DI(cRIO-9411) automatically generate ture signal in compact RIO.

[numhana]

Hi all,

I have compact RIO system (9101, DI (9411), DO (9472), AI(9215), AO(9263))
My crio system is
DI is monitoring the input signal. When input signal is Ture, DI triggers AI and AO module.

I tested this system, but the input signal which DI recorded are always TURE signal (1)even if I gave F signal(0)to the input signal.
The more weird thing is when I turned the button(highlight execution)on, DI recorded F signal(0) when I gave F signal(0), but if I turned the button off, DI recorded T signal(T).

I guess that Real time system and DI input module generates the wrong signal.

Do you have any idea or any suggestion?
Thank you,

[Ricardo_SR]

Hello,

Under FPGA there are two different VIs to talk to the DIO lines. One group are the Digital Input and Output that will set the lines as you would do with a regular DAQ board, and the second group is the Digital Enable and Digital Data. These is to either make a line input or output. Which VIs are you using?
Another thing that you need to check is how you are grounding the signals.
Thank you


Ricardo
National Instruments

[numhana]

Hi Ricardo,

I am using Digital Input VI.
Actually, I connected the digital output port of DAQ card (6036E) to DI(cRIO-9411) of compact RIO. I used single-ended devices to CRIO-9411 because I used 5V signal of output of DAQ Card(digital output). So I connected the DI port of 6036E to DIa port of CRIO-9411 and digital ground of 6036E to common of CRIO-9411. I did not connect any signal to the DIb port of CRIO-9411, +5 Vout port, and external power supply.

In addition, I attached my files. (testtrigger2 -> FPGA, testtrigger2(RT)-> real-time)
More weird thing is
If I ran the only FPGA program in the FPGA, the DI recorded the signal properly.
But if I ran the real time program and FPGA program, the DI recorded TURE signal even if I gave False signal to port. I think that it seems that DI module (9411) is dead when I ran the real-time programs because crio-9411 does not response any signals properly (always TURE signal).
So I think that there is some problem of communication between Real-time system and FPGA system.

Do you have any idea about it?

Thank you,

Sungjin

[numhana]

Hi Ricardo,

I found out the cause of problem.
When Real time program starts to acquire from Digital Input of FPGA, Digital Input VI start to acquire real value after 1 msec. For 1 msec, signal from Digital Input VI is TURE, or is blinking between FALSE and TURE.

My previous program was that AI acquisition started when DI input was ture. Because DI input was TURE for 1 msec, AI acquisition automatically started whatever DI signal was.
So, I made VI to remove the 1msec TURE signal. Then my system works fine.

Could you tell me why Digital Input is always TURE or is blinking for 1 msec?

Thank you for helping me,

Sungjin

[Ricardo_SR]

I am not sure on the implementation of the implementation of the code. But the high value could be reference to the last value written to that output.
I will try to find a better answer that will describe this behavior.
Thank you

Ricardo