Using Nano as a Protocol converter

[BC SYSTEMS]

Hi,

I'm thinking of using a Nano PLC to read some modbus slave data into the DM via the RS485 port.

Then use My Modbus TCP master access the PLC via the Ethernet port to read / write data back and forth to the slave device.

I need to ensure I don?t end up over writing values that are being read into the same location simultaneously, likewise I'm not sure how the PLC will respond to the TCP port reading a DM value at the same time the serial port is writing the data??

I was also thinking about request / response timing on both ports and if a buffer may be needed??

Do you guys have any words of advice before I commit too much time to this?  do you think I would be better off purchasing an off the shelf serial to Ethernet server?

Any thoughts appreciated.

[support]

Nano-10 is not a protocol converter. You can program it to read the data from the modbus slave and then store the data inside Nano-10's internal memory. But this may not correspond directly with the slave (depending on what memory address they use).

In any case, when you write something to the PLC's memory from another host using Modbus/TCP, the PLC program will need to continuously check that the data has changed and then initiate a WRITEMODBUS command to send the new data to the slave. It is preferable to split out the read and write register space so that the PLC don't overwrite the register just after the master changed the register.

Nano-10 could be used as an excellent data concentrator for Modbus slaves and make them available via the Internet. But if all you want is a protocol converter you should look for a specialty protocol converter to do the job.

[BC SYSTEMS]

Ok Thanks for the advice.