SCC 68 to PCI 6229 read in problem

[Dennisvdvoort]

I have connected a SCC 68 module to a PCI 6229 DAQ card. I checken the cable pins and they all work fine, but everytime i try to analyze something, The measurement(voltage, current, etc) slowly builds up until it reaches its max.

It doesnt even matter if the wires are in or not.

This happened during the calibration measurement of a simple 2k resistor and no more then 5 V on it.

I am using an external source, the green light is on without blinking. The AISENSE and AIGROUND are connected. There are no modules on the SCC 68 board. I am using the screw terminals.

Thanks in advance,

Dennis

CNSE research sholar.

[tnek]

Hi Dennis,

When you mention that the measurements are floating to their limits, exactly what type of measurement are you taking (voltage, current, resistance) and how are you configuring the measurement mode (differential, referenced single ended, etc.)? Also, what physical signal do you have connected to the terminals?

I was also wondering if you have your SCC-68 configured in Measurement and Automation Explorer as a screw terminal accessory for the PCI-6229. The directions for how to accomplish this can be found on page 28 of the SCC-68 User Guide and Specifications.

A good test will be connecting the +5V terminal (pin 8 or 14 on the PCI-6229) to one of the analog input channels and a ground pin to the corresponding analog input channel, then taking a differential voltage measurement on the channel. You should read a steady 5V. The pinouts for the PCI-6229 can be found on page 22 of the NI 622x Specifications or in the DAQmx Help under NI-DAQmx Devices Terminals Help.

Regards,
Kent
Applications Engineer

[Dennisvdvoort]

The problem is not in the SCC module, as i've checked the AI1 pin on the cable that enters the PCI card and the voltage is exactly the same as on the multimeter. I am calibrating it, so its a simple resistor with voltage over it.

Ive tried it on everything, but its normally on either voltage or current at differential. On both it floats towards max. Its a screw terminal connected to pin 66(? AI1 in any case, not at the board right now, but according to specifications) and I configured the PCI card in MAX to SCC 68.  

[tnek]

Hi Dennis,

I am not quite sure how you making your readings or how you have your setup connected right now. One thing that may help is using the tasks and connection diagram in Measurement and Automation Explorer (MAX). Assuming that the SCC-68 is configured as a screw terminal accessory for the PCI-6229, right click on the device and create a task for it. You can finish configuring the task. When you are done, you can access the connection diagram with the tabs at the bottom of the task to make sure your signal is connected correctly. This article can provide you with some more information on how to use the connection diagram. I would also make sure that everything is grounded properly. This article provides good information on that. For example, make sure you have bias resistors if your voltage source is floating when measuring in differential mode.

Regards,
Kent
Applications Engineer

[Dennisvdvoort]

Sorry, everyone, I already fixed it. Thanks for the help.