Alfa Laval PureBallast 135 Compact USCG, System Manual, Page: 97 / 412

3.4.21 Calibrate the control panel’s touch screen sensibility
Follow this instruction to improve the touch precision on the screen, if it is hard
to hit buttons and icons with precision.
Follow the steps below:
1. Pull out the power cable from the 24V DC port on the bottom side of the
control panel. And then reconnect the power cable.
For remote control panels: Use the Power button to turn off, and then turn
on the power.
2. Wait for a sandglass to appear: Press a finger on the screen and hold it
there for approximately 20 seconds.
3. Keep holding the finger on the screen until it turns completely white with a
message “Tap anywhere on the screen within 10 seconds”. Release the
finger and tap once on the screen.
4. Follow the instructions on the screen.
3.4.22 Fine tune flow and pressure control
Calibration of flow and pressure regulation (also called PID calibration) is
performed to fine tune the system so it runs with a steady and even flow and
pressure.
3.4.22.1 Calibrate pressure controlled regulation
During ballast and deballast operation, the control valve is regulated based on
input from the flow transmitter FT201–1 to maintain stable flow. Desired flow is
defined as selected certified flow for the operation minus the Undershoot
percentage set in parameter p111.
During backflush, the control valve is regulated based on input from the
pressure transmitter PT201-72 to maintain stable pressure for efficient
backflush. Desired pressure is defined in parameter p304.
The purpose is to adjust the movement of V201-8 when it changes from flow
controlled regulation to pressure controlled regulation which it does during
backflushing of the filter. The first goal is that the valve travels as fast as
possible to a steady position where it creates required pressure (as defined in
parameter p304).
The second goal is to shorten the time from backflush trigger to start of actual
backflush. This is done by shortening the time in p310 (Backflush initial delay)
that is done after the movement of V201-8 has been calibrated.
Preparations and conditions
• This operation requires login level AlfaLaval.
• All components on page 3.1 Trend shall be selected for plotting, and Flow
FT201–1 shall be used for Y axis selection.
Follow the steps below:
This instruction shall be read together with the example after the instruction.
200000695-1-EN-GB 92
3 Operating instructions and control system description EN