One FP-1000 on 2 computers

[Yves]

Hi
Can I use one FP-1000 network module on 2 computers without CoBox-module?

[Aaron_G]

Yves,

Using two computers to talk to one FP-1000 module can be accomplished in several ways, both through hardware and/or software.

One option is to connect the FP-1000 only to one computer and use the FieldPoint OPC Server. Both computers can then talk to the module through the FieldPoint OPC Server on the first computer.
Likewise, another alternative would be to use a DataSocket or other type of data server on the first computer that the second computer can access over a network.

Another option is to use an RS-232 2 way switch box so that both computers can be physically linked to the FP-1000 module. Using a switch box allows for the computers to be able to control which one is linked to the FP-1000 at any given time, which reduces the likelihood
of both computers trying to transmit at the same time and over-riding each other.

Finally, it may be possible to create a Y-cable. However, off the top of my head, I am not sure whether RS-232 transceivers, which are normally intended for point-to-point communication and not multi-drop, are protected against double driving. If they are protected against double driving, then having the two computers with a Y-spliced cable could work without damage, but you would have the problem of both computers deciding to transmit at the same time, causing garbled messages.

Regards,
Aaron

[Yves]

Thanks for your very detailed answer. It was a great help.
I want to use one FP-1000 and some FP-DO-401 (and maybe other modules). And I'd like to assign 8 channels to one and the other 8 channels for the other computer. Is this possible with Y-cable? Because this is what a I planned to do.

[Aaron_G]

Yves,

The biggest problem with the Y-cable is not one computer or the other owning certain channels, it is both computers transmitting at the same time and causing a garbled message. The FieldPoint Serial modules use the Optomux protocol which does include a checksum which is used to reject corrupted messages, but it is possible (although not likely) with both computers transmitting to corrupt the message in such a way that the checksum remains valid, which can then cause undesired results on your outputs. You really need some way to make sure that both computers do not transmit at the same time, whether through a network communication link or through a second serial port.

Regards,
Aaron

[Yves]

Thanks again

Now everything is ok. Maybe I'll replace the FP-1000 through a FP-1600 which would solve a lot of problem.