Graco 234129, Инструкция по эксплуатации

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Frequently Asked Questions
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Frequently Asked Questions
Q:
What is the difference between running in Volume Monitor versus Bead Control?
A:
In Volume Monitor the control will maintain a specific pressure at the fluid regulator outlet. If the viscosity of the
fluid changes or the nozzle becomes restricted, that pressure will result in a different flow rate. If you have a flow
meter installed it can still monitor the job volume for faults. Volume monitor is sometimes desirable for spray
applications to maintain a specific spray pattern.
In Bead Control the fluid regulator is still reacting to the fluid pressure for quick adjustment, but the control also
monitors the flow meter. If the flow rate does not agree with the flow command, the pressure target is adjusted.
This method gives you the quick response of a pressure transducer, while maintaining the rate accuracy of a
flow meter.
Q:
How do I adjust the flow rate up or down without changing my automation commands?
A:
There is an adjustment called Bead Scale which appears on the EasyKey Run screen or on the Dispense Setup
Screen. This can be set from 50-150% of command flow. To change the Bead Scale turn the key switch to the
right to enter Setup mode. The Setup mode screen allows you to change the Bead Scale percentage. To change
to the new setting press the Enter key on the EasyKey interface. The new value will be stored when you turn the
key switch back to Run mode. In Run mode the Bead Scale can be changed using the bead adjust keys.
Q:
Why do I get a warning for “Volume Compensation Limit”?
A:
Something has changed since you calibrated the regulator. The control has changed the regulator pressure set
point too far away from the calibration point. This happens in Bead Control when the control is monitoring the
flow meter and trying to maintain the proper flow rate. The cause is some factor that has changed the pressure,
downstream of the regulator, at the desired flow rate. This might be a plugged nozzle or a fluid viscosity change.
The viscosity difference could be caused by a change in temperature or a new batch of material. If the pressure
needs to increase to maintain the desired flow rate, but the fluid regulator is already fully open, the volume com-
pensation continues to increase the desired pressure target until the limit is reached. The fluid feed pressure at
the regulator inlet needs to be increased. If the fluid and equipment are all right you need to recalibrate to your
flow target.
Q:
How is a fluid control regulator calibration performed?
A:
There are three steps: (1) determine system maximums (2) pressure calibration (3) flow calibration. These steps
are performed sequentially during the calibration process. If you are not using a flow meter and will run in pres-
sure control mode, only the pressure calibration and system maximums will be performed. To calibrate pressure
and flow, see page 104.
Q:
How do I know if the fluid control regulator calibration was successful?
A:
On the EasyKey display, calibration was successful if the calibrate setup screen indicates “Calibration Valid”.
Q:
Why will my fluid control regulator not calibrate in the calibration screen?
A:
You may not have enough fluid pressure downstream of the regulator. Raising the downstream pressure
becomes more important if the pressure is below 500 psi (3.5 MPa, 34.5 bar). Try a smaller nozzle on the dis-
pense valve.