Distance Application Notes
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.
Potentiometer Input Circuit
No additional components are required. Input pins 2
(Channel 1), 3 (Channel 2), and 4 (Channel 3) can be used
Conversion of Rotary Angle to
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
Setting up a Rotary Distance
channel using the OmniLog Software
Connect the GP-HR logger to a computer and Run the OmniLog
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)
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.