SCXI 1122/1322 RTD connections

[Jim12345 342]

Hello,
I recently purchased an SCXI 1122/1322 to monitor temperature with. Also purchased 8 ready made 3 wire RTDs from National Instruments. I have been unable to find a wiring diagram for more than 1 3 wire RTD - does anyone know the proper method for making these connections to this terminal block?

Thanks,
Jim.

[JustinBritten]

Jim,

The following KnowledgeBase: 2FR6TC55, titled "How Do I Connect an RTD to an SCXI-1121 or SCXI-1122 Module?" documents how to make the connections you desire. You will also find pictures included.

http://pong.ni.com/public.nsf/websearch/6AC6ADE6D5F414A486256B12004CCBC0?OpenDocument

Regards,
Justin Britten

Applications Engineer
National Instruments

[Jim12345 342]

This article adequately explains how to connect one RTD to an SCXI 1122, but what if I want to connect 8 of them? or 16 of them? I can't connect that many wires to the IEX + and - channels, so there must be some other way of making the connections.
Thanks!
-Jim.

[JustinBritten]

The SCXI-1122 provides one voltage excitation channel of 3.33V and one current excitation channel of 1mA. In the case of voltage excitation you must ensure that you do not draw more than 225mA and in the case of current excitation you must ensure that you do not apply a load of more than 5kohms. Figures 4-2 and 4-3 of the SCXI-1122 User Manual (Sep. 1999 edition) show the methods available to connect several loads requiring current excitation. Every piece of equipment that needs excitation is connected to the same excitation channel. There are not individual voltage and current excitation channels for each signal channel.

Regards,
Justin Britten

Applications Engineer
National Instruments