RS485 NI MAX

[LarsUlrich]

This may be the wrong board for this...

I have a device that communicates via RS485 modbus and I am trying to test out its programming codes in MAX.  It uses an old RJ12 connector, and I have an adaptor for RJ12 to RJ45, allowing me to plug it straight into what would normally be the hardwired internet port.

My question is, where would the device show up in NI MAX?  Is it possible to communicate to a device via what is normally used for the internet?  I am used to GPIB devices and when I plug this one in and open up MAX, it is not obvious which is my device.

Thanks!

[RavensFan]

Duplicate Post

[LV_Pro]

The fact that you can adapt the physical jack to one that can plug into a jack meant for ethernet networking will not mean you can communicate with it. You will need a RS485 serial adapter, either an actual card for the computer or a serial to USB adapter. The hardware "behind the jacks" is more important that what connectors are used in the jacks. The hardware for ethernet is totally different from that for a serial port (RS232/RS485, etc.), which is totally different than that for a USB (despited it being called a "universal serial bus" it is not at all the same as the previous "serial" ports). Just as you need a GPIB card to talk over the GPIB cables, you need an appropriate serial card to talk to RS485 devices.

When you have a properly configured RS485 adapter, either a PC card or a USB - RS485 adapter, it should show up as a serial port in MAX. Then you will have the fun of communicating using the MODBUS protocol, another story entirely. When you have the serial adapter, let us know how you are doing, we can help throught the bumps of MODBUS too.

OK, I see that RavenFan and I are at cross purposes, so please continue in the other thread.