Analog over-voltage input protection of PCI-MIO-16E-1

[Hagayw]

As read in this site:

https://www.ni.com/docs/en-US/bundle/370725c/resource/370725c.pdf

There is an over voltage protection to the PCI-MIO-16E-1 that can be switched on/off if I was rightly interpateted this document. The analog voltage input signal I have has overshoot of 20V, and 13V amplitude with pulse width of about 100us. As far as I can understand my signal is in the protection limits as long as the PCI-MIO-16E-1 protection is switched on, but is not protected as long as it switched off. How can I ensure that the device is protected - how can I turn the protection on?

Im using the NI BNC-2090.

A waveform jpg is attached.

[gwd]

I believe you are misinterpreting the table. The table gives the allowable input limits with the BOARD turned on and with the BOARD turned off. So the tolerable input voltages are reduced when the computer is turned off.

[Matt_A]

Hello Hagayw,

The overvoltage protection listed in the NI 6070E/6071E Family Specifications refers to the maximum voltage differential that can be sustained between a channel's input terminal and the common terminal on the module's terminal base without damage occurring to the input circuitry. The post by gwd is correct, the overvoltage is specified with the device powered on and powered off, as such:

"Overvoltage protection
Powered on .................................±25 V
Powered off.................................±15 V"

With this overvoltage level, you could connect the signal you described without damaging the device. However, just because a device can withstand a voltage does not guarantee that it can accurately measure that voltage. The maximum working voltage is the highest voltage that should be applied to a product in normal use, and is the sum of the measured signal and any common mode voltage. The maximum working voltage for the PCI-MIO-16E-1 is specified as follows:

"Maximum working voltage
(signal and common mode) .............Each input should remain
within ±11 V of ground"

So, you will not be able to use this device in the application you described. You mentioned a signal level of +13 V, which is outside the maximum working voltage for this device. I would recommend that you consider the NI-9221 USB-based DAQ device for High-Speed, High-Voltage Signals. This device samples at 800 kS/s, which would be more than fast enough to detect your 100 usec pulse. It also has a maximum voltage range of +/- 60V, which would also work with your signal.