help with scale and rs485

[jbliss15]

I hope it's a configuration thing I can find

 

[jbliss15]

i have a bunch of the converters, but i'm going to wait and see what the phoenix contact guys say about sending the length in front of the actual data

 

[drbitboy]

i have a bunch of the converters, but i'm going to wait and see what the phoenix contact guys say about sending the length in front of the actual data

Hypothesis: the leading two-byte length is keeping the scale from parsing the query correctly, which is why you don't get a response.

That could be tested from the PC to scale.

 

[jbliss15]

they aren't responding anymore.

 

[jbliss15]

the guy is looking at it now. its adding data in their code messing it up

 

[jbliss15]

ive done some experimenting and i've hooked up my laptop with the virtual com port & rs485 adapter.

my laptop and the PLC are able to send data back and forth.

i see the Q\r\n bytes in the PLC receive buffer, but never seems to make it to the scale.

when i just use the virtual com port to the scale i can send Q\r\n and get a weight back

 

[jbliss15]

Do you have another DLtech DT-9xxx converter? Because the scale is essentially a server, but because it is RS232 it is designed to be a point-to-point device. However, on the RS-485 network side of the DT-9xxx you can have multiple nodes. So if you have an extra DT-9xxx converter, you could put the PC on that network and have it send the Q\r\n string, and then the scale would respond and the PLC would see the scale's response. The only problem would be getting the PLC to ignore the Q\r\n string. Or instead of the Q\r\n you could have the PC send the "start to stream command" and then the PLC would see a continuous stream of data.

This is only an idea for bench testing. The right fix is to get the PLC to not put the two [00 03] bytes on the wire. I suspect the PLC is sending the entire string object, not just the string, and the string object comprises two items: a 16-bit integer length of the string ([00 03]), and the three characters of string data themselves (Q\r\n).

when i talked to the phoenix contact guys they said the extra data is the command for the module to do whatever.

so those bytes shouldn't be sent out.

i think the scale just doesnt like the adapter or something. i dont know what the prob is but it never receives the command or if it does it never sends it back.

when i send Q\r\n from my computer. the PLC sees it, but it must not be making it to the scale???

not sure

 

[jbliss15]

i have a zm405 indicator a load cell and a rs485 option card for the indicator.

i cant' find any manuals for the option card that tells about the serial communmication.

right now its sending back 17 dollar signs characters...

 

[jbliss15]

i can't get it to work

 

[sparky66]

The PLCnext forum is very active, and monitored by Phoenix Contact. All questions get a response quickly. What forum are you referring to?

 

[jbliss15]

i can't get this zm405 with opti0on card to do anything.

if anyone is bored:
https://www.manualslib.com/products/Avery-Weigh-Tronix-Zm405-10249563.html

 

[jbliss15]

<LF>W<CR> Weight of the current scale is return. Standard response (displayed weight)

should i send

10,87,13

or 60,10,62,87,60,13,62

neither works but i dunno what the problem is

 

[jbliss15]

i got it to send "testing" through the card in the admin menu there was a thing to do a test.

but won't send weight