2 tuning a fast delivery system, Section 3.2.1.2, tuning a fast delivery – INFICON Composer Gas Concentration Controller User Manual

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Composer Operating Manual

Figure 3-9 Examples of Delay, or Deadtime Settings

3.2.1.2 Tuning a Fast Delivery System

If the source response has been characterized as fast (Dead Time is less than
1 second), set the INTEGRATING TYPE control parameters as follows:

DEAD TIME . . . . . . . . . . . . . . . . . since this is a fast source, set this

parameter’s value to 0.1 and leave it there.

TIME CONSTANT. . . . . . . . . . . . . set this parameter’s value to 0.1 and leave

it there.

PROCESS GAIN . . . . . . . . . . . . . approximate the process gain by dividing

the increase in concentration (%) by the
increase in Bubbler flow rate (sccm). Set
this parameter to this computed value.
Optimize this value by changing the value
in use. Remember that increasing the
value of this parameter reduces the
controller change for a given error in the
measured concentration. That is, the
system responds more slowly with higher
values of process gain.

NOTE: If satisfactory control cannot be established using only PROCESS

GAIN the system is probably not a fast system.