05-25-2021 04:56 PM
I am using NI-USB 6289. I notice something weird on the +5 V terminal. When the +5 V terminal is not connected to an external load, the voltage between the +5 V terminal and a ground terminal is +5 V. Nonetheless, when a load (e.g., a 100 kOhm resistor) is connected between the +5 V terminal and the ground, the voltage across the +5 and ground drops to ~3.4 V.
I am not sure what is going on. The DAQ is powered by a cable and also connected to a PC. So, I assume that the current drawn from either a power cord or USB should be sufficient. Can someone please help me with this problem?
05-25-2021 06:28 PM
As per the device specifications, 100k load is totally fine, it would be worth checking the fuse.
Is this issue consistent across all 4 pins (2 on each connector)?
I believe the USB version is externally powered, could you check if the power supply is good?
05-26-2021 02:42 PM
Thank you Santhosh. Unfortunately, I have the NI USB-6289 with the screw terminal pinout. Therefore, only one +5 V terminal is available.
05-26-2021 03:37 PM
As per this image, screw terminal 98 is connected to the fused +5V, were you able to check the Fuses and replace?