Hello everibody.
I have a CR1000, a SDM-SIO1 and a presure trasducer (KELLER PR41X) compatible with MODBUS on RS485 interface (Half Duplex RTU mode).
I tryed to connect the presure trasducer at SDM-SIO1, but I can't open the correct port because ModBusMaster function seems to be incompatible with the serial port numeration of SDM-SIO1 (32-47) ...
I connect the SDM-SIO1 pin C1, C2, C3, G and +12V with CR1000 pin C1, C2, C3, G and +12V.
I connect the Trasducer RS485A, RS485B and 0V/gnd with Y,Z and 0V over SDM-SIO1 in according with 3.3.3 figure of the SDM-SIO1 manual.
When i use ModBusMaster I have problem with COMPort parameter: I can't use port 32!
Currently the logger/SDM-SIO1 does not support MODBUS communications I am afraid. We have recently updated our sales literature/manuals to emphasise this point.
You will either need to use an MD485 in transparent mode OR a simple RS485 to serial convertor connector to a logger comm port to read this sensor.
I will raise the issue of MODBUS support for the SDM-SIO1 again with our engineering department but do not expect any change in the near future.
Duplicate - ignore
* Last updated by: aps on 4/20/2012 @ 3:55 AM *
Maybe I can get around this using normal serial function and simulate the MODBUS?
I meen: open the correct serial port with the correct parameter (1 start bit, 8 data bits, 1 stop bit, no parity and 9600 baud) and the correct mode (RTU Mode). I know the coding system too (8 bit binary, hexadecimal 0-9, A-f) ....
Then send the correct request over RS-485 ....
It's a lot off work, but it's possible? Just in case I can't resolve the problem in another way.
IF you can build the MODBUS packets and decode the response there should be no reason why this would not work.
Does anyone know if this issue has been fixed? I cannot seem to get ModbusMaster() to work using a CR1000 (OS v.26) and a SDM-SIO1. I'm getting zero bytes coming out of the Y (A) and Z (B) terminals. The revision history for the CR1000 states that Modbus support has been added for the SDM-SIO1, but the Compatibility tab on the SDM-SIO1 webpage states that Modbus is not supported.
CR1000 (Rev. 26, #43; Rev. 25, #42)
https://www.campbellsci.com/70_103
Modbus is now supported with the SDM-SIO1, however you are advised to use firmware version 6 or later in the SDM-SIO1 and OS26 or later in the logger. (Both available from the downloads section of this website.) Logger OS 27 (to be released soon) is advised if you want to change from the default bit/parity settings.
Please refer to the latest SDM-SIO1 manual for connection details as this can be confusing with different connection labeling for RS485 systems. See http://s.campbellsci.com/documents/eu/manuals/sdm-sio1.pdf
* Last updated by: aps on 10/9/2013 @ 3:34 PM *
Thank you very much. I look forward to testing my non-default parity setting once OS 27 is released.
OS 27 for the CR800/1000/3000 and OS 6 for the SDM-SIO1 are now available in our downloads section. Here's an example program.
Public MBresult, MBvar(2)
BeginProg
'configure sdm-sio1, sdm address 0 (comport 32)
'for rs485 half duplex 8/N/1 (format 48) at 9600 baud rate
SerialOpen (32,9600,48,0,50)
Scan (20,Sec,0,0)
'modbus query over sdm-sio1
ModbusMaster (MBresult,32,9600,1,4,MBvar,1,1,3,100,0)
NextScan
EndProg
Works great now, thanks!