11-23-2020 08:39 AM
Hi,
I am trying using a cDAQ-9132 with a NI-9205 voltage input module and a NI-9263 voltage output module in order to measure a Campbell Scientific 109SS ground temperature probe and a Campbell Scientific CNR4 net radiometer. The ground temperature probe requires a 2.5V excitation from the NI-9263 and a single ended configuration. The CNR4 net radiometer is used in a differential configuration connected to the NI 9205. The CNR4 net radiometer also has a built in thermistor that is needed to accurately measure pyrgeometer irradiance. This thermistor also requires a excitation voltage from the NI-9263 and a single ended configuration.
Right now we only have one wire (the 109SS purple thermistor wire) connected to the COM terminal on the 9205 and both the COM terminals on the 9263 are not connected to anything.
We are experiencing noisy data and getting data/results that do not make sense. I believe this is a wiring/configuration issue more than a LabVIEW issue. See the table below on how this should be wired according to the 109SS and net radiometer manuals.
Some confusion I am having is that the shield wires for the 109SS, net radiometer and net radiometer thermistor all need to go to analog ground. The 109SS and net radiometer thermistor also each have a thermistor reference wire that needs to go to analog ground as well. So my question is then do all the shield wires (3) and thermistor reference wires (2) need to go to the one COM terminal on the 9205? The CNR4 net radiometer also says in its manual that jumpers should be used to connect wires (6, 8, 10 and 12) to analog ground as well. This would give you then 9 wires that need to go to analog ground. The 9263 will also have two COM terminals that need to be referenced to ground as well correct?
Any suggestions on how to go about wiring this setup in order to get accurate readings by referencing a common analog ground between the three separate sensors and the COM terminals on the 9205 and 9263 (if this is even possible to be done with the existing equipment)?
Wire # |
Sensor |
Wire |
Purpose |
Connection To |
1 |
109SS Temperature Probe |
Black |
Voltage Excitation Input |
NI-9263 AO-0 |
2 |
109SS Temperature Probe |
Red |
Analog Voltage Output |
NI-9205 AI-0 |
3 |
109SS Temperature Probe |
Purple |
Thermistor Reference |
Analog Ground |
4 |
109SS Temperature Probe |
Clear |
Shield |
Analog Ground |
5 |
CNR4 Net Radiometer |
Red |
Pyranometer Upper (+) |
NI-9205 AI-1 |
6 |
CNR4 Net Radiometer |
Blue |
Pyranometer Upper (-) |
NI-9205 AI-9 |
7 |
CNR4 Net Radiometer |
White |
Pyranometer Lower (+) |
NI-9205 AI-2 |
8 |
CNR4 Net Radiometer |
Black |
Pyranometer Lower (-) |
NI-9205 AI-10 |
9 |
CNR4 Net Radiometer |
Grey |
Pyrgeometer Upper (+) |
NI-9205 AI-3 |
10 |
CNR4 Net Radiometer |
Yellow |
Pyrgeometer Upper (-) |
NI-9205 AI-11 |
11 |
CNR4 Net Radiometer |
Brown |
Pyrgeometer Lower (+) |
NI-9205 AI-4 |
12 |
CNR4 Net Radiometer |
Green |
Pyrgeometer Lower (-) |
NI-9205 AI-12 |
13 |
CNR4 Net Radiometer |
Clear |
Shield |
Analog Ground |
14 |
CNR4 Thermistor |
Red |
Voltage Excitation Input |
NI-9263 AO-1 |
15 |
CNR4 Thermistor |
White |
Analog Voltage Output |
NI-9205 AI-5 |
16 |
CNR4 Thermistor |
Black |
Thermistor Reference |
Analog Ground |
17 |
CNR4 Thermistor |
Clear |
Shield |
Analog Ground |
11-25-2020 07:11 AM
Any suggestions on this?