Milltronics OCM II PL-269, Инструкция по эксплуатации

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RE-SCALING VELOCITY SENSOR INPUT
The OCM II velocity sensor input can be re-scaled to accept input signals other than 1-5 volts. Its range of
adjustment allows re-scaling of any input signal with voltages ranging between 0 and 10 V, but of a minimum
span of 2.5 volts.
Care must be taken to avoid inadvertently
adjusting the wrong zero or span potentiometer since there
are also zero and span adjustments associated with the
temperature sensor and with the analog current output circuitry.
1. Measure the reference voltage at pin 8 of IC22, it will be about 2 volts. Record the exact value.
2. Remove the sealing compound from ZERO pot, P4 and SPAN pot, P2.
3. Turn the ZERO pot fully CCW (counterclockwise), 20 turns.
4. Connect 0 to 10 volt DC source to the input terminals, TB1-16 (+) and TB1-17 (-).
5. Adjust the input voltage until it is equal to the proposed input SPAN. (ie. 3 volts for a 7-10 volt velocity
sensor input)
6. Adjust the SPAN pot, P2, until the voltage at IC33 pin 1 is exactly TWICE the voltage recorded in step 1.
7. Now adjust the input voltage to be equal to the SPAN (STEP 5) plus any OFFSET (e.g.: 3 volt SPAN
plus 7 volt OFFSET = 10 volt for 7-10 volt velocity sensor input).
8. Then adjust the ZERO pot, P4, until the voltage at IC33 pin 1 is once again TWICE the voltage
recorded in step 2.
9. Check that when the input voltage is adjusted through the desired input range, the voltage at IC33
pin 1 ranges from exactly zero to exactly twice the voltage recorded in step 1 (plus or minus 10 millivolts).
10. Record the new velocity input scaling and re-seal P2 and P4.
PL-269 9 – 8