Siemens Milltronics MFA 4p Operating Instructions Manual page 24

Service and maintenance
5.1 Calibration
Overspeed
1. Set switch SW3 to Overspeed.
2. Set ppm switch SW2 to X 1 position.
3. Set ppm potentiometer fully CCW to 0.
4. Determine incoming pulse rate by slowly turning ppm potentiometer CW until Relay LED
2 goes on. Because the MFA 4p requires 2 pulses within range before energizing relays,
low ppm applications (e.g. 2 ppm) may require stepping of potentiometer at appropriate
time intervals.
5. If no response is obtained when you set the ppm potentiometer to 3, (below this stability
suffers), reset potentiometer fully CCW and set switch SW2 to X 10, and then X 1 if
required, and repeat step 4.
6. When Relay LED 2 goes on, indicating the incoming pulse rate, turn potentiometer CW
slightly past this point to obtain an operating setpoint that allows for normal fluctuations
due to load and voltage variations.
Note
If N.O. contacts were shorted as described in final note of calibration preamble, remove them
now as calibration is complete.
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Operating Instructions, 08/2017, A5E33988839_AB
Milltronics MFA 4p