Monarch Tachometer Sensor

[KowdTek]

Hello, I have a monarch infrared optical  sensor that I need to configure.

The signal is +V to 0 vdc pulse and the speed range is 1-1,000,000 RPM.

The actual output based on the spec is 0-5vdc.

Any help will be appreciated... Thanks!

[Luke_G]

Hi pbha,

From the specifications that I found on monarchinstrument.com, it looks like this device gives a TTL output, which is ideal for counter applications.  Any device with two counters would be able to measure this signal.

If you are looking for help with the programming, there are useful resources on ni.com.  I recommend that you look at "Building a Counter Input" which is part of Getting Started with DAQmx Programming in LabVIEW.

Let us know if you have further questions.

[KowdTek]

Luke,

Thanks! I made it work but using another monarch instrument which gives me a very straight forward output (0-5vdc).

I will try to program it just by itself.

Thanks again.

[KowdTek]

Still can't get it to work (just the sensor + LabView) All I get is counting numbers not the actual tach value. I guess counter application confuses me. 😞

[Luke_G]

Hi pbha,

What are you trying to measure? (Frequency, position?)

What have you tried so far? Was the link I pointed to for "Building a Counter Input" relevant?

Most importantly, what data acquisition device are you using?

[KowdTek]

I want to measure speed, you are right any device with double counter could read this sensor's signal and I was able to build the VI using both.

But I'm having trouble if I just use the sensor knowing the output is TTL 5-0Vdc which is I'm not familiar of. Btw, I'm using PCI-6024E and BNC -2110

breakout box.

Thanks for your time.

[Luke_G]

Hi pbha,

I recommend that you take a look at the example programs that install with LabVIEW.  You can open the Example Finder in LabVIEW under Help>>Find Examples...

I suggest that you browse by task to Hardware Input & Output>>DAQmx>>Counter Measurements>>Digital Frequency

For your application, I would start with Meas Dig Freq-Buffered-Cont-Large Range 2 Ctr.vi

Please let us know if you have further questions.

[Team Stoney]

Hardware

cDAQ NI 9172

Module: NI 9401

Monarch Instrument’s Remote Optical Sensor (for measuring RPM/pulse counts)

Software

NI Sound & Vibration Toolkit

NI Signal Express

LabView

Experience Level

Beginner

My objective is to read and record accelerometer and engine speed data together so they are time stamped the same.  Setting the accelerometer up was easy… the RPM, not so easy.

I have been trying to convert a 5v TTL signal from an optical sensor (SPS-5), which is used to measure RPM, in NI Sound & Vibration Toolkit.  The optical sensor is a stand alone, self powered system with a output signal of “TTL compatible pulse (0 to 5VDC)”.

I’ve started a project in NI Sound & Vibration Toolkit, “Add Step”, “Acquire Signal”, “Digital Input” and “Line Input”.  On the Step Setup Tab/Configuration Tab, I’ve selected my channel, Acquisition Mode set to Continuous Samples, Rate set to 1.3kHz.  Then on the Step Setup Tab/Advanced Timing I had to select “On Demand” for Sample Clock Type due to error message(s).  “On Demand” is the only way to get the signal to appear on the Step Setup Tab’s graph.  The signal is a square wave represented by 0 and 1 (0s and 1s are overlaid on the graph).  When I block the optical sensor view, the signal goes flat represented by 1.

I’ve also messed around “Acquire Signal”, “Counter Input” and “Edge Count” with the same results.

I just can’t seem to NI software to display that TTL signal in RPM numeric display.

I’ve even changed the TTL (digital signal) to an analog signal.  I can see them Step Setup tab.

Have you had any luck with yours?

[KowdTek]

Here's what've I got and it works for me.

[Robert_F]

Hello Team Stoney,

Is your TTL signal from optical sensor producing a frequency measurement which corresponds to RPM?  Or is your sensor producing a PWM signal which corresponds to RPM?  Since you are new to LabVIEW, I would suggest using the DAQ Assistant under the DAQmx palette. Once you configure the DAQ Assistant to acquire your signal, you can test your settings and generate DAQmx code.  (Right-click on the DAQ Assistant after you are finished configuring it and select Generate NI-DAQmx Code)

FlipTek has a really good idea of converting a frequency measurement into RPM.  However, I would strongly encourage you to use one while loop instead of two.  The inside loop will only run once or forever.  There is no other way stop the while loop.  Here is FlipTek’s example slightly modified.  It uses one while loop and measures frequency instead of period.

Message Edited by Robert F on 09-17-2007 11:00 AM