VAT 653 Series - Control Parameters

Series 65 INSTALLATION
963283EA Edition 2019-05-03 53/
129
4.10.2 Control parameters
This chapter describes the functionality of Controller 1 to Controller 4.
4.10.2.1 Control algorithm
Parameter location:
CPA RS232
Pressure Control
Pressure Control->Pressure Controller 1
Pressure Control->Pressure Controller 2
Pressure Control->Pressure Controller 3
Pressure Control->Pressure Controller 4
See command list - s:02
The main parameter of a controller unit is its Control Algorithm. There are different control algorithms
implemented in the firmware of the valve. The user can select the control algorithm which fits his
demands.
Control Alg
orithm
Description
Adaptive
This is the most dynamic control algorithm. Before using adaptive control
algorithm, a special procedure called “learn” must be executed first (see
chapter x). The valve will observe the behavior of the vacuum system by
moving the valve to different positions. During the learn procedure the
valve performs an internal parameter estimation correspondent to the
vacuum system.
Note: The adaptive pressure control work at its best if the conditions
(mainly gas flow) are close the conditions at the learn procedure.
PI
This is a solid algorithm for pressure control. The performance will be
behind the adaptive control algorithm. But if the condition varies a lot, it’s
possible that the adaptive control algorithm does not work properly so the
PI algorithm provides the best result.
Soft Pump
Is a modified PI control algorithm to pump down from atmospheric
pressure. This control algorithm has been optimized to prevent that the
pressure in the chamber is falling too fast (reduce occurrence of
undershoots).