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GP-HR Rotary Distance Application Notes
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Any combination of the three analogue inputs of the GP-HR Logger can be configured to read potentiometers. We recommend the use of 10k to 100k potentiometers. If an  arm is attached to a rotary potentiometer the linear distance the arm moves through can be logged by the GP-HR. This application requires a linear potentiometer.  

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Potentiometer Input Circuit

No additional components are required. Input pins 2 (Channel 1), 3 (Channel 2), and 4 (Channel 3) can be used

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Conversion of Rotary Angle to Distance

The channel attached to the rotary potentiometer is set to Rotary Distance in the Omnilog software. The software converts the rotary angle read from the potentiometer to a linear distance. The system must be used over any 90° quadrant of the potentiometer. A linear potentiometer must be used for this application

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Setting up a Rotary Distance channel using the OmniLog Software

Connect the GP-HR logger to a computer and Run the OmniLog software

From the Logger Control Screen select Channel and Probe Setup

Select Channel 1 to 3 (These are the analog input channels)

From the Probe box select the Rotary Distance option as shown
(This will require Omnilog Version 1.30 or greater)

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Notice that after the Rotary Distance probe has been chosen the Units in the Unit and Scaling box has been set to mm

Now give the Channel a meaningful Long and Short name in the Logger Channel Name box.

The system must now be calibrated.

Connect the linear potentiometer, with arm, to the logger

Enter the required Units in the box marked Units
This will normally be mm for millimeters or in for inches

Set the arm so that it is in the start position or 0 distance

Click on the First Point Button

Set the arm so that it is at 90° to the start point

Enter the Linear Distance that the arm has swung through into the Box marked Second   Point. This will be the same as the length of the arm.

Click on the Second Point Button

Notice that new calibration offset and gain figures have been calculated and the distance you entered is now in the Scale Gain Box.

Click on the Write Unit, Scaling and Calibration values to the Logger button to send the new settings to the logger.

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