[Help required on RS485 Setup]

I have sorted out most with help of you guys, thanks.

I think there is some issue between hex to ASCII conversion whilst sending on protocol. I was trying to send HEX as ASCII but wasn't working then I inserted relevant ASCII characters to which sensor responded. Do I need to convert stored value to ASCII first then link in Scan FB Protocol?

Also, Scan FB is working on when I insert checksum byte as control character as shown below. As a variable it is not working, is it the same issue of ASCII to HEX conversion?

Thanks

 

[Help required on RS485 Setup]

Thanks

By info mode, I assume that it sniffers everything has been received (RX)? Even it doesn't fulfill the scan criteria. Once, the buffer is reset it is gone?

Secondly, I used store block to store value of EA020113 in MI-1 but during online test it showed only lower 2 bytes i.e. 0113 as shown below. Then I used EE12 instead.

Regards

Shahid

[Help required on RS485 Setup]

Dear Joe  T.

Thanks for replying and will follow as per your suggestion.

I connected sensor with PC on RS232 and response was as follow for the same request.

I have only port that is the problem.

I think the checksum byte is also fine in scan function.

Thanks

[Help required on RS485 Setup]

Hello everyone,

I have just completed this program and want some suggestions/ inputs before testing to get this done efficiently.

I'll be really grateful for any suggestions/ errors pointed out.

This is the overall program.

Initialized com port

Protocol Configuration

I need to send this request and stored EA020113 in MI-1.

Stored value (EA020113) is sent after 100ms interval.

This is the send protocol which I have used.

Following is the expected response from the sensor.

I have used STX, 2 byte variable and checksum.

This is my checksum byte setting.

The two byte response is stored in MI-10 and as per response 0-11 bits contain speed. So, I have used following masking technique (0x0FFF AND Response) to get 0-11 bits which are then stored in MI-15.

Then finally created this Numeric variable on HMI (Link: MI-15) to display speed.

 

Please someone go through steps and check everything is fine. Specially, checksum in receive and masking of received message.

Regards

Shahid

[Help required on RS485 Setup]

Thank you very much for replies.

I have gone through some of the examples and I will be using FB Protocol not Modbus.

Once, I'm finished, I will show here to see if there is/ are any mistakes.

Thanks a lot

Shahid

[Help required on RS485 Setup]

Thanks for the reply

I have attached pics of the protocol used by sensor.

For RS485, it supports polling EE (Controller sends 2 byte message and Sensor No. 2 responds with only speed message) and EA (Controller sends 4 byte command and sensor responds in A Format).

I just need a simple example for init com, polling EE, receiving response and display it on HMI for now.

Using this example , I will go for and EF (configuring).

Thanks

[Help required on RS485 Setup]

Hello Everyone,

I am new to this community and to Unitronics PLC. I have worked on the PLCs but I am not familiar with Unitronics PLC and its software.

I am trying to connect with sensor that responds to data over RS485 (polling). I have the sensor registers and commands that are obviously in ASCII.

I need to write and read from sensor over RS485.

Can someone please just provide me a sample program to initialize COM, Send Command, Read Response and display this on HMI?

I just a sample then I can workout for the whole program, the controller I am using is V130-33-T38.

 

Looking for guidance

Shahid