How to connect RS232 pot from 2 HydroRanger 200s to PLC? Any suggestions? Someone said just connect each RS232 cable to Ethernet switch N-TRON 708FX2 and from this Ethernet switch to PLC

 

Recent model HydroRangers can be Modbus slaves (the PLC must be a Modbus RTU master) which talk Modbus RTU over RS-232 (the RJ-11 connector) or over 2 wire half duplex RS-485 (screw terminals).

There are several parameters that require comm setup to enable the Modbus communications, P770-P778 and P782.

The current HydroRanger manual has
- diagrams of the pinouts for the ports.
- parameter settings for Modbus
- 15 pages on the Modbus map and error codes

An ethernet serial server with appropriate Modbus firmware could certainly be used if the PLC runs Modbus TCP over ethernet, however, be aware that a serial server requires configuration for an IP address and configuration of its serial comm side. Nothing is plug and play in the serial comm world. I don't know what an N-tron is.

The PLC's Modbus master functions would have to be programmed to fetch/write, move and format the incoming/outgoing data

Have at it!

 

Hi,

If you need to connect the HydroRanger to something other than a Modbus master, such as a Profibus/DeviceNet master or other Fieldbus master/scanner, HMS has a wide range of gateways that may suit.
The gateway can act as a Modbus master and slave on the other side.
For more information go to:

http://www.anybus.com/support/support-step.asp?ProdType=Anybus Communicator

and select Fieldbus type.

or email me at:
pal [at] hms.se

BR
Patrick Lansdorf

 

I looked at the N-Tron 708FX2, at

http://www.n-tron.com/store/index.php?main_page=product_info&products_id=146

It does not appear to have a serial port. You need a serial port to connect the RS-232 to.

Carl mentioned needing an Ethernet serial server with Modbus firmware. This will require setting the correct baud rate, parity, data bits, stop bits, and possibly making sure the Modbus ID is in a required range. Such a server is shown at http://www.icpdas-usa.com/products.php?PID=460 . That one converts Modbus TCP commands to Modbus RTU commands and passes back the Modbus RTU responses as Modbus TCP responses.

You could also go with just a serial port server like http://www.icpdas-usa.com/products.php?PID=2838 . Your PLC would need to be able to send the entier Modbus RTU command (includes checksum) to TCP port 10001. Again, you need to set baud rate, etc. ahead of time.

Another option is to just see if the PLC has an RS-232 port on it and connect directly.