Kaman KD-2300 - Manual (Page 28)

KD-2300 Instruction Manual Part IV: Calibration
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25
Calibration Controls
You will need to calibrate each measuring channel in your system using the
Zero, Gain, and Linearity (Coarse and Fine) potentiometers located on the
control end of the module. The controls rotate both clockwise and
counterclockwise through the use of a small screwdriver or the supplied
calibration tool.
A description of each calibration control follows:
Clockwise rotation of calibration controls causes the analog output to go more
positive; counterclockwise causes more negative output. If you turn a
potentiometer in the same direction (clockwise / counterclockwise) until you
see no change in system output, you have reached a limit of that particular
control. If this occurs, your options are: 1) change the gain by changing the
gain jumper (APPENDIX B); 2) check for excess loading around the sensor, or
3) make sure that your target size and material are appropriate (Part 3:
EQUIPMENT).
Zero Control
The Zero control lets you set an electrical zero point. As illustrated in the diagram, the
Zero control adjusts the point at which system output intercepts the x-axis.
After calibration, you can use the Zero control to shift system output anywhere from
40-60% below the x-axis, depending on sensor, sensor mounting and gain. This feature
is useful in applications where you need a +/- deviation from a standard, or when signal
conditioning electronics require a bipolar output, such as with an A/D converter.
The Zero control is particularly useful in “zeroing out” any mechanical offset created
when you move from a simulation to an application fixture. You can also use the Zero
control to correct for the small amount of drift that can occur over a period of time
through aging and temperature change. This slight drift is easily corrected using a
master target or dimensional standard and readjusting the zero shift until the desired
output reading is attained.
ZERO
INITIAL CALIBRATION
ZERO
AFTER CONTROL
ADJUSTMENT
TARGET
DISPLACEMENT
+O
U
T
P
U
T
-OUTPUT