Analog input block Simulink Desktop Realtime

Hi

I am using Simulink Desktop Realtime on Windows platform to acquire sensor data from force torque sensors through National Instruments data acquisition card PCIe 6363. As long as I use one force torque sensor, I use only one connector board (i.e. connected to Connector 0 of DAQ with analog input channels AI 0 - 15) and I use Analog input channels [1,2,3,4,5,6] corresponsing to ai0, ai1, ai3, ai4, ai5 respectively and I can obtain the desired response.

But since I have two force torque sensors in my application, I have to use the second connector board for more analog channels, so the moment I use the second connector board (Connector 1 of DAQ with analog input channels AI 16 - 31) and update the analohg input channles in the analog input block of the Simulink Desktop Realtime from [1,2,3,4,5,6] to [1,2,3,4,5,6,16,17,18,19,20,21] I still get the response only from one sensor connected to connector board 0 (AI 0-15). There is no response for the second sensor.

My udnerstanding was when the board is installed, it is known whether both connectors are in use or not. But I am missing something completely and could not find any solution to it from the documentation. I would like to know how can I make my simulink model pick up the analog channels of the DAQ card for both the connector boards? Do I need to specify use Connector 0 and Connector 1 somewhere? If yes, from where can I get this option please? Or do I need to setup something in the configuration of the model ? I would really appreciate any help in this regard. Thank you.

Best Regards

Answer 1

[Jan Houska]

Hi,

this should indeed work, with no additional setup required. But please verify the setting of the A/D connection option - to be able to use 32 channels, this should be set to single-ended.

Good Luck, Jan

[Ehtisham ul Hasan]

Hi Jan,

Thank you for the kind response. This was indeed one of the settings I was missing. But I think there is still something that is giving me the following issue.

After having configured the analog block A/D connection option to single-ended as per your suggestion. Now, the sensor connected to Analog channels 1 to 6 works fine, but when I exert force on the force torque sensor connected to Analog channels 16 to 21 the sensor connected to Analog channels 1 to 6 mimics the response as well. Which is indeed not desired, as the second sensor should also give me explicit response incase of exxternal force.

It came to my mind the common ground might required but I assume the power supply powering up the two connector boards has in itself the common ground already and it should not be an issue. I have tried to seperately check the sensors on Analog channels 1 to 6 (single-ended) and on Analog channels 16 to 21 (single-ended) by exerting force using calibrated weights of 2 kg and 5 kg. Sensor connected to AI 1 to 6 is showing desired response while the second sensor when attached to AI 16 to 21, does not respond correctly. Would really appreciate help to sort the issue. Thanks

Best Regards

[Jan Houska]

Hi Ehtisham,

this very much looks like a problem with incorrect grounding. Please take a look at the NI tutorial to learn how to connect your sensors correctly. This depends on if and how is the output from the sensors connected to ground, so I cannot give any detailed suggestion. You may want to use non-referenced single-ended or differential connection, and in case of differential connection, please be aware of the fact that each signal uses two input pins, so you would have only 16 input channels available.

Good Luck, Jan