Cleveland Motion Controls Classic Series DIN Rail Amplifier with Isolated Output MWI-13467 REV CA - Manual (Page 27)

MAN-13467 R EV CA C LASSIC S ERIES A MPLIFIER W / I SOLATED O UTPUTS
Page 27 of 30
3.9 A DJUSTING A MPLIFIER C OARSE Z ERO
A coarse offset adjustment has been provided. Keep in mind that the Coarse Zero adjustment is usually only
adjusted one time, typically when the amplifier is installed, or transducers are replaced.
1. Ensure that the IA gain setting has been set as described in section 2.5.
2. Set the Zero pot on the front cover to mid-way (approximately 9 turns from either clutch actuation).
3. Set the Gain POT from fully counter clockwise.
4. Connect a DC Voltmeter to inspect the +/- 10 VDC output signal for the “Zero”
condition (NO calibration force on the transducers).
5. Adjust the coarse POT (P5) to achieve the desired “Zero” voltage. As this is a coarse adjustment, a voltage
within 50 millivolts of the intended “Zero” should be adequate.
3.10 G AIN A ND F INE Z ERO C ALIBRATION
Use the following steps to make your final calibration adjustments:
1. Verify Zero on the analog Outputs for the “unloaded” condition and adjust the (Fine) Zero POT to correct
for any minor offset voltage.
2. Apply the calibration force to the transducer(s) and adjust the Gain potentiometer to achieve the desired
span.
3. Verify linear operation of the transducer and amplifier by applying a force that falls somewhere between
the zero and full-scale endpoints. The intent is not to conduct any calibration per se, but to confirm the
hardware’s ability to accurately report a measured force.
When conducting calibration that involves a large mass, it is often practical to use a series of smaller masses added
in succession. In such cases an initial Zero and Gain adjustment should be done when the first 20% of the weights
have been applied. When the full calibration load is applied, only minor adjustments should be required.
In setting the amplifier gain, we recommend that you focus only on achieving a particular voltage “span” between
the load and unloaded forces by alternating between the two force levels. Avoid repeatedly adjusting the Zero POT
between measurements unless the offset voltage becomes excessive and interferes with achieving a valid analog
output signal. You should only adjust the final Zero after the desired Gain setting has been achieved.
These final calibration steps represent the minimal adjustments that might be required at periodic calibration
intervals and
typically involves only the Zero and Gain potentiometers accessible through the small holes in the
front cover.