Example VI for counting voltage pulses

[LabNoob14]

I'm trying to figure out the best way to set up a FP-Quad-510 to count voltage pulses first in MAX so I can learn what the appropriate channels/axis are. Then in LV2014 i will impliment some code to data log the count.

Do you know of any example VI's? I did a quick search and didn't come up with much of anything helpful.

[TimothyDug]

Hi LabNoob14,

Did you install the FieldPoint Driver yet? I linked version 15.5, but compatibility may differ depending on what version of LabVIEW you are using. Generally you want to match versions (so, LabVIEW 2014 would go with FieldPoint 2014).

Any examples we do have should be included with the FieldPoint driver, but this is admittedly an older product, so it may be difficult to track down other examples that are still maintained.

We've replaced FieldPoint with CompactRIO, and there is certainly more resources available for that platform. Would you be interested in talking with someone about those options?

Let me know if you have followup questions!

Thanks,

[LabNoob14]

Yes I've installed version 15.4 I believe(what-ever it is, it's the latest version that is still compatible).

I may not know enough about how the electronics to even plug the wires in the correct terminals lol...

So far I have yet to read any voltages in MAX from the QUAD-510. But I do just fine with the TC120s, AI-110 and DO-400.

The whole "signal, axis and channel description/type" has me confused I think.

All I want to do is read the voltage pulse from an outside source and count how many times it's been read.

I do have a cDAQ system, but it's currently on another project.

Thank you for your response!

[TimothyDug]

Hey there,

• So, for the basics of understanding the terminology and wiring, I would refer to a couple documents of ours.
  • The Encoder Measurements How-To Guide will explain the meaning of the different signals.
  • The FP-QUAD-510 and cFP-QUAD-510 Operating Instructions will explicitly talk about each pin.
• I'll try to explain the basics for brevity, but forgive me if I explain something you already know.
  • An axis will be one drive and motor.
  • A drive controls a motor by sending it signals.
  • And the motor is doing the physical motion.
  • So, assuming you are just controlling a single motor, you would only be concerned with Axis 0.
• As for the A +/-, B +/-, I +/-, 5 V, and COM pins, these are relatively common encoder pins. 
  • For A and B, an encoder with one set of pulses (e.g. only A) would not be useful because it could not indicate the direction of rotation.
  • Using two code tracks (e.g. A and B) with sectors positioned 90 deg out of phase, the two output channels of the quadrature encoder indicate both position and direction of rotation.
  • The I pin is the index pin. This is often called the Z line. You can use this single pulse for precise determination of a reference position.
  • The minus lines (e.g. A-, B-, I-) imply that you have differential lines, as opposed to single-ended. This means the signal will be cleaner at the cost of having more wires. Essentially, you just have two wires making up a single signal for the purpose of producing a cleaner signal.
• As for the channel descriptions, if you're only using one drive and motor, you would only be concerned with the Position LSB 0, Position MSB 0, Velocity 0, and Index 0. The two position channels would make up your 32-bit position. Does that make sense?

I hope this reply is helpful, but let me know if you have followup questions!

[LabNoob14]

Yes, this helps, I think it's starting to make sense to me.

But I don't want to control the motor I just want to read it's position as it rotates.

Gas flow is actually controlling the motor, I'm just using the motor to measure the amount of gas passing through it.

Am I using the wrong module to do this? Would an AI-110 work better just to read incoming voltages? Some how this seems like a less accurate way of measuring.

[LabNoob14]

I found out something new about the encoder.

I should be measuring resistance, not looking for voltage.

Now the question is, can the Quad-510 measure resistance? Is that what the Index channels are for?