Analog Input AB NI8 Wont Enabled

DzakwanAfif · Mar 12, 2019

Hello, I just needed some help.

I wanna control my drum level using PLC AB and already migrate the DPT wire signal 1-5 V to analog Input NI8

I already set all the IO Config, range, and with the same config with my flow controller. My flow controller works perfectly, but the level controller wont displays their proportional(default) value.

I already check the input voltage at the Analog Input terminal, and it had 1-5 volt depending on my drum level.
And my input analog LED status on the channel that I declare as level control is not on, but in the flow controller is on.

Any helps? I'm already blocked at my troubleshooting

Thankyou

rdrast · Mar 13, 2019

Do you have the commons hooked up on the (unknown)-NI8 module?

Ken Moore · Mar 13, 2019

Since you are sending a voltage signal to a current sensing card. Try a 250ohm resistor at the card.

Dannyington · Mar 13, 2019

The 1746-NI8 has dipswitches on the card to switch between voltage and current input. Have you checked these are in the correct position for voltage? These will need to be set appropriately for each channel.
OFF = Voltage
ON = Current

DzakwanAfif · Mar 13, 2019

Thankyou for the response..

But nope, Im already sure that I set the AI range and turn down the DIP switch to voltage.

The new progress is, it has something to do with the FIRST PASS BIT. Anyone knows the principal mechanism of this instruction?
Thanks

Dannyington · Mar 14, 2019

The first pass bit will only be true for the first scan. Any subsequent scans it will be false.
So this would typically be after power up or swapping to run mode.

DzakwanAfif · Mar 14, 2019

Thankyou, now my level control is enabled when i put my program at subroutine of my flow controller program in the main routine.

But when i declared the first pass bit and put my level control program at a new file (not at subroutine anymore) l, still my level control program wont work.

Any solution of this?

geniusintraining · Mar 14, 2019

Can you post the program? if yes zip the file

Can you see the raw value number looking at the input (not in your program) and does it change, you should be able to change the level and see the input change in the data

Is this a 1756 or 1746 ?

Dannyington · Mar 14, 2019

When you created a new file for the control, did you remember to create a JSR for the new file number?

DzakwanAfif · Mar 14, 2019

Sure i'll post my program soon when im at my workshop.

The value from my DPT is about 3267 until 16383 depending at my level 0-1000 mm H2O..
The level control program works when i put my program at the subroutine of my flow program.

But when i put my level program independent-ly at a new file, it doesnt work again. Why?
My model is 1746-NI8 (edited)

DzakwanAfif · Mar 14, 2019

Why I need JSR when im made the level program in a new file (at main routine) ?

But yes, im using JSR at my level program at subroutine when my flow program is in the main routine

Dannyington · Mar 14, 2019

You don't need one for the main routine, it was only the new file I was asking about. You say it works when it is included in the same file as the working flow controller, or when it is a subroutine being called by the flow control file, but when you move it to its own file it no longer works.

Does the new file have a JSR which is calling it? All files outside of the main file need to be called by a JSR. If not they won't be scanned.

DzakwanAfif · Mar 14, 2019

Wow, so if i had 2 differents file, i must make JSR instruction too?

I dunno, i mean, i just know that JSR just make me jump to another subroutine.
So JSR is needed to scan another file? Not just a subroutine?

Ken Moore · Mar 14, 2019

You mentioned 1746-NI8, so I assume this is some type of SLC controller. By default only ladder 2 is scanned, it is the "Main" program. All other programs are considered to be subroutines, and must be called from the Main Program. So yes, every "program" other than the main one must have a JSR.

DzakwanAfif · Mar 14, 2019

EUREKA..
Thankyou so much now i understand what the SLC scanning mechanism..
Is it controlLogix had the same mechanism like this?

I had programming with ControlLogix too, and make many file in RSLogix5000, but never found the problem like this one

Analog Input AB NI8 Wont Enabled

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