10-04-2012 07:17 AM
i have to write some libraries for four types above.
But, i only have a normal windows-computer with a normal serial-connection.
Do i see it correct that can then only make "RS232" with this and that 422 amd 485 are then "special" serial-cards?
So for me it seems that 232/422/485 are three different hardware-types.
And only Modbus is a software-protocol that can be created with labview.
Is this correct?
Thanks for help
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10-04-2012 08:00 AM - edited 10-04-2012 08:01 AM
RS232/422/485 are hardware specific. Many RS422 UART cards out there will also handle RS485. Luckily, most of these cards just show up as a COM port, so the software is the same for all 3.
According to Wikipedia, most Modbus devices use RS485 as the hardware layer. I will admit that I have no exprience with Modbus, so I'm not going to offer any advice on it.
10-04-2012 08:12 AM
You will definitely need either a plug-in card or an external module to get RS-422 and RS-485. Nowadays most computer don't even have serial ports anymore, and those that do are RS-232. RS-232 is single-ended. RS-422 is differential, and was designed to extend the range of RS-422. RS-485 was an extension that allowed for true multi-drop applications (where you can have many devices on a bus, and any one could be transmitting/receiving).
From a software perspective, as crossrulz indicated, it would all appear as COM ports.
10-04-2012 08:28 AM
10-31-2012 10:16 AM
I just downloaded the library zip file and there are folders named 71, 82, 85, 86. I have a labview 2010. Which one works for me?
Those folders are typically for the LabVIEW version. Just use the 86 one since that would be the latest (LabVIEW 8.6).