Graco 234129, Инструкция по эксплуатации

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Jobs
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Jobs
The PrecisionFlo LT system operates using the concept
of jobs. A job is a specified amount of material that is
dispensed by the system. The amount of material speci-
fied for a job varies, depending on the application. In
some applications, a job may be the amount of material
dispensed on a part. Other applications may define a
job to be the amount of material dispensed on a number
of parts or dispensed over a period of time.
A job is initiated when the automation sends a “Dis-
pense Gun” signal to the LT. Once the job is initiated, the
LT will start tracking the amount of volume requested by
the automation and the amount of material that is actu-
ally dispensed. These volumes will be tracked until the
job is completed. At the end of the job, fault calculations
are made and the volumes are stored to non-volatile
memory on the LT system (Job Log).
The LT system watches two things to decide when a job
is complete. Either the “Job Complete” signal is sent by
the automation, or the job complete timer expires. The
type of job end signal is configured in the “Other” screen
to be of type “Timer” or “Digital I/O”. If the timer method
is used, the timer begins counting every time the dis-
pense gun is turned off. If the gun stays off for more than
the preset timer value, then the job is considered com-
plete.
Once the job is complete, the job information is stored to
memory. The most recent jobs can then be viewed on
the “Job” screen or by using the Graco Shell Menu Sys-
tem. The information stored with each job is as follows.
Measured Volume - The amount of material measured
by the flow meter during a job.
Requested Volume - The amount of material that the
automation tries to dispense during a job. This volume is
calculated by measuring how long the dispense gun is
on, taking in effect the command voltage from the auto-
mation over time.
Target Volume - The theoretical amount of material that
a job should have. This value is usually calculated or
found using trial and error when the application is first
set up.
In Bead Mode, all of these volumes are monitored. The
High Volume, Low Volume, and Computed Target faults
are evaluated at the end of the job. The volume alarms
compare the measured volume to the requested volume
and the computed target alarm compares the requested
volume to the target volume.
In Volume Monitor Mode and Batch Mode, the
requested volume is not measured. In these two modes,
the automation command voltage corresponds to a
pressure instead of flow rate. For this reason the
requested volume is not available (as well as the Com-
puted Target fault). The high and low volume alarms
compare the measured volume to the target volume for
Volume Monitor and Batch modes.
In Pressure Mode, there are no flow meters available
and the controls are all performed based on pressure.
For this reason the LT does not monitor measured,
requested, or target volume. The High Volume, Low Vol-
ume, and Computed Target faults are all inactive when
using Pressure mode.