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.
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.