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Connect to CR800 via Modbus RTU RS485

Ansgar Jan 22, 2015 05:52 PM

Hi,

I want to connect to my CR800 datalogger via Modbus RTU and RS485 to read out some data automatically. The CR800 shall be configured as Modbus Slave, the other unit (different datalogger with RS485 connection) will be configured as master.
Do I have to use the MD485 in between the two dataloggers to achieve a RS485 connection (CR800->CSI/0->MD485->RS485->Datalogger), or can I also use the SDM-SIO1?

Thanks.

Regards
Ansgar

jtrauntvein Jan 22, 2015 06:07 PM

Under the "Specifications" section for the SDM-SIO1, I found the following:

"The SDM-SIO1 does not support auto baud rate detection nor the use of the serial port for Modbus, DNP, or general PakBus communications."

I believe, therefore, that you will need to use an MD485 configured in transparent mode.

* Last updated by: jtrauntvein on 1/22/2015 @ 11:08 AM *

Ansgar Jan 28, 2015 03:01 PM

Thanks for the answer.

Under the CRBasis instructions of ModbusSlave there is an option of the COMPort for using SDM-SIO1, so I am confused which of the instructions are the right one: SDM-SIO1 or CRBasic?

I like the MD485, but it is too extensive for just using it to extend the CR800 with a RS485 Option.

Regards
Ansgar

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