LabVIEW

cancel
Showing results for 
Search instead for 
Did you mean: 

Convert NI-9477 To 24V Sourcing Output

I have an NI-9477 32-Channel (Sinking Output) module that I need to "convert," to a Sourcing Output. I understand I can do this through the knowledge article below:

 

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000YI7ICAW&l=en-US

 

I understand that I need to add "a 'Pull-Up' resistor between the output of the I/O to a voltage source."

Output With Pull UpOutput With Pull Up

 

However, I don't know what that means physically. Are there any photos or more specific diagrams showing how to do this on a C Series module? 

 

Specifically, I want to convert all 32 inputs of the NI-9477 module:

 

  1. What do I need to connect and to which pins?
  2. Where do my digital inputs go in this new circuit?

9477 Pinout9477 Pinout

0 Kudos
Message 1 of 11
(4,027 Views)

Do you have a friend or colleague with any experience in Electrical Engineering?  Failing that, have you tried doing a Web search for "pull-up resistor"?  Either method should provide you with a better answer than we could give because you will know all the details of your task and can either (a) explain/show them to your colleague or (b) apply them while reading detailed descriptions and circuits found on the Web about this topic.

 

Bob Schor

0 Kudos
Message 2 of 11
(3,978 Views)

I think I would just invest in a NI-9476, which is a sourcing Digital Output (has Vsup input as the voltage source for all of the outputs).



There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines
"Not that we are sufficient in ourselves to claim anything as coming from us, but our sufficiency is from God" - 2 Corinthians 3:5
Message 3 of 11
(3,969 Views)

Hey Bob, 

Unfortunately, I don't have such a person in our group. I'm familiar with a pull-up resistor, but I wanted to know if there's any NI specific documentation for using one with an NI-9477. Looking a little more online I found this circuit diagram which makes more sense to me:

 

https://cdn.sparkfun.com/assets/6/f/b/c/7/511568b6ce395f1b40000000.jpg

Construction:

 

If I understand correctly, I can use the same voltage source, but will need multiple resistors, each connected between VCC (my 24V Power Supply), and a digital input. Then the power supply GND will connect to the NI-9477 GND (Pin 28) So for the fist few inputs I would have
24V+ -> R1 -> DO0 (Pin 1) + Module Input 0

24V+ -> R2 -> DO1 (Pin 2) + Module Input 1

 

Operation:

As I understand, this circuit inverts the logic of the module so that the NI-9477 DO = TRUE will result in a False output. So I'll just need to invert the logic 1st.

0 Kudos
Message 4 of 11
(3,950 Views)

@crossrulz wrote:

I think I would just invest in a NI-9476, which is a sourcing Digital Output (has Vsup input as the voltage source for all of the outputs).


Normally, I would, but this is one of those projects with more time than funds. So I'm in a work with what I have situation. 

0 Kudos
Message 5 of 11
(3,941 Views)

 Here's some ideas on driving 24V devices with your DIO... 

 

LED Driver.jpg

========================
=== Engineer Ambiguously ===
========================
0 Kudos
Message 6 of 11
(3,935 Views)

@RTSLVU wrote:

 Here's some ideas on driving 24V devices with your DIO... 

 

LED Driver.jpg


Thanks for the designs. However, these look more complicated than what the other diagram I posted looked like. Is what I posted earlier the "open collector," option? Is there a reason to use the MOSFET or Bipolar designs over this one?

0 Kudos
Message 7 of 11
(3,926 Views)

@JScherer wrote:


Thanks for the designs. However, these look more complicated than what the other diagram I posted looked like. Is what I posted earlier the "open collector," option? Is there a reason to use the MOSFET or Bipolar designs over this one?


Well most common DIO devices can't handle that high of voltage directly and this is how to make them do it

========================
=== Engineer Ambiguously ===
========================
0 Kudos
Message 8 of 11
(3,924 Views)

@RTSLVU wrote:

@JScherer wrote:


Thanks for the designs. However, these look more complicated than what the other diagram I posted looked like. Is what I posted earlier the "open collector," option? Is there a reason to use the MOSFET or Bipolar designs over this one?


Well most common DIO devices can't handle that high of voltage directly and this is how to make them do it



Ok, Thank you for the clarification.

Just to make sure, the NI-9477 looks like it can handle up to 60V input:
https://www.ni.com/pdf/manuals/374182b_02.pdf 

 

For my case (24V) Will I be able handle the voltage directly?

 

Just want to make sure, again for my background: I'm an ME, pretending to be an EE 🙂

0 Kudos
Message 9 of 11
(3,900 Views)

Hi JS,

 


@JScherer wrote:
Just to make sure, the NI-9477 looks like it can handle up to 60V input:
https://www.ni.com/pdf/manuals/374182b_02.pdf 

 

For my case (24V) Will I be able handle the voltage directly?

 

Just want to make sure, again for my background: I'm an ME, pretending to be an EE 🙂


It does not "look like"!

It is specified to handle an external power supply of 0…60Vdc, and it is specified to be able to switch upto 1A per channel with a max of 20A for the whole module…

Best regards,
GerdW


using LV2016/2019/2021 on Win10/11+cRIO, TestStand2016/2019
0 Kudos
Message 10 of 11
(3,886 Views)