How precise is Phidget intervals when raise Phidget22.Events

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PatrikMichnac
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How precise is Phidget intervals when raise Phidget22.Events

Postby PatrikMichnac » Fri May 24, 2019 4:49 am

Hello, I have 4x Thermocouple Phidget with VINT Hub Phidget. I have a question regarding termometer intervals. I can set intervals from 20ms to 1000ms. First of all, I want to know which device has a clock and which device is responsible for timing. It is Thermocouple or VINT HUb device? And secnd question is how precise is this clock. Do you recomend to use computer timer to control timing or is it possible to count miliseconds from intervals? I want to save value from termocouple every seconds so I just want to know if better approch is to use windows timer or can I be sure with interval precise and than I can use clock on Phidget?

fraser
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Re: How precise is Phidget intervals when raise Phidget22.Events

Postby fraser » Fri May 24, 2019 9:03 am

I wouldn't rely on intervals for precise timing. They are pretty accurate on their own, but when coming down through the library and program, the accuracy will drop. Program event times vary (especially if used in a GUI scenario, where there's generally 10ms of overhead), so you're best off using timing from the OS.

I've seen event times vary +/-5ms to +/-10ms on random data points in C# GUI applications. But in general the average time between events will be what you specify as a DataInterval.

But to answer your question it is the TMP1101 that handles timing, and if running 4 thermocouples at minimum DataInterval, you could see the intervals go up due to high load.


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