NI 9476 Operating Instructions

[angelmcdoggie]

Dear Everyone,

I have quite a number of questions regarding the NI 9476 Operating Instructions.

1.  The title mentioned about 24-V Sourcing Digital Output Module.  However I didn't come across a "24 V" inside this manual.  The external power supply is 6 - 36 VDC.  I just wonder where does the 24 V comes into the picture.

2.  At page 8, Increasing Current Drive topic,  to increase the current to a device, connect DO<0..3> in parallel.  Is this strictly DO pins 0 - 3 only? Or can it be any 4 DO pins?

3.  The module has 4 Vsup pins.  If I use up two or more of these pins at the same time, will the voltage or current add up?

4.  Is one Vsup pin dedicated to a DO byte? Or I can use any Vsup pin to any DO pin I want?

5.  How is the sleep mode enabled in the software?

I guess these are all my queries for now.

Thanks a bunch,

A

[Wayne.C]

1.  The title mentioned about 24-V Sourcing Digital Output Module.  However I didn't come across a "24 V" inside this manual.  The external power supply is 6 - 36 VDC.  I just wonder where does the 24 V comes into the picture. 

24V is a nominal output level that is very common in industrial equipment.

2.  At page 8, Increasing Current Drive topic,  to increase the current to a device, connect DO<0..3> in parallel.  Is this strictly DO pins 0 - 3 only? Or can it be any 4 DO pins?

According to the manual, as long as they are driven together from your vi, any number of pins can be connected in parallel.

3.  The module has 4 Vsup pins.  If I use up two or more of these pins at the same time, will the voltage or current add up?

The Vsup pins are internally connected. You can connect only one external voltage supply to the device.

4.  Is one Vsup pin dedicated to a DO byte? Or I can use any Vsup pin to any DO pin I want?

Since the Vsup pins are internally connected, as long as you connect an external supply to one of the Vsup pins, you can use any DO.

[S_Hong]

Hi angelmcdoggie,

It seems that centerbolt has answered all your questions except for the last one.

Now to answer your question regarding sleep mode, you must first note that sleep mode is not featured on all of our chassis and therefore you must ensure that you have a supported chassis. It appears that all of our cRIO-910x Reconfigurable Embedded Chassis (except for the cRIO-9151 R Series Expansion Chassis), the cRIO-9072/9074 Integrated controller and chassis, and the Single-Board RIO (sbRIO) devices have a sleep-mode line. Detailed information on how to enable this line is shown in the LabVIEW help entitled "Enabling Sleep Mode on a Compact RIO Chassis or a Single-Board RIO Device.

How Can I Achieve Low Power Consumption with CompactRIO?

I hope this helps,

[angelmcdoggie]

Thanks everyone again.

oops, the chassis I'm using is a cDAQ-9172. 

I simulated the module via MAX and my DO3:0 were tied up together.  When data = LOW, how come the voltage != 0 V as seen in the matrix? Throughout the simulation, I have not powered off my external PS, simply increase the voltage.

PINS	DATA = HIGH = EXT PS  (Vo high)	DATA = LOW (Vo Low)
DO3:0	6	4.3
	10	7.25
	15	7.7
	20	7.98
	24	8.17

Regards,

A

[angelmcdoggie]

Dear All,

1.  If I use all 32, one DO channel to each relay, how much current is sourced out to each line?

2.  If i tied more than 4 channels altogether, will there be current overloading?

Regards,

A

[S_Hong]

Hi angelmcdoggie,

The reason why you are not getting 0 V as your logical low is because you have no load connected to your 9476. The load will help give a reference to the output and pull it to 0 V.

NI 9476 Module Reads 8 V When in Off State Using 24 V Power Supply with No Load

And to answer your other questions:

1. You can use all 32 DO channels and each should put out a continuous current of up to 250 mA with a 6-30 VDC and 200 mA max with a 30-36 VDC.

2. You should be able to connect as many channels together to combine current as long as you change their logical states simultaneously.

[angelmcdoggie]

It's working now! Thanks S_Hong.

Previously when I measured the current before that posting, the DO voltage measure slipped my mind because I wasnt monitoring it.

I even had a load connected to DO pin because I have trouble capturing the current with the probe model I was using.  In fact, in a separate

experiment that I measured the voltages for high and low data, however without load.

I rerun the experiment but this time, I am able to use a 4 - CH scope & a higher spec current probe model. 

Oh well. Again, thanks for the tip.

Regards,