the wiring. I have just found this data sheet about the wiring of V430 model (in attachment). My collegue told me that the level sensor is wired with input 9 and the temperature sensor is wired with input 10. Does that make sense ? because according to the data sheet, it looks like inputs 9 and 10 are only for digital input or temperature sensor and it looks like both input 9 and 10 are supposed to be wired with only one analog sensor, which would be AN0 in the HW configuration (if I understand correctly that #0, #1, #2, #3 on the data sheet correspend to AN0, AN1, AN2, AN3 in the HW configuration?) or am I misunderstanding something? I didn't take a look at the wiring myself. I will have a look again next time I go to the university.

Thank you for your reply I just had the chance to test it at the university today but I had quite a few problems and could not connect the PLC to the RPi via Ethernet yet. 1. Could you tell me how to assign the IP address to the PLC in "TCP/IP - Carn Init" block. How can I know what I should insert for IP Address, Subnet Mask and Default Gateway? 2. When you pair an analog input with a register in "Hardware Configuration", how do you know which Nummer belongs to which input? In my case, my sensors are connected with input 9 and input 10. There are four rows for analog inputs in the "Hardware Configuration". The first two are for temperature sensors (T/C, nV, PT100, Omhs) and the other two are for regular inputs (4-20mA,...)

Hello, I'm very new to PLC programming. This is my first practice. I'm doing a small project for my university. We have a Vision430 controller that is already connected to a temperature sensor and an ultrasonic sensor for level measurement. I have to program the V430 and a Raspberry Pi, so that the RPi can access the sensor values via MODBUS IP. I have watched the tutorial videos and tried to write the ladder logic myself but am not sure if it's correct and I haven't had the chance to go to the university lab to test it with the controller yet because of Covid-19. Could you please check the program I wrote? And about the program for Raspberry Pi. I have to write the register addresses of the V430. I use MI1 and MI2 for the values from both sensors. Does that mean that the register addresses are 40002 and 40003 respectively? Thank you for your advice in advance. ATP16.vlp