310531 37
Configuring the PrecisionFlo Module
Setting PrecisionFlo On and Off Delays
The PrecisionFlo metering valve can physically re-
spond faster than the dispense device and dispense
gun solenoid. As a result, the metering valve can
supply material to the dispense device before the
device has time to open. Supplying material to the
closed device can create a trapped-pressure condition
and cause an excess of material to be dispensed at
the beginning of a cycle.
Similarly, at the end of a cycle, the PrecisionFlo meter-
ing valve can shut off before the dispense device
closes, causing the bead of material to taper off at the
end of a cycle.
To eliminate these problems, you can change the delay
time associated with the opening or closing of the
device and metering valve (Table 4).
Table 4 — Delay On/Off Variables
Variable:
Sets the Amount of Time:
Gun ON
the device delays opening after
regulation begins
Regulation ON
regulation delays starting after
the gun solenoid is activated
Gun OFF
the device delays closing after
regulation ends
Regulation OFF
regulation delays stopping after
the gun solenoid is activated
Fig. 28 and Table 5 show delay ON and OFF timing.
Fig. 28
DISPENSE
Gun Open
PrecisionFlo
Metering Valve
Regulating
A
B
C
D
E
MEASURE
VOLUME
Table 5 — Delay On/Off Timing
A
65 msec
Time between MEASURE VOLUME and DISPENSE
B
Gun ON delay
The user sets either the gun on delay or regulation on delay timing.
The other delay is set to 0
C
Regulation ON delay
The other delay is set to 0.
D
Gun OFF delay
The user sets either the gun off delay or regulation off delay timing.
The other delay is set to 0
E
Regulation OFF
The other delay is set to 0.
To determine which delays to set and what values the
delays should have, follow one of the test procedures
on page 38. If you are using an oscilloscope, follow
Test Procedure A. Otherwise, follow Test Procedure
B to set the PrecisionFlo On and Off delays.
