Use myRIO-1900 with mcp41100 digital potentiometer

[Beslie]

I looked at the "Digital Potentiometer" chapter of the "NI myRIO Project Essentials Guide and was trying to use the mcp41100 in place of the other digital potentiometer they used and it's not working. Can someone tell me what I'm doing wrong please?

This is my setup.

[Bob_Schor]

Pictures of wiring and circuit diagrams are OK.  Pictures of LabVIEW code are useless.  Please attach the LabVIEW Project (right-click the myRIO Project folder, "Send to", "Compressed (zipped) Folder") to your reply.  Be sure to indicate the version of LabVIEW and the myRIO Software Toolkit you are using.  Note that I suspect very few users are using a version more recent than LabVIEW 2019, with the corresponding 2019 Toolkit.

Bob Schor

[Beslie]

I used the Digital Potentiometer from the NI MYRIO PROJECT ESSENTIALS GUIDE. But I'll attach the files here as well for you to see.

[Bob_Schor]

The drawing you show where you indicate three wires you connected shows the actual wired connection for the PmodDPOT, not the mcp41100.  Mis-wiring the hardware could easily explain why you don't see your chip behaving as you hope.  You also illustrate only 3 wires, leaving out "Chip Power" (J1/GND and J1/VCC) and the "measuring circuit" connections (+5V, GND, and AI0).

Check your wiring.  If you are going to post a picture of what you are doing, be sure to illustrate it with the Chip you are actually using!

Bob Schor

[Beslie]

Sorry about that, would this be more acceptable. The image on the left is how I wired it along with the table describing each connectors details.

 

[Beslie]

He's a better photo, I also made an illustration on how I wired it.

 

[Bob_Schor]

The "too-small picture of the myRIO from another source that used a different digital potentiometer and showed that the code worked" is not useful.  A list (from you) of "I wired pin 1 of the mcp41100 to pin x of connector y of the myRIO" would be better, and honest.

Bob Schor

[Beslie]

Here's a list format for where each item is connected. I also attached the image below so that it can be downloaded and viewed at it's proper image size. Thanks a ton in advance.

PINS	NAME	FUNCTION	CONNECTED TO ON myRIO
1	CS	Chip Select	A25 – SPI.MOSI
2	SCK	Serial Clock	A21 – SPI.CLK
3	SI	Serial Data Input	A11 – DIO0
4	VSS	Ground	A6 - GND
5	PA0	Terminal A Connection For Pot 0	A1 - +5V
6	PW0	Wiper connection For Pot 0	B6 - GND
7	PB0	Terminal B Connection For Pot 0	B3 - AIO
8	VDD	Power	B1 - +5V