Contrec 515 BR03, Operation Manual

Page: 41 / 110

Operation
515 BR03 - 15 August 2021 31
This sequence is used for Loop mode. The tuning procedure is as follows:
1.
Before tuning the control loop it is essential to program in the correct
parameters for the flowmeters, including filtering.
2.
The actual Process Flow Range (P-FLOW RANGE) should be measured
and entered. It is determined by setting the Control Mode to LOCAL,
Batch Mode to RELEASE, setting the
Flow Setpoint
(control output) to
100% (20mA) and then observing the steady state flowrate.
3.
With the correct Process Flow Range entered and Batch Mode still set to
RELEASE the Control Mode should now be set to LOOP to continue the
tuning procedure.
4.
With the Loop Error Deadband (D-BAND) and the Output Ramp Time
(R-TIME) set at zero, the I-TIME should be set to zero (disabled) and the
P-BAND set at 150%.
Gradually decrease the P-BAND value until the system begins to
oscillate when a small step change of the setpoint is introduced. When
this occurs, double the value of the P-BAND.
5.
Next set the I-TIME to 20 seconds and gradually decrease the value until
the system again begins to oscillate when a small step change of the
setpoint is introduced. When this occurs double the value of the I-TIME.
6.
The Deadband and the Output Ramp Time can now be programmed as
required.
The system should be tuned around the flowrate at which the eventual
system will operate. The stability of the loop should then be checked at
various flowrates and setpoints.
Batch Operation Modes
This instrument can operate in the following Batch operation modes:
•
PRESET
•
ON-OFF
•
RELEASE (only available in calibration set mode)
Preset Mode
If the batch mode is PRESET the prestop and shut-off points are
determined by the instrument.
A slow flow start feature is available for smoother batching. The automatic
overrun compensation feature can be used to improve accuracy and
repeatability. An auto-restart feature for automated repeat batches is also
available in preset mode.