SHT15 timing/programming

[n1ivy]

Here is the DAQfactory file for measuring probe conditions. There are four on board sensors and each sensor has a heater, an RTD and a gas sensing film. The four sensors are located on a board along with an SHT15 temperature and humidity sensor. When the SHT15 runs the signals from the gas sensing films are noisy. It looks like it may be a timing issue to me. I'm not a very good with programming so I think the program may be the problem, but I'm not sure. Can you take a quick look at the code to see if I have made any mistakes? The reading rate from the SHT sensor can be slowed if needed.

Thanks

keck_probe_pwm.ctl

[AzeoTech]

The LabJack folks will have to address the actual commands being sent to their devices. The only comment I have is that you don't have any delay() inside your while() loop. You should pretty much always have some sort of delay(), of at least 0.01 seconds. There are cases where you wouldn't but this is not one of them. The delay() in your case should probably be whatever your desired data interval is (say 1 for a reading once a second)

Now, the SHT reading may block while it reads, creating a delay in your loop. However, if there was ever an error and the SHT reading returned right away, you'd have a loop running at high speed using up your processor power.

[n1ivy]

I have installed a delay in the SHT sequence and it seemed to run ok for awhile. I have added a digital out to page and started monitoring the U6 board temperature using the built-in channel 14 temperature sensor. now I see noise on the resistance measurement screen and the channel 14 temperature sensor.

keck_probe_pwm032311.ctl