Voltage Measurements with PXI-4070 and SCXI 1127/1331

[Joe]

I'm having trouble getting readings from my PXI-4070 using SCXI-1127/1331 cards. My PXI-4070 is in slot 4 of the PXI-1011 chassis and the SCXI 1127/1331 cards are in slot 1 of the SCXI chassis. I'm using LV 7.1 and DAQ 7.3. The computer/controller is a PXI-8175 with Win2000. I've used the sample programs with no luck. I'm trying to read differential voltages.

[gaving]

Yo Joe,
OK, a few things to be sure that you have configured the system correctly.
1. The DMM is connected correctly to get the signal being routed.
It should be either to the back of the 1127 or directly connected to one of the OUT terminals
2. The SCXI Power is ON
3. The SCXI has been added through MAX.
To do so, right-click on "DAQmx Devices" and add a new SCXI chassis.
It should allow the 4070 to be the controlling card and will make
reference that it is being controlled "through PXI backplane".

[Joe]

I'm getting readings when directly connected to the OUT0 terminals. The SCXI power is on and the 4070 is being controlled through the PXI backplane, however, I can't get readings directly from the backplane.

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@gaving wrote:
Yo Joe,
OK, a few things to be sure that you have configured the system correctly.
1. The DMM is connected correctly to get the signal being routed.
It should be either to the back of the 1127 or directly connected to one of the OUT terminals
2. The SCXI Power is ON
3. The SCXI has been added through MAX.
To do so, right-click on "DAQmx Devices" and add a new SCXI chassis.
It should allow the 4070 to be the controlling card and will make
reference that it is being controlled "through PXI backplane".

---

[gaving]

Hey Joe,
There's a common misconception that the voltages are actually routed through the backplane. They are not. You will need to use a SCXI-1359 and a "HV8 to BAN4" cable to make the DMM connections to the switch module (in particular, the back of the SCXI-1127). These will connect your DMM to the High-Voltage Analog Bus of the 1127. If you do not wish to purchase these items, you will need to make the connections from the DMM (red and black) to the Out0 terminals manually.
Hope this helps