5069-SERAL to WeighHead setup help

[Chris90]

Hi all, have a project which requires reading a weigh head weight over ASCII. Never really touched ascii so struggling a bit. The weigh head is in cyclic mode so I’m just reading the received data and looks like I’m getting data but not sure it’s at all sensible. First question really would be how do I set up the start and end delimiters according to the manual?

 

[drbitboy]

The termination/deliver character should be carriage return a.k.a. <CR> a.k.a. ASCII code 13 decimal = 0x0D hexadecimal.

The $(24H) initial character of each sample is the dollar sign character '$'

The input SINT data shown have neither of those characters, so I suspect the is a problem with the serial communication. It could be a mismatch in baud rate, stop bits, parity bit configuration. If this is RS-485, it could be that the signal wires are backwards.

 

[Chris90]

Thanks, just confirmed and it should be 232, confirmed baud rate etc but getting nothing at all so will have to trace it from the weigh head (it goes fibre from the unit to a converter in our panel as shown attached), all provided by weightron

Just to confirm, with the weigh head set to cyclical (as opposed to remote commands), I should just be able to read straight away without transmitting anything / setting up the ascii transmit parameters?

 

[drbitboy]

Just to confirm, with the weigh head set to cyclical (as opposed to remote commands), I should just be able to read straight away without transmitting anything / setting up the ascii transmit parameters?

Yes, it may get messy at startup as the buffer/UART will be full, so the code may need to throw some initial data away, but once the buffer is emptied and data are being read by the PLC as fast as they are coming in, then yes.

 

[Chris90]

Thanks,I’ve swapped the wires and I have activity now and data looks sensible (weigh head is reading 0).I just need to manipulate the data now

 

[drbitboy]

Thanks,I’ve swapped the wires and I have activity now and data looks sensible (weigh head is reading 0).I just need to manipulate the data now

 

[drbitboy]

I just need to manipulate the data now

I noticed in the middle attached image of the original post that you can configure the PLC serial port to detect both "Start" and "Termination" delimiters. I suggest you put '$$' (or '$24' i.e. single dollar sign) as the former and '$r' as the latter and see what shows up in that SINT array Local:1:IO.ASCII.RxData. You might be able to convert directly to a DINT using STOD or to a REAL using STOR instructions.

 

[drbitboy]

Here is an example of how to transfer data from the .RxData array to a string.

https://literature.rockwellautomation.com/idc/groups/literature/documents/um/5069-um003_-en-p.pdf#page=123

• Note the use of the CPS instruction
  • I would use CPS on the Transaction ID so the 5069-SERIAL cannot update data while it is being copied.
• You may need to fiddle the CPS parameters and/or the string length if the Start and Termination delimiters are in the .RxData array.
  • It seems you can exclude them from .RxData using the Exclude option of the delimiter configuration.

 

[Chris90]

that's great thanks very much for your help yes i have logic to act on transaction ID, as well as alarming if transaction ID hasn't updated in x seconds.

 

[L33er]

Dumb question. What model? don't they have ethernet communication?

I have not seen an optical fibre RS-232 system. They gotta be expensive, imo. and the cost of the 5069-SERIAL.

 

[Chris90]

you'd have thought in this day and age they'd have ethernet but they do not . The model is a d440is. Other third party devices we are communicating on modbus TCP/IP.

 

[tdoa]

Dumb question. What model? don't they have ethernet communication?

I have not seen an optical fibre RS-232 system. They gotta be expensive, imo. and the cost of the 5069-SERIAL.

The scale is ATEX rated, so using an optical interface makes sense.
https://www.coopbilanciai.com/en/products/d440is-atex/