FP-1000and FP-AI-110 power supply

Question

Hello there,
I just set up my first FieldPoint unit and have a question concerning  the recommended Power Supply:
When I read the FP-1000 QuickStartGuide , page 16, I thougt , there is no other way supplying  the  FP-AI-110 module but
by another external power supply .
But It seems , that the FP-AI-110 module is supplied by the internal bus, wihtout cascading power by the terminal. (See attached picture, where only the network module is connected to
an external Power supply )
So which way is recommended by NI ? Input Voltages at the analog module are limitede to max 5V.
Greetings
Beethoven
Attachments:
2008-07-15 002.JPG ‏158 KB

Answer 1

Hi!
   I have in my lab FP-DI-301 and FP-DO-401.  All works, even if I don't cascade V-C terminals, except the output module don't drive their outputs! I mean, V-C are used from output module to actually feed the output current/voltage.  The power/Ready leds lights also with V-C not cascaded because the "logic" part of the modules derive power from backplane.  Also the I/O interfacing circuits work, in fact I can see inputs even without V-C connected.  This holds when the whole system has the same power supply.
   Taking a look at FP-AI-110 manual, "Voltage and current inputs are referenced to the COM terminals, which are internally connected to each other and to the C  terminals. All eight VSUP terminals are internally connected to each other and to the V terminals." and "The [c]FP-AI-110 has eight single-ended input channels. All eight channels share a common ground reference that is isolated from other modules in the FieldPoint system.".  So, I guess, you may refer your inputs to another system, with separated commons.  That's why you are told to connect V-C.
graziano