Curtis Dyna-Fog 2742, Manual

Page: 47 / 84

TACHOMETER DECODE MODULE
The tachometer decode module senses the interruptions of the infrared sensor
located on the motor which drives the formulation pump.
The sensor is interrupted 40 times (the number of teeth on the sensing gear) with
each revolution of the pump. These pulses are amplif
i ed and fed into two
frequencies to voltage converters, one for low range and one for high range.
The low range converter generates 7.00 +/- .05 volts for each 88 interruptions per
second, and high range converter generates 6.50 +/- .05 volts for each 888
interruptions per second. On low range 7.0 volts is analogous to 1.8 ounces per
minute (54 ml/min) and on high range 6.5 volts is analogous to 18 ounces per
minute (540 ml/min).
The scale factors differ for high and low ranges in order that the characteristics of
the pump can be more closely approximated.
PIN FUNCTION DESCRIPTION
1 Instrument ground Provides reference to voltmeter in remote box which
is free of heavy current flows that can cause errors in
readings.
2 High overrange
Causes fault light circuit in motor control to be activated
in motor overspeeds due to excess command or break
lock condition 0 to 8.5 V DC.
3 Ground
Ground input for module.
LOW CONTROL FEEDBACK
HIGH INSTRUM. OUT
HIGH CONTROL FEEDBACK
-4 VDC OUT
HIGH OVERRANGE OUT
LOW INSTRUM. OUT
+ 10 VDC IN
+5 VDC IN
GROUND INPUT
INSTRUM. GROUND
REFERENCE TAB
47