Graco 234129, Инструкция по эксплуатации

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Appendix C
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Appendix C
Theory of Operation
Input and Output Signals
Terminology
For the purpose of this document a digital signal is said
to be SET when voltage is present (or above the mini-
mum threshold). A signal is said to be RESET when the
signal voltage is not present (below minimum threshold).
Devices are referred to as SET when they are in their
energized or active state.
Digital Inputs
Dispense Gun - This is the Dispense Signal. The Preci-
sionFlo LT unit will attempt to dispense at either the
commanded flowrate or commanded pressure while this
signal is SET, dependent on mode.
Control On - This input is reset when the E-stop button
is pressed.
Job Complete - This input can be used to signal a job
end.
The dispenser ready signal is an important signal
for the automation to monitor. When the dispenser ready
output is not on, the LT may not be responding to
requests form the automation. This could create the sit-
uation where the automation is running production, but
the LT is not dispensing any material.
Gun Solenoid - This signal will be set to energize the
gun solenoid at the beginning of a dispense cycle.
Minimum Volume Dispensed - This signal will be set
when the minimum volume (target volume - tolerance)
has been dispensed for the job.
Fault Present - This bit is RESET under the following
conditions:
1. No Faults (alarms or warnings) are active.
In Cycle - In Cycle signal is set at the beginning of a dis-
pense cycle. It is reset at the end of the dispense cycle.
The dispense cycle can end in two ways, depending on
how the Job End mode is set:
• If the Job End mode is set to automation I/O, dis-
pense cycle ends when the job complete signal is
received from the automation I/O.
• If the Job End mode is set to Timer, dispense cycle
ends when the Job End delay timer expires.
Analog Input
Flow Command - The flow command signal input rep-
resents flow or pressure requests. The voltage must be
between 0 and 10 volts DC. The 0-10 volt signal is inter-
preted as a relative 0-100% flow or pressure command
signal. The system must be in Analog Mode for this
input to be used.
Outlet Pressure- The outlet pressure input represents
the fluid pressure at the regulator outlet. The default
voltage ranges from 1 to 5 VDC for 0 to 3500 psi (23.8
MPa, 238 bar).
Analog Output
V/P Command - The V/P command output corresponds
to an air pressure driving the regulator. The voltage
ranges from 1 - 5 VDC to adjust flow and/or pressure in
the fluid system.
Flow Rate - The flow rate output relates to the fluid flow
through the meter. The voltage ranges from 0 - 5 VDC
corresponding to a 0 - 5000 cc/min.