DAQ Factory interesting Crash, cant figure out the issue!

[JonP]

I am running DAQ Factory to measure air quality data, using a pump running through a labjack setup. When normally running my program DAQ Factory collects data as normal and the sensors seem to be working fine on their measurements, however, when I switch the pump on one of two different crashes have happened so far: The pump turns on and off briefly, then the whole computer and monitor shut off; The pump and computer stay running, but no out put is displayed onto the monitor and the data stops being collected. After checking many components of my setup and testing certain situations, I am inclined to believe that there is a software issue rather than hardware. The crash log is just and unexpected quit message with an unknown error. Has anyone experienced this problem, or has any insight as to what might be happening? 

[JonP]

For reference, my temperature sensor, pH monitor, both CO2 monitors, filter monitors, and valve actuator are all working correctly, it is only when running the pump does the issue start.

[AzeoTech]

How do you have the pump connected to the LabJack?

[AzeoTech]

Almost certainly what is happening is you are overloading the LabJack, probably because you have the power to the pump coming directly from the LabJack.  It has to go through a relay.  So, the LabJack is getting overloaded and which in turn brings down the USB bus.  Then depending on how hard the USB bus dies, either you just lose the LabJack (and thus the pump switches back off), or you crash out the whole computer.

I have also seen this happen with a system where the pump (or in the case I am thinking, a valve) was wired correctly through a relay, but the computer and said valve were on the same power supply.  When the valve switched, it would pull the voltage down on the PS and cause the computer to reboot.  The installer should not have used the same power supply for the computer and the valves.

[JonP]

I was originally steered away from a voltage issue due to the fact the computer does not crashes every time. The voltage for the pump is powered to the computer through a voltage divider into the NO port on the relay, and the COM port is wired to the LabJack which is connected to the computer through a usb connection. I am not sure how exactly Im supposed to wire this on a separate power supply as it is going to need to be portable and running off a 12V battery. I have also confirmed it not to be a memory issue during data collection. 

[JonP]

Here is an image of the wiring schematic for reference. 

[JonP]

This is the power supply schematic

[AzeoTech]

I reread your original post and I'm not clear on what exactly is happening.  You say:

Quote

The pump turns on and off briefly, then the whole computer and monitor shut off; The pump and computer stay running, but no out put is displayed onto the monitor and the data stops being collected. After checking many components of my setup and testing certain situations, I am inclined to believe that there is a software issue rather than hardware. The crash log is just and unexpected quit message with an unknown error. Has anyone experienced this problem, or has any insight as to what might be happening? 

Correct me if I am wrong:

The first failure mode is that the computer and monitor shut off completely.

The second failure mode is that the computer monitor just goes blank but the computer appears to still be powered up (LED and fans I'm assuming is how you tell)

It is pretty far fetched for either of these failures to be software related.  Windows does a lot to encapsulate user level software so that one piece of software can't crash the whole machine.  Nowadays you rarely even get blue screens, and those are almost always caused by hardware failures or bugs in hardware drivers (which are kernel level, not user level like DAQFactory).

I still think you have a problem with how you are powering things.  The pump looks ok, though I don't know why you need 5V to the relay board unless you are sinking your relay.  But the secondary question is how big is your relay, and what is the inrush on it.  I'm assuming it is mechanical and not solid state.

Then you also have other things that are being powered from the LabJack, like the steppers.  I don't see why you are pulling 5V off the LabJack when you have 5V at your power supply.  USB 2.0 has a limit of 0.5 amps on the port, usually.  This is real easy to exceed with inrush.  You can rate all your stuff and it will appear that you are under 0.5 amps, but when that coil fires, or your stepper starts moving, the actual current being pulled is quite a bit higher than the rating, if only for a very short bit.  This is exactly what happened in the story I told in the earlier post about the power supply being pulled down.  The installer had rated the power supply based on the running current ratings for the various devices, but forgot about inrush.  So, when the valve started turning, the current load would spike.  The power supply couldn't supply it, so it had to drop the voltage to achieve it (think brown out).  Like your case, this didn't happen every time.  It depended on what else happened to be running at the same time.  Even the computer itself uses varying amount of power depending on CPU usage, etc.

 

[LabJackSupport]

We would tend to agree with Azeotech that you are more likely seeing a hardware related issue. Here are some other things to consider.

Generally we recommend troubleshooting by running tests that isolate each potential source of the issue. Do you have any way to reasonably test your software without devices such as the pump and DC motors/controller connected? Even better, could you set up a test without anything connected besides a computer and LabJack, for example by setting up the DAQFactory program on a different computer elsewhere? We understand that this might not be possible depending on your control system setup, but either situation should help test whether the issue is in software since it eliminates the most likely hardware that could be causing issues.

It looks like you may have ground loops in the wiring setup. The LabJack GND should be common to laptop GND through the USB connection. It looks like both the laptop and labjack GND are connected to screw ground, which could set up a ground loop. It also looks like multiple LabJack GND terminals are referenced to screw ground in multiple locations. We would suggest trying to reduce the number of ground connections. Ideally, LabJack GND should only be referenced to your screw ground in one location (if at all). We would suggest trying to eliminate these potential ground loops, and if possible isolate the LabJack/laptop from the pump and DC motor systems. That would help ensure that things such as inrush/flyback are not wiping out the USB interface or laptop more generally.