Graco 3A2098H Automation Control Normal Operation, Jobs in Bead Mode, Jobs in Pressure Mode

Automation Control (Normal Operation)

During automation control (normal operation), the sys- tem can dispense or change dispense parameters when it receives a command from the automation unit.

The automation control operates using the concept of jobs and styles. For a detailed explanation of jobs and how they work within the PCF system, see Jobs on page 45. For a detailed explanation of styles and how they work within the PCF system, see Styles on page 46.

Jobs

NOTE: See Appendix D - I/O Signal Descriptions, page 138, for automation input and output signal descriptions.

A job is an automation sequence in which material can be dispensed. The amount of material specified for a job varies by application. In some applications, a job may be the amount of material dispensed on a part. Other appli- cations 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 Style Strobe signal to the PCF. Once the job is initiated, the PCF will start tracking the amount of volume requested by the automation and the amount of material that is actually dispensed. These volumes will be tracked until the job is completed. At the end of the job, error calcula- tions are made and the volumes are stored on the PCF system (Job Log).

The PCF system monitors two things to determine when a job is complete. Either the Dispense Complete signal is sent by the automation or the job complete timer expires. The type of job end signal is configured to Timer or Gateway in Fluid Plate x, screen 1 (Control Settings). If the timer method is used, the timer begins counting every time the dispense valve is turned off. If the valve stays off for more than the preset timer value, the job is considered complete.

Once the job is complete, the job information is stored to memory. The most recent jobs can be viewed on the Job screen. The information stored with each job is as follows. See Job Report Screens, page 114, for instructions on how to view job reports.

Operation

Actual (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. In Bead mode, the requested volume is calculated as the requested flow rate multiplied by the duration of the dis- pense. In all other modes, the requested volume is same as the target volume.

Target Volume - The amount of material a job should have. This is defined in the Style.

Jobs in Bead Mode

In Bead Mode, all of the previously mentioned volumes are monitored. The High Volume, Low Volume, and Computed Target errors 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.

Jobs in Pressure Mode

In Pressure Mode, the requested volume is not mea- sured. In this mode, 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 Computed Target error). The high and low volume alarms compare the measured volume to the target vol- ume for pressure mode.

Continuously Running Applications

In some cases the target volume for a job is not known. An example of a case where the target volume is unknown is a continuously running system. This would be a system that does not run jobs, but runs continu- ously over a day or a shift. In this case, the flow rate becomes more important than the amount of volume dispensed in a job. The way to handle this situation is to set the target volume to a value of zero. This effectively disables the Computed Target error. The controls will still maintain the desired flow rate and report errors cor- responding to the tolerance set for the running style.

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