RS485 keller sensors communication

[MarcoTabarrini]

Hello everybody,

I am using the serial port of a cRIO-FRC II with LV2015 to acquire 2 Keller RS485 pressure sensors. 

To do this I am using the keller library on Real Time, I have no problem when only one sensor is connected but when both are connected the acquisition doesn't work. I see only one sensor and not for all the time. 

I can't see the other sensor in none of the address available, there is someone who knows how to solve this issue?

Thanks in advance,

Marco

[Omar-Abdelhameed]

Hi Marco, 

Can you share picture of the code you have done, I am working on something similar. Thanks. 

[Omar-Abdelhameed]

How did you connected your wires (RS485A & RS485B) to your cRIO port. 

[MarcoTabarrini · Accepted solution]

Hi Omar,

I finally solved the problem. 

I bought a RS485 to RS232 converter (something similar to the one in the pic) and linked the two sensors in parallel. The problem I had is that I had to assign a specific ID address for each sensor before acquiring them.

For doing that I used the k114 adapter of the keller sensors with their proprietary software.

The code in the picture works.

[bduncan@corex.co.uk]

Thanks Marco, 

How did you assign a specific ID address for each sensor before acquiring them, and how did you connected your wires( RS485A & RS485B) into that converter!! Is that converter is usb-RS485 converter or RS232-RS485 converter. 

[Omar-Abdelhameed]

Thank you Marco and sorry for distributing, 

How did you assign a specific ID address for each sensor before acquiring them, and how did you connected your wires( RS485A & RS485B) into that converter!! Is that converter is usb-RS485 converter or RS232-RS485 converter.

[MarcoTabarrini]

It's a rs485-rs232 converter. The connection of the two sensors is as in this scheme.

For the id I have used the sensor producer's software, it is called CCS30 

[Omar-Abdelhameed]

Thank you Marco for your understanding. My worries are that after I connect my transducers to that converter ( RS485 - RS232 converter ) the RS232 will be connected to NI PCI-e 8431/8 board which is using RS485 communication protocol, So do you think that would work or not. This board (68 pin) is connected to NI cable that provides 8 DSUB9 interface ports and shown on the PC as (COM ports). Thank you.