Electronic installation – Max Machinery 234 Flow Meter User Manual

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Electronic Installation

When to Calibrate

Calibration should be performed under the following conditions:

1 . If the circuit board of the transmitter is changed .

2 . If the connector between the pickup coils and the circuit board is reversed .

3 . If it is suspected that the output signal contains more frequency modulation than it should have . (i .e .: Pulse
widths vary by more than ±15%, and variations are not random, but cyclical at 4 times per revolution)

Calibration Procedure

1 . Set up a steady flow rate through the meter that results in a meter rpm between 20 and 500, ideally
somewhere around 100 rpm . The position indication LED’s in the center of the circuit board can aid in rpm
determination (i .e .: at 100 rpm, each light will blink 10 times in 6 seconds) .

2 . Rotate S3 to the ‘0’ position to enable calibration .

3 . Press the ‘CAL’ button, S5 . If the ‘SLOW’ LED (D8) comes on, wait 10 seconds for it to go off, increase the
flow rate and try pressing the ‘CAL’ button again .

4 . Wait for the ‘CAL’ LED (D9) to stop blinking and turn back off . While the calibration is active, the position
indication LED’s in the center of the board will pause . As soon as the calibration is complete, they will resume
activity .

5 . The calibration is now complete . Return S3 to the appropriate setting to get the desired number of output
pulses per revolution .