Phidgets Forums

Is there a way to get basic product info from the libs for a given Phidget product? For example, min & max allowed data interval, min and max allowed sensor values, formula, etc.

So for example, for a 3502 Current sensor, I would get back something like:

• Product: SENSOR_TYPE_3502
  Formula: (voltage / 0.1, 4); // RMS Amps'
  Max input value: (sensorValue < 50.0)); // RMS Amps',
  Unit: PHIDUNIT_AMPERE
  Plus anything else

BTW, thanks to Patrick I now know where this info is located for regular analog/voltageRatio sensors. But, I was wondering if there was a way to get it dynamically.

Thanks

You might be able to get the "Product" line from iterating on the VoltageSensorType and VoltageRatioSensorType enums (although I don't know how to do this in python).

The formula is baked into the libraries in the file that Patrick showed you, and it's not exposed in the API so I don't think you can get it.

The unit could possibly be grabbed by calling getSensorUnit after setting the sensor type but that seems like a pain.

I have to say, I'm getting curious as to what kind of program you're writing based on the questions you're asking. A custom Phidget Control Panel of some sort?

I am writing a plug-in for the Indigo home automation system. https://www.indigodomo.com/

I did one for Phidgets21 several years ago and am finally getting around to doing one for P22.

… and thanks for the response. The key info I need is the unit (fir data presentation) and range (for configuration validation), and I have already scraped that from the source. I was just wondering if there might be a better way to get it.

And, a follow-on question. For voltage and voltageRatio devices connected to standard (non-VINT) ports, is it possible to getSensorUnit() before the device has a sensor change trigger event. Example. I open a current sensing phidget on a circuit that is currently off. I would like to know the sensorUnit will be "ampere," and, indeed, if I wait for a sensor change event I will get that information. But, I would like to get it earlier. If there were a way to force a sensor change event, that would be perfect. But, I can't find it. Calling getSensorUnit() before the first sensor change results in... I know this information is available in the libs as previously discussed. But, if there were a way to get it from the device, that would be much cleaner.

If you set your sensor type in the attach handler, then the initial event will initialize the sensor unit/value. As long as the initial value is in range of your sensor - you will always get an initial sensor event after attach.

Also, any time you change the sensor type, the library sends a sensor event right away, so you can listen for that event.

-Patrick

Perfect!