On/Off Delays - Graco PrecisionSwirl Instructions-Parts List Manual

On/Off Delays

The PCF fluid regulator can physically respond faster
than the dispense device and its solenoid. As a result,
the fluid regulator can supply material to the dispense
device before the device has time to open. Supplying
material to a closed device can create trapped-pressure.
At the end of a cycle, the dispense device can shut off
before the pressure has dissipated. This can cause a
dispense of an excess of material at the beginning of the
next cycle.
To eliminate these two problems, change the delay time
associated with the opening of the fluid
regulator/dispense and/or the closing of the dispense
device, see Table 5: On/Off Delay Variables. For
instructions setting on/off delays, see Configure Delay
Settings, page 38.
NOTE: On/Off delay can be set for each dispense
device.
In general, delays should be adjusted so the outlet
pressure during "no flow" is slightly below the outlet
pressure during dispense.
Table 5: On/Off Delay Variables
Variable: Sets the Amount of Time:
Valve ON Sets time from Dispense Valve High
to Valve Open command
Regulator Sets time from Dispense Valve High
ON to Regulator ON
Valve OFF Sets time from Dispense Valve Low
to Valve Close command
Regulator Sets time from Dispense Valve Low
OFF to Regulator OFF
Dispense Valve
Signal
Fluid
Regulator
Valve Open
Command
Valve Actually
Open
F . 32: Timing Delay
IG
3A2098S
A
B
E
F . 32 and Table 6: Delay On/Off Timing show delay
IG
ON and OFF timing.
Table 6: Delay On/Off Timing
A Regulator ON
delay
B Valve ON delay
C Valve OFF Delay
D Regulator OFF
delay
E Valve Open
Reaction Time
F Valve Close
Reaction Time
F
System Setup
The user sets the fluid
regulator ON delay timing.
Usually set to zero. Can be
used to change the starting
point of a bead.
Usually set to zero. Higher
values will lower the trapped
pressure.
The user sets the regulator
OFF delay timing. Zero or
small values will lower the
trapped pressure.
Time delay for valve to
physically open. Delay
varies based on pneumatic
hose length and valve air
volume.
Time delay for valve to
physically close. Delay
varies based on pneumatic
hose length and valve air
volume.
C
D
43