Curtis Dyna-Fog 2742, Manual

Page: 49 / 84

SPEED DECODE MODULE
The speed decode module is included in all machines equipped with the
SYNCROFLOW option.
This module is similar to the tachometer decode module in that it uses a frequency
to voltage to converter and an external sensor to generate a pulse rate. The speed
decode module is driven by a Hall effect sensor which is mechanically coupled to
the transmission of the vehicle. The sensor contains a 20 pole monolithic magnetic
device which rotates at the rate of 1000 revolutions per mile, thus generating a
pulse rate of 20,000 pulses per mile. At 20 miles per hour, this corresponds to
400,000 pulses per hour or 111 pulses per second.
The frequency to voltage converter is calibrated for 6.6 volts output for 111 pulses
per second input (6.60 volts at 20 mph). An attenuator of 331:1 in the remote control
box causes the meter to read 20.0 mV at 20 mph. In the syncroflow mode this
voltage is used as the command voltage in lieu of the fixed voltage in the manual
mode.
The connections to the module are as follows:
PIN FUNCTION DESCRIPTION
1 Ground to sensor Provides a ground reference to the Hall effect speed
sensor.
2 Not used
3 Ground input Input ground from system.
+5 VDC INPUT
OVERRANGE
SPEED OUT
SENSOR INPUT
NOT USED
+ 10 VDC TO SENSOR
+ 10 VDC IN
NOT USED
GROUND INPUT
GROUND TO SENSOR
REFERENCE TAB
49