Graco 332564B important safety instructions Flow Control System

Page 57

Operation Using a Programmable Logic Controller (PLC)

Flow Control System

Overview

Flow control is an optional feature that precisely regulates the flow of material to an automatic spay device, to help ensure adequate coverage and avoid sags or runs in the finish coat. The ProMix PD2K system can control fluid flow by directly controlling the proportioning pumps. The pumps accurately dispense a fixed volume of fluid during each stroke. For this reason, the flow rate of a given pump is directly proportional to the velocity of the pump. As long as the gun is open and the system is stable, flow control is the most effective method for controlling flow rate.

The flow control system relies on two main inputs for controlling flow rate: Gun Trigger and Control Set Point. NOTE: These inputs are timing critical. Graco recommends that users wire them discretely to the controller. Alternatively these two inputs can be driven by the network communications, but latency could be an issue for systems requiring precise timing.

See System Screen 5, page 71, for more details on configuring these options for ‘Discrete’ or ‘Network’.

NOTE: Flow control cannot be selected with a manual gun system.

Normal Flow Control

The ProMix PD2K will directly control the speed of the pump(s) to the programmed flow control set point to maintain accurate flow rate and ratio. The flow control set point is set by Network Communications or the Discrete Input.

The system is considered to be stable when the pressure readings do not fluctuate and the flow rate is maintained. While the system is considered stable it will store (“learn”) the associated pump pressures to a table that is used if the gun trigger signal is lost or removed.

Pressure Control

When the gun trigger signal is removed the system automatically switches to pressure control mode to avoid over pressurizing the fluid lines and to allow smooth transition to flow control if the gun trigger signal returns. It also works to maintain a consistent flow rate even though it has transitioned to pressure control mode if the gun trigger signal is inadvertently lost.

Gun On/Off Prediction

The pressure table also is used to predict if the gun has been turned on or off (without a change to the gun trigger input). The flow control system continually monitors the desired outlet pressure compared to the actual outlet pressure. If the actual pressure remains 50% higher than the desired pressure for longer than 10msec, then the system predicts that the gun trigger has been released. If the actual pressure drops below the desired pressure longer than 10msec, then the system predicts that the gun has been triggered.

The gun on/off prediction is used in the flow control algorithm to prevent the fluid pressure from becoming too high or too low due to a system disturbance. For example, if a gun off prediction occurs while the gun trigger input is high, the system will begin to control to the pressure value last stored in the pressure table for the current flow set point.

System Startup and Defaults

The pressure table is stored in volatile memory, so the table values will be lost after a power cycle of the ProMix PD2K controller. This issue is not significant because the system generally is able to recalculate new pressure table values within a few seconds (depending on the stability of the fluid system).

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Contents
ProMix PD2K Proportioner for Automatic Spray Applications Important Safety InstructionsContents Related Manuals Manual No DescriptionManual No Models ECB Labels0359 Model AC2000 High Pressure Identification Label Fire and Explosion Hazard Intrinsic Safety Personal Protective Equipment Isocyanate Conditions Important Isocyanate ISO InformationKeep Components a and B Separate Moisture Sensitivity of IsocyanatesGeneral Information USB Download Procedure Advanced Display Module ADMADM Display USB Upload Procedure ADM Keys and Indicators Function ADM Keys and IndicatorsSoft Key Icons Soft Key FunctionsKey Function Key Function Screen Icons Navigating the ScreensPre-operation Checklist Power OnPre-Operation Tasks Initial System Setup Flush Before Using EquipmentValve Settings With Color Change Without Color ChangePrime and Fill the System Operation Using Automatic Display Module ADMSpraying Flush Mixed Material PurgingFlush the System ShutdownSingle Color System Color Change SystemNetwork Communications and Discrete I/O Operation Using a Programmable Logic Controller PLCDiscrete I/O PD2K Discrete I/O ConnectionsAnalog Inputs Digital InputsKEY Discrete I/O Connections on EfcmCommunication Gateway Module CGM Details CGM OverviewCGM Kits Number Operation Mode Description Output Register 00 Current System ModeNetwork Communication I/O Data Map ProMix PD2K Network OutputsPump States for Output Registers Description Ber Output Registers 01, 02, 03, and 04 Pump StatusOutput Register 05 Actual Mix Flow Output Register 06 Actual Mix RatioOutput Register 27 Safety Interlock Input Status Output Register 14 Active Recipe Potlife Timeout Set PointOutput Registers 28 36 DCS Command Structure Output Register 12 Active Recipe Material B Flush SequenceOutput Register 38 40 Software Version Output Register 37 TimeOperation Using a Programmable Logic Controller PLC None Network Output Data Map Read OnlyPSI = ACK = Busy= NAK = ERRProMix PD2K Network Inputs Input Register 00 System Mode CommandInput Register 02 Flush/Prime Pump Command Input Register 03 Mix Pump 1 Control Set PointInput Register 07 Go to Recipe Number Input Registers 14 21 DCS Command Structure Input Register 08 Clear Active AlarmInput Register 09 Job Complete Input Register 10 Gun 1 TriggerOperation Using a Programmable Logic Controller PLC Network Input Data Map Write/Read 40180 Gun 3 Trigger Uint32 Purge Mode Sequence Operation Flow ChartsInactive Pump Flush and Prime Sequences Flush Pump CommandChange Color Change SequenceStandby Mix Ready? no Mixing SequenceClear Active Alarm Alarm Clearing SequenceDynamic Command Description Network Communication Dynamic Command Structure DCSDynamic Commands with Command ID List of DCS CommandsWrite User ID DCSWrite Recipe Write Flush Sequence Read User ID Write Fluid Control ModeRead Flush Sequence Read RecipeRead Fluid Control Mode Yymmdd Read Job InfoRead Alarm Info YymmdddwExample Ascii Character String Decode Algorithm Read Event Info Flow Control System Run Mode Screens Opening ScreenHome Screen See Advanced Screen 1, page 82, to set Home Screen Key Description DetailsKey Description Key Description Spray Screen Spray Screen, in Standby ModeFill Screen, Color a Selected Fill ScreenUsage Screen Usage ScreenErrors Screen Jobs ScreenEvents Screen Password Screen Setup Mode ScreensSystem Screen Mix No Flow Timeout Mix Idle TimeoutLow Flow Timeout Mix Pressure ToleranceGun Hose Diameter Gun Hose LengthMix At Wall Hose Length and DiameterGateway ID EnableFlow Control Setpoint Signal Gun Trigger SignalFluid Control Manual OverrideRecipe Screen Flush Screen Pump Screen Default Settings Not Selected Default Settings SelectedPump Screen 3, Pressure Monitoring Disabled Pressure Alarm and Deviation LimitsCalibrate Screen Calibration ScreensVolume Check Screen Enter Measured Volume of Solvent Maintenance Screen Maintenance ScreensMaintenance Screen 4, Color Valve Resets Advanced Screen Log 90% Full Advisory Enabled Enable USB Downloads/UploadsDisplay Units Download DepthCalibration Checks Pump Pressure CheckPerform the pressure check Pump Volume Check Scroll to Calibrate Screen 3, Solvent Meter CalibrationColor Change Single Color SystemsMultiple Color Systems System Errors To Clear Error and RestartGun Trigger Input Function Error Codes Purge Errors Code Type Description Problem Cause SolutionMix Errors Code Type Description Problem Cause Solution Pumping Errors Code Type Description Problem Cause Solution EBH# Code Type Description Problem Cause SolutionSAD1 Pressure Errors Code Type Description Problem Cause Solution Qbdx QadxEmix System Errors Code Type Description Problem Cause SolutionCA0X CAC#Cagx CDC#Cddx USB Errors Code Type Description Problem Cause Solution Wxud USBWxuu B9AX B9BXB9SX END# Calibration Errors Code Type Name DescriptionENS0 ENT#Code Type Name Description Maintenance ErrorsPreventive Maintenance Schedule MaintenanceCleaning the ADM FlushingPositive Displacement Metric Proportioner Technical DataGraco Standard Warranty Graco InformationFor Graco Canada Customers
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