In your Control Panel, double click on "Quadrature Encoder Phidget":

Before you open a Phidget channel in your program, you can set these properties to specify which channel to open. You can find this information through the Control Panel.

1. Open the Control Panel and double-click on the red map pin icon:

2. The Addressing Information window will open. Here you will find all the information you need to address your Phidget in your program.

See the Phidget22 API for your language to determine exact syntax for each property.

In the Phidget Control Panel, open the channel for your device and click on the icon next to the data type that you want to plot. This will open up a new window:

If you need more complex functionality such as logging multiple sensors to the same sheet or performing calculations on the data, you'll need to write your own program. Generally this will involve addressing the correct channel, opening it, and then creating an Event Handler and adding graphing/logging code to it.

The quickest way to get started is to download some sample code for your desired programming language and then search google for logging or plotting in that language (e.g. "how to log to csv in python") and add the code to the existing change handler.

The Change Trigger is the minimum change in the sensor data needed to trigger a new data event. The Data Interval is the time (in ms) between data events sent out from your Phidget. You can modify one or both of these values to achieve different data outputs. You can learn more about these two properties here.

The ENC1000 can connect to any of the encoders we sell without any modification just by setting the IOMode property to Push-Pull . If you are trying to use your own encoder, you may need to change the IO mode to Open Collector or Line Driver mode. See the Encoder Primer for more details on what to use.

The encoder input on the ENC1000 uses a 5-pin, 0.100 inch pitch locking connector. The connectors are commonly available - refer to the Table below for manufacturer part numbers.

Note: Most of the above components can be bought at Digikey.

When your program captures an encoder change event, it will receive two variables: positionChange (measured in 'ticks', four of which equal one quadrature count for the ENC1000) and timeChange (measured in milliseconds). You can use these values to easily compute the instantaneous velocity of the encoder. For example, our C# encoder example implements this method of velocity calculation:

void enc_change(object sender, Phidget22.Events.EncoderEncoderChangeEventArgs e) {

...

// Convert time change from milliseconds to minutes
double timeChangeMinutes = e.TimeChange / 60000.0;
// Calculate RPM based on the positionChange, timeChange, and encoder CPR (specified by the user)
double rpm = (((double)e.PositionChange / CPR) / timeChangeMinutes);

...

}

This implementation may be useful if you are graphing the RPM on a line graph, but if it's being used to display the current RPM as a single number, it won't be very helpful because when the motor changes speed or direction frequently, it'll be hard to read the velocity as a meaningful value. This method can also be prone to variations in velocity if the encoder's CPR is low and the sampling rate is high. To solve these problems, you should decide on a time interval during which you'll gather data, and take a moving velocity calculation based on that data. You can use the Queue data type to make this easy:

Queue<double> positionChangeQueue = new Queue<double>();
Queue<double> timeChangeQueue = new Queue<double>();

void enc_change(object sender, Phidget22.Events.EncoderEncoderChangeEventArgs e) {

double totalPosition = 0;
double totalTime = 0;
int n = 500; // sampling window size, duration is 500*t where t is the data interval of the ENC1000

// add the newest sample to the queue
positionChangeQueue.Enqueue(e.PositionChange);
timeChangeQueue.Enqueue(e.TimeChange);

// If we've exceeded our desired window size, remove the oldest element from the queue
if ( positionChangeQueue.Count >= n ) {
     positionChangeQueue.Dequeue();
     timeChangeQueue.Dequeue();
}

// Calculate totals for position and time
foreach( double positionChange in positionChangeQueue ) {

     totalPosition += positionChange;
}

foreach( double timeChange in timeChangeQueue ) {

     totalTime += timeChange;
}

// Convert time change from milliseconds to minutes
double timeChangeMinutes = e.TimeChange / 60000.0;
// Calculate RPM based on the positionChange, timeChange, and encoder CPR (specified by the user)
double rpm = (((double)e.PositionChange / CPR) / timeChangeMinutes);

}