NI 9237

Please help us with to setup NI 9237 and NI 9411 with NI cDAQ-9174 to measure the load, torque and angle at the same time. We are using RJ 50 for the connection between load and torque sensors to NI 9237.
For the Load cell, we wired positive and negaitve signals and exicitation pins. it is not reading properly....
Questions:
1. Exitation Voltage for the load call is 10V, do we need an external supply?
2. Do we have to attach the Shunt Calibration pins?
3. attaching the specification sheet for Load cell and torque sensors. Please explain.
Attachments:
sesnors.pdf ‏185 KB

Hi Kwindsor,
1. The NI 9237 can supply up to 10 V of excitation internally, so you shouldn't need an external supply.
2. You shouldn't need to connect the shunt callibration
Synchronize 9401 and 9237 Measurements will give you a good idea how to synchronize these measurements. The example is use a count edges task, but you can change this to an angular encoder task for your application. Can you get any measurements on your 9237 at all? This KnowledgeBase article will tell you how to configure this load cell measurement in Measurement and Automation Explorer to test the readings from your load cell.
Regards,
Jim Schwartz

Similar Messages

NI cDAQ-9172 is not recognizing a NI 9237

I am trying to use a NI 9237 with a NI cDAQ-9172 to measure pressure using a pressure transducer. When I plugged the 9237 into the cDAQ it was not recognized. As I remember with this piece of eqiupment, once a module is plugged in it should be recognized and configured. Any ideas?

Hi Matthew,
I'm wondering, do you have the driver installed? As well, is your chassis recognized in Measurement and Automation Explorer? Does the New Found Hardware issue ever pop up when you connect your device? Thanks!
aNItaB
Applications Engineer
National Instruments
Digital Multimeters

NI 9237 External Excitation - VeriStand 2013 SP1

The recommended excitation voltage for my pressure transducers is + 10 VDC. I prefer to use external excitation as per the NI 9237 manual, total power for the module is limited to 150 mW, which in my case is "Four 350 ohm full bridges at 3.3 V". (I will be using (4) full bridge 350 ohm pressure transducers). I am using Scan Engine for EtherCat and have the NI 9237 in a NI 9144 Chassis connected to a cRIO-9081. For troubleshooting, I have two transducers on a pressure calibrator and another RJ50 connection to a NI 9949 breakout. If I select "External Excitation" and have my 10 V power supply connected to the lower EX+, EX- connector, I get an invalid value for my pressure transducer. This is after scaling the value in calibration. The Raw Value is also incorrect. If I leave it set to "External Excitation" but pull the EX+, EX- connector, the EX+, EX- voltage (pins 6 & 7) will go to 4.735 V and I will get a CORRECT pressure reading. If I select Internal Excitation of 3.3V, I will get a correct pressure reading, but I am a little concerned about resolution as the recommended excitation is + 10 VDC for the pressure transducers. My question is: why am I unable to use the external excitation? I have another application with a PXI and EtherCAT chassis and it works OK. I've also tried placing a NI 9237 module in the cRIO-9081 chassis and get the same invalid value that I describe above.
Solved!
Go to Solution.

Do you have the latest version of the Scan Engine and EtherCAT custom device? On the community page for this custom device, the latest bug fix listed specifically refers to this module. Also there is a specific forum for this custom device that it may be a good idea to post on as well if you have not already posted there about this problem.
Miles G.
National Instruments
Applications Engineer

NI 9237 Not reading correctly

Hello,
I have a NI 9237 with a Compaq DAQ Chasis.
I have hooked up a power supply to the AI+ and AI- inputs.
When I read my signal from the NI 9237 with MAX I get the attached waveform. I don't see this waveform when I hook up my scope to the input signal. The Peak of the waveform seems to be the correct measurement.
Any Advice?
Thanks
Dan

Hello Dan,
From the looks of the waveform you included you are getting a current path somewhere. The 9237 is a bridge based acquisition module. There are internal completion resistors that are used depending on which bridge mode you select. The closest you can get to a DAQ device in differential mode would be to use Full Bridge. This should result in a signal close to the square wave you would like to see (I'm assuming this is the goal). You will have to take into account excitation voltage and some other factors to make the magnitudes correlate with your scope results, but the overall shape should be correct.
I have a few questions as well:
1. When you say power supply, are you referring to a signal generator?
2. What bridge mode do you currently have selected?
3. Was I right to assume you should be seeing a standard pulse (square wave) waveform?
Let me know more about your application; hopefully we can get you the results you expect!
Regards,
Chris Behnke
Sr. RF Engineer
High Frequency Measurements

NI 9237 with varriable resistance

Dear All,
I am interfacing NI 9237 module with a vaiiable resistance to just give a demo how to read analoge sensor ,
I am not able to get the values of my varriabe resistance(POT)
I just want to display the variation in a numeric text box as i change the value of POT
I vave made the following connection
VOUT of POT-----------> AI+
EX+--------------------------->5v
EX- --------------------------> GND
I ave not connecteda any other pin of 9237 can you please send me pin connections how do I connect 9237 signals with POT to just see value on text box
I am using scan Interface and using AI3 channel to see the result
rupesh
Attachments:
block.png ‏53 KB
block2.png ‏49 KB

This is a transmitter. That means: it is only an electronic module to generate a current of 4-20 mA from a resistance temperature sensor PT100. You cannot connect this to a NI9217, it needs a Pt100 temperature sensor, they usually come together.
What is your temperature sensor connected to this? Please provide information about it so I can help more precisely. Read the manual, that should have a Input PT100 as shown in the first page: http://www.status.co.uk/files/manual/37.pdf
Then you have 2 options:
1) If you have already a NI 9217 module, you can connect your PT100 temperature sensor directly without using a transmitter. That means: Remove the transmitter, simply connect red cable (1) to RTD+, white cable (2) to RTD- and the second white cable (3) to COM. Use the sample NI 9217 program provided in the samples folder of NI.
2) If you want to use a PT100 sensor + this transmitter, you need a current input module such as NI 9208. There you will read a current of 4-20 mA and convert this to a temperature reading. Again use the sample NI 9208 program provided in the samples folder of NI.
I hope this will help.

Ni 9237, c series card

Hello
iam using Ni9237 card and iam using an 100kg load cell My objective is to measure a weight btw 0 - 50 kg.
iexcitation voltage is 5 v. Sensitivity of the load cell is 2mv/v. reading i get for 0 kg is 0.000646431** v/v
and for 50 kg is 0.00116299** v/v . will i be able measure a weight in grams (or atleast 10 grams ) .
** Places of digit i have mentioned in bold are fluctuating .
Solved!
Go to Solution.

Please confirm the Load Cell specifications
Excitation Voltage = 5 V
Rated Output = 2mV/V
Rated Capacity = 100 Kg
100 Kg Load => 10mV output => 10mV/5V = 2mV/V Output
In your setup, a 50 Kg load instead of 0.00116299 v/V = 1.16299 mV/V
So a 1 g load should give you around 20 nV/V output. Lets see whether it is feasible in NI 9237
As per NI 9237 specifications, the Scaling coefficient = 2.9802 nV/V per LSB (ADC = 24 bits = 224 Levels)
So 20nV/V output lies within the detectable range of NI 9237. You should be able to measure the weight in grams.

NI 9237 maximum voltage range accuracy

Hello,
I'd like to know how to read the datasheet of the NI 9237 for the accuracy. If I read the web page I can read 0.038mV/V but if I read the datasheet It is more difficult.
I'm working with the load cell MT 1241 (OIML R60 C3) with rated capacity of 150Kg. When I use an external excitation (10V) I'm not abble to have a fixed value. I have 0.000xxxy V where x is fixed and y no.

Hi Fabio,
you could try to calculate the correct maximum voltage range accuracy through this document (see attachment).
Regards.
Sabrina
Attachments:
DOCUMENT.jpg ‏274 KB

Ni 9237 calibration -200077

I'm trying to calibrate NI 9237 + NI 9945 quarter bridge strain gage in ni max.
I get Error -200077 occurred at strain gage calibration.
Possible reasons:
Requested value is not a supported value for his property,
Property AI.Min
Requested value -1.0e-3
Valid values begin wih 18.8988984e-6
Valid values end with 103.843984e-3
Channel name: strain
I tried everything, different strain gages, different 9945's different 9237's, different cables, different computers. everything.
I changed every setting I could find in ni max.
I searched forums and inernet and what is there is not helping.
Any ideas? Please? I'm so desperate.
Solved!
Go to Solution.

I just got the same error message over and over.
What went down: When I set my min limit within the highest and lowest allowable values specified in the error dialog window, and then tried again, I got the same error all over again, but the highest and lowest allowable values shown in the window had changed to completely different numbers. This happened several times. No matter what I set my limits to, the max min allowable values would always change, so it would error out every time regardless of what I entered. Sometimes it would complain about the shunt calibration gain factor, that it couldn't set it to either "+inf" or "-inf". Looking closely at the calibration window, I noticed that NI MAX was reading the same strain value, both with, and without, the shunt resistor connected. When the calibraion subtracted Y2 - Y1, it got zero, and the inverse of zero is infinty. That's when I knew for sure it was something in my wiring and started looking into it more deeply.
Cause: Short in the lead wires running to the strain gage. When the specimen was assembled and bolted onto the fixture, the wires were obscured so that noone could see them, and they were crushed between two metal components.
Solution: Check for shorts or other issues in the strain gage wiring itself. I imagine if the strain gage circuit is open, then we would probably see the same error from NI MAX in that case as well.
Recommendation: I would request NI to add some more helpful information in the error dialog box, to suggest to the user to check wiring, etc.

9237 with full-bridge load cell: load cell_null_off_shuntcal.vi throws error 200077

Hi,
I'm trying to use the example
load_cell_null_off_shuntcal.vi with a full-bridge load cell (Honeywell
Model 31, unamplified). I am using LabView 8.6, cDAQ-9172 and NI9237. The
load cell is connected to pins 2,3,6 and 7.
The inputs for the VI front panel
are: internal excitation10V; mV/V 2.1492 (calibration sheet); max weight 10
lbs; bridge resistance 350 ohms (Honeywell specs); 9237 internal shunt
resistance 100 kohms; shunt location R4 (default setting). I have selected
"Do offset null" and "Do shunt cal".
This is the error I receive:
Error -200077 occurred at DAQmx
Perform Shunt Calibration (Bridge).vi:1 Possible reason(s):
Measurements: Requested value is not
a supported value for this property.
Property:
AI.Bridge.ShuntCal.GainAdjust
You Have Requested: -61.980405e3
Valid Values Begin with: 500.0e-3
Valid Values End with: 1.500000
If the "Do shunt cal"
green button is not selected, there is no error. I understand that the Gain
adjust value should be approx 1, whereas the one I get is much larger. The subVI DAQmx PerformShuntCalibration
(bridge).vi contains a "Call library function node" which I don't
know how to interrogate.
Has anyone else had experience
with this error? Do you have any advice on:
1)
How to "see" the calculations being
perfomed inside the "call library function node"?
2)
What the correct shunt element
location for a full bridge load cell is? (although changing this location does
not eliminate the error, I can't find this info).
3)
Anything I may be doing wrong with
my inputs to cause this error?
Thanks,
Claire.
Solved!
Go to Solution.

Hi Claire,
You have to physically connect the SC terminals to one arm of the bridge (normally R3). The terminal is not provided for connecting external resistors.
See example
C:\Program Files\National Instruments\LabVIEW 8.6\examples\DAQmx\Analog In\Measure Strain.llb\Cont Acq Strain Samples (with Calibration) - NI 9237.vi
"A VI inside a Class is worth hundreds in the bush"
യവന്‍ പുലിയാണു കേട്ടാ!!!

Can NI 9474 or NI 9237 be used to control motor pumps

Hi,
I am using cDAQ-9172 as
the data aquisition system and I am planning to control a motor pump to
run fluids, can modules NI 9474 or NI 9237 be used to control the
pump? I know that NI 9505 which is a full H-bridge brushed DC Servo
Drive Module which can be used to control pumps is not compatible with
the cDAQ system. I am very new to this, please help me with it.
Thanks

Hi,
I think some more information about your motor is needed, specific information about what types of control signals it requires along with what voltage it needs as well as current draw/ device name/model number would be helpful. The NI 9474 can supply 5-30V with a 1A max per channel as can be found in the product manual. Please post back with your motor specs and we will be much better equipped to help.
JaceD
Signal Sources Product Support Engineer
National Instruments

Quarter bridge for 9237

How do I select quarter bridge completion settings for 9237 with 9944?
Message Edited by Frederico Barros on 09-28-2007 09:02 AM

The 9237 is capable of full and half bridge measurements without addition equipment. In order to take quarter bridge measurements with the 9237 you need a quarterbridge completion resistor component (like the ni 9944). This turns your quarterbridge configuration into half bridge, which the 9237 can do. You will need one of these completion components for each of your strain gauges.
[will work for kudos]

9237 + full-bridge load cell: load cell_null_off_shuntcal.vi - error 200077

I'm trying to use
load_cell_null_off_shuntcal.vi with load cell (Honeywell Model 31,
unamplified). I am using LabView 8.6, cDAQ-9172 and NI9237. Inputs:
internal excitation10V; mV/V 2.1492 (calib. sheet); max weight 10 lbs; bridge
resistance 350 ohms (Honeywell specs); 9237 internal shunt resistance 100
kohms; shunt location R4 (default setting). Have selected "Do offset
null" and "Do shunt cal".
Error -200077 occurred at DAQmx
Perform Shunt Calibration
(Bridge).vi:1 Possible reason(s):
Measurements: Requested value is not
a supported value for
this property.
Property:
AI.Bridge.ShuntCal.GainAdjust
You Have Requested: -61.980405e3
Valid Values Begin with: 500.0e-3
Valid Values End with: 1.500000
If "Do shunt cal" green
button not selected, no error. Gain adjust should be approx 1. subVI
DAQmx PerformShuntCalibration (bridge).vi contains "Call library function
node" which is locked (?).
Any ideas?
What is the correct shunt element
location for a full bridge load cell? Changing this location does not eliminate
error.
Solved!
Go to Solution.

Hello CFJ,
The problem is most likely in your external connections of the NI 9237 and the load cell. As referenced in the NI 9237 Operating Instructions and Specifications, page 9, the SC+ and SC- pins should be connected across the resistor specified in the DAQmx Perform Shunt Calibration (Bridge).vi (in the case of a full bridge it would be R3).
Let me know if you are still having issues with your calibration.
Message Edited by Dan_K on 01-22-2009 04:31 PM
Regards,
Dan King

Strain measurement using 9237 and cDAQ 9172

I am trying to measure strain using a 9237 and cDAQ 9172.
The strain gage is connected to 9945 (Red wire to EX+, White to IN+ and Black to QTR terminal also tried connected the white and black to IN+ terminal).
The 9945 is connected to 9237 quarter bridge strain measurement module on a cDAQ 9172. I have two 9237 on the cDAQ 9172.
The device passes the test in MAX.
The problem is I cannot read the strain value.
Can anyone help me please?
Attachments:
Strain measure.vi ‏19 KB

Hi jujare,
In the VI you attached, you don't have the bridge configuration set up. The default is full bridge I, so if you have a quarter or half bridge wired up, that is one reason you could be getting bad data. I'd suggest you take a look at "Cont Acq Strain Samples(With Calibration)-NI 9237.VI" in the Example Finder. It shows the configuration for bridge type and has some handy wiring diagrams. You could also add controls to your vi to set the bridge configuration if you'd prefer.
If your strain gauge only has three wires, it's probably a half or quarter bridge. A full bridge needs at least four wires.
I hope this helps!
Regards,

Cable Position Transducer with NI 9237

Hello,
I have a NI 9237 Half/Full-bridge analog input module. Recently I aquired a cable driven position transducer, which is basically a potentiometer. You can find the circuit diagram from the link below or in the attachment.
http://www.celesco.com/_datasheets/sp2.pdf
I realized the NI 9237 requires a half bridge or full bridge circuit in the transducer but apparently the potentiometer is not a bridge circuit, and when I connect the output and excitation terminals to the module, I'm not able to measure the change of voltage or resistance. Do you know any way I can use NI 9237 to measure the potentiometer?
Thank you!
Solved!
Go to Solution.
Attachments:
sp2.pdf ‏566 KB

larryklee
Unfortunately, if your source is not designed for bridge circuit operation, you are probably not going to be able to use the 9237 to take your measurements. At this point, I would recommend a standard voltage input module. I think you might find this worth reading.
Kyle B | Product Support Engineer | ni.com/support

How to modify the ni 9237 example code for 3 9237 modules

I am wanting to modify the ni 9237 example vi(for only one module) for three 9237 modules.
I have tried several approaches but it does not seem to work well.
Your help is greatly appreciated.

There are my files. Thanks in anticipation. This code is modified for only 2 ni 9237 modules. I bet it would be a logical extention upon making it work for 2 modules.
Enoch
Attachments:
NI 9237 Getting Started (FPGA).vi ‏148 KB
NI 9237 Getting Started (Host).vi ‏459 KB
NI 9237 Getting Started.lvproj ‏46 KB

NI 9237

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