Jul 06

Pulse/Frequency Splitter Circuit

I was working on a project recently where I needed to take a single frequency output from a liquid coriolis meter and split the signal into two identical signals. One of the signals needed to go to a flow computer to calculate the flow of oil going through the coriolis meter and the other signal needed to go to a prover connection so the meter can be proved periodically.

Apparently, the pulse or frequency signals used for the meter and the prover connection have to come from the same signal generator in the meter and the meter only had one pulse/frequency output. The frequency from the coriolis meter needed to be 10,000 pulses per barrel, or 10kHz.

We ended up using a PE-100 Liquid Sample System Interface made by Angus Measurement Services, LP. It was a simple, off the shelf solution that worked. The PE-100 can do several things and is designed to not only split a pulse or frequency signal, but it also has a relay output to send pulses to a sampler solenoid. I think it might have been overkill for this project, but like I said, it was a simple, off the shelf solution.

This got me thinking though. I was wondering how hard it would be to make a simple pulse/frequency splitter that is accurate. One that could essentially take a single signal in and split that signal into two identical signals without losing any of the original signal’s integrity, thereby maintaining the accuracy of the original signal.

Turns out, not only was this a pretty simple task, I already had the parts to do it in my shop. I wanted the splitter to be powered from a 12vdc or 24vdc power supply since both voltage levels are readily available in most liquid measurement control cabinets. The splitter also needed to be small in size, and as I said before, accurate. I wanted the splitter to be able to handle anything from 1Hz up to 20kHz – one pulse per barrel up to 20,000 pulses per barrel.

What I ended up with was a splitter that can operate from about 8vdc up to 30vdc, splits almost any shape of waveform into two identical signals, and works accurately from 1Hz up to about 30kHz. My splitter works well between 20% and 90% duty cycle. The sweet spot seems to be between 25% and 75%.

It draws between 30mA and 36mA depending on the supply voltage, amplitude of the output signals, and ambient temperature. I used several methods to test the splitter, but as a final test, I connected both output signals to an ABB Totalflow XRC motherboard on two pulse inputs. Normally, a Totalflow XRC pulse input needs at least 6vdc of amplitude to register a pulse signal. I found that my splitter needed the input signal to have an amplitude of at least 7vdc to output two signals correctly. The splitter dissipates about 1vdc of the input signal amplitude. This should not be a problem though.

Overall, this was an interesting side project. I learned a few things about signals and had some fun with it. As you can see from the pictures below, I developed the splitter circuit on a breadboard, then built the circuit on perf-board. Finally, I drew the circuit in CAD. Maybe someday I’ll send the files to a fab shop and have some of them built.

Breadboard

Breadboard Picture

Proto-board

Proto-board Picture

1Hz Signal
1Hz Signal

10Hz Signal

10Hz Signal

1kHz Signal

1kHz Signal

10kHz Signal

10kHz Signal_1

30kHz Signal

30kHz Signal

Pulse Inputs at 1kHz

PI_1kHz

Pulse Inputs at 10kHz

PI_10kHz

Pulse Inputs at 17.295kHz

PI_17295kHz

Pulse Inputs at 30kHz

PI_30kHz

PCB Layout

PCB

3D View of PCB

Pulse_Splitter_3D

I hope you found this interesting. If so, please share it.

Jan 13

Crimson 3.0 Won’t Load on Windows 10

Like millions of others, I recently upgraded my PC to Windows 10 and found that some of the software I use, such as Red Lion Controls’ Crimson 3.0 doesn’t work right anymore. Some software applications show problems presenting data and/or configuration settings when actively programming or configuring a device, while other applications are just buggy now. In the case of Crimson 3.0, I could never get past the splash screen. The photo below shows the problem I was having when I opened Crimson 3.0. For the record, this doesn’t seem to be a problem with Crimson 3.0 or any of the other software applications I found this or similar problems with. It seems to be a problem with Windows 10 drivers. I’ll tell you why I think this is a Windows 10 issue a little later.

Crimson 3.0 Splash Screen Picture

Crimson 3.0 Splash Screen

As you can see, the application opens but the splash screen never goes away. It stays on top of the application’s main interface and maintains the focus of the display. You can’t even close the splash screen or use the application in any way until that splash screen is dealt with, and there is only one way to deal with it. The only thing you can do is close the application using the Task Manager in Windows.

Windows 10 Task Manager Picture

Windows 10 Task Manager

From the picture above, you can see that Crimson 3.0 shows up in Windows 10 Task Manager as Shell Application. Select “Shell Application” then click on the End task button on the bottom right side of the window. This will close Crimson 3.0 so you can move to the first step in fixing the problem.

Open the Device Manager in Windows 10. You can get to the Device Manager by holding down the Windows key on your keyboard and pressing the “X” key at the same time, then select Device Manager or press the “M” key. When the Device Manager opens, look for the section that says “Human Interface Devices” and expand it.

Human Machine Interface Picture

Windows 10 Device Manager

Once you expand the Human Interface Device section, you should see “HID-compliant touch screen” in the list, as in the picture above. Right click this and select “Disable” from the context menu that pops up. See the picture below.

HID-compliant touch screen picture

Disable HID Touch Screen Driver

Windows will prompt you with the message below. Click Yes.

Are you sure picture

Yes You Are Sure

When the driver is disabled, the icon will look like the picture below.

After Disable Picture

After Disabling HID Driver

And finally, once you’ve disabled the HID-compliant touch screen, Crimson 3.0 should open normally. The only problem with this work around is that you’ll have to enable the HID-compliant touch screen again to use your PC’s touch screen. This brings me back to the statement I made above, where I said I don’t think this is a Crimson 3.0 problem or even a problem with whatever software application seems to be giving you a similar problem after upgrading to Windows 10.

Before I upgraded to Windows 10, I had Windows 8.1 and my PC had the same touch screen. I never had this problem or many similar problems while using Windows 8.1 with HID-compliant touch screen enabled. This only started after upgrading my PC to Windows 10. If your PC doesn’t have a touch screen, you probably won’t see this problem either. However, many companies and Technical people are beginning to use Windows 10 and many of the PCs that are already running Windows 10 have touch screens so the machine can be used like a tablet. Hopefully Microsoft will fix this bug soon so we don’t have to work around it. Don’t forget to enable the HID-compliant touch screen when you want to use your PC like a tablet. If you find this or a similar problem, please tell us about it in the comment section below. I hope this helps.