max output current module ni9401

[mariomoskis]

hello,how many mA is the maximum current which i can use in the module I/O DIGITAL NI9401?

thanks

[JesusG · Accepted solution]

Hi, mariomoskis,

Each digital line on the 9401 is capable of sourcing 100 uA and sinking 2mA, you can find more information in the specs for the 9401: NI 9401 Operating Instructions and Specifications:

 
http://digital.ni.com/manuals.nsf/websearch/ABFB7FE8BF99B55B862573D0006D5F8B

The 9401 does have over current protection, the following excerpt from the manual explains how it works:

"Overcurrent protection on the NI 9401 allows only a specified amount of current for switching DIO channels or sourcing the output load. If the NI 9401 goes into an overcurrent state, by exceeding the specified maximum switching frequency or the output load, the module power supply begins to drop in

voltage until it completely turns off or the overcurrent condition is removed. When the module is in this state, it can accept new line direction

configuration and output state data but cannot pass valid input data to the software. Refer to the Specifications section for more information about the

maximum switching frequency and output load for each channel."

I hope it helps!

Saludos!

[mariomoskis]

yes

thanks

[Nasrin]

Hi 

I need to generate a 25kHz PWM signal out of 9401. I have a motor driver board (Allegro a4941) which has a PWM input. The PWM gets distorted. Is that due to its low output current? How much load can it support? The attached photos are the direct output of 9401 and the distorted one after applying to unpowered load(a4941 pwm input through couple of resistors). 

[Nasrin]

Hi again

i tested the 9401 pwm out put over a simple resistor, i get a very distorted wave. Another thing is that it seems that there is a min acceptable frequency as well because as I go down to 1 KHz the flat part of the PWM again gets tilted. Any comments I would really appreciate.

[nanocyte]

What size resistor where you using? 100uA is fairly small so you'd want to use a 100kOhm resistor or higher.