connecting 3 device together via rs 232

hi everyone
i want to connect 3 instrument together via rs 232
one on is a mighty vacuum pump ,and one is Flow meter
and last one is delta P meter , i use of Citect Ver.6
for monitoring . pls tel me how can i read their data ? i know i can use of 4 - 20 mA analog out put but it is necessry to use of RS-232

Vazgen said:

hi everyone
i want to connect 3 instrument together via rs 232
one on is a mighty vacuum pump ,and one is Flow meter
and last one is delta P meter , i use of Citect Ver.6
for monitoring . pls tel me how can i read their data ? i know i can use of 4 - 20 mA analog out put but it is necessry to use of RS-232

Click to expand...

If you are lucky, the instruments have the Modbus RTU option.
Check this first, and come back for more help if needed.

Kalle

unfortunately not !

Hi there,

I assume that Citec has a Modbus TCP driver..
If so, you may have a solution with the Anybus Communicator gateway. The gateway acts as a Modbus TCP slave on one side and configurable on the serial side. This means that you will need 3 gateways, since your instruments support RS232.
For more information, go to:
http://www.anybus.com/support/support.asp?PID=110&ProductType=Anybus Communicator

or contact
[email protected]

Best regards

Patrick Lansdorf

Hi Patrick ,
thanks for guidance .as you know there are some wire in RS-232
TX - RX - Vcc ... pls tell me have i to use of device net for connecting ?or conect all tx together and all Rx together and ....?
i use of ADAM 4561(USB to RS-232/422/485 Convertet)i mean i have interface with rs-232 out put Now i don't know how can connect 3 moudule (as i said) to interface

I think that RS-232 only support point-to-point connection. You must convert RS-232 into RS-485 and than connect all "A" together, all "B" and all "signal ground"

Hi Vazgen,

I am not 100% sure what you mean... When using RS232, only two nodes can be connected and when doing so RX (on node1) needs to be connected to TX (on node2) and vice versa. And ground (normally pin5 on 9pin Dsub) should be connected to the other device ground.
If you have 3 Usb conectors free on the PC (Citec), theoretically you could connect your devices to 3 Usb-RS232 converters and get the data from the devices to Citec.
I would suspect that your serial devices either use raw ASCII output or some propritory serial protocol, either way you will need to handle that in Citec. If you cannot handle it in Citec, you might need to consider using a gateway as I proposed.

BR

Patrick Lansdorf

Could you please tell us the make and type of the instruments?

K