Graco PCF Instructions - Parts Manual page 35

Verify Flow Meter Calibration
Most sealant and adhesive materials are compressible.
Since the flow meter measures the material under high
pressure, the actual volume of material dispensed may
vary slightly from the measured volume, due to this
compressibility. If the K-factor is not correct, the dis-
played volume will not be accurate.
Follow either of the following methods to calibrate the
flow meter during initial setup and on a routine basis to
check for flow meter wear.
Method 1. Using a gram scale
1. Record the flow meter k-factor shown on the Flow-
meter Settings screen (Fluid Plate - screen 4). See
F . 20 on page 28.
IG
2. Use a 500 cc or larger beaker. Measure the mass of
the empty beaker.
3. Manually dispense material into the beaker. Hold
the beaker so that the stream of material is sub-
merged in the captured material to minimize air
entrapment in the container.
4. Record the volume dispensed on the Home screen
1. See F . 25 on page 36.
IG
5. Calculate the actual volume dispensed:
fluid mass (g)
density (g/cc)
6. Calculate the new flow meter K-factor:
displayed volume (cc) x K-Factor (old)
K-Factor (new) =
measured volume (cc)
7. Enter new K-factor.
8. Repeat the procedure to verify the new K-factor.
Method 2. Without using a gram scale, visual measure-
ment
1. Record the flow meter k-factor shown on the Flow-
meter Settings screen (Fluid Plate - screen 4). See
F . 20 on page 28.
IG
2. Use a 500 cc or larger beaker. Measure the mass of
the empty beaker.
313377L
=
measure volume (cc)
3. Manually dispense material into the beaker. Hold
the beaker so that the stream of material is sub-
merged in the captured material to minimize air
entrapment in the container.
4. Record the volume dispensed on the Home screen
1. See F . 25 on page 36.
IG
5. Settle the material into the beaker and view the
actual volume dispensed.
6. Calculate the new flow meter K-factor:
displayed volume (cc) x K-Factor (old)
K-Factor (new) =
dispensed volume (cc)
7. Enter new K-factor.
8. Repeat the procedure to verify the new K-factor.
Manually Adjust Control Loop Parameters
NOTE: It is recommended that these values not be
changed from the factory defaults of 32.00 for Kp,
128.00 for Ki, and 0.00 for Kd.
If the system is not maintaining the desired setpoint
while in pressure or bead control mode, manually
change the Kp and Ki values:
NOTE: Pressure parameters should be adjusted first,
even if you typically operate in bead control mode.
1. Begin dispensing material.
NOTE: Begin a new dispense each time control param-
eters are changed.
2. If the regulator outlet pressure does not closely fol-
low the desired pressure, set Ki to zero then
increase Kp until the proper pressure control is
achieved.
3. If the regulator outlet pressure oscillates rapidly
above and below the commanded pressure,
decrease Kp by 10%. Continue to decrease the Kp
value in 10% increments until the outlet pressure is
stable.
4. Set Ki value to 2 then increase the Ki value until the
system oscillates.
5. Decrease Ki until oscillation stops.
6. Optional: To fine tune the step response in pressure
mode, gradually increase the Kd value.
NOTE: Increasing Kd (pressure only) is typically not
necessary but it may improve step response. However
setting Kd too high may cause the system to oscillate.
7. Stop dispensing.
Operation
35