samba pl modbus rtu

[robertmwangi]

hello there, i need some assistance on configuring samba plc sm35-j-R20 for odbus rtu to read an r485 level sensor

[Joe Tauser]

You'll need to add a V100-17-RS4X communication card to the Samba. 

After that, read the the Help on the Protocol function block and look at Help->Examples->Version 900->Project Examples->Communications->Modbus to see how to set Modbus up.  

If you still have trouble have post your program and a link to the datasheet on the sensor so we can have a look.

Joe T.

[robertmwangi]

On 10/22/2021 at 7:38 AM, Joe Tauser said:

You'll need to add a V100-17-RS4X communication card to the Samba. 

After that, read the the Help on the Protocol function block and look at Help->Examples->Version 900->Project Examples->Communications->Modbus to see how to set Modbus up.  

If you still have trouble have post your program and a link to the datasheet on the sensor so we can have a look.

Joe T.

LLS Protocol intergration RS232_RS485_V1.0.pdf  Thanks Joe for the kind help. i still need help. attached is the sensor datasheet. Am using Samba  sm35-j-R20.

[Joe Tauser]

I was incorrect in my previous post mentioning Modbus.  This sensor has it's own protocol.  Take a look at the examples under "Communications ->FB Protocol".

This is not an entry level PLC program. 

Do you have the sensor in hand?  I suggest you first familiarize yourself with serial communications by purchasing a USB to RS485 converter for you computer and learning how to communicate with the sensor using a terminal program on your PC such as Bray's terminal - https://sites.google.com/site/terminalbpp/.  You'll need to know exactly what strings to generate using the Protocol function and it's much easier to learn how the sensor works using a known working send/receive tool such as a terminal.

Joe T.