Super Systems 9205 Series - Manual (Page 117)

Series 9205 Operations Manual Rev A 116
Alternate PID Setup
IMPORTANT!
PID Auto Switching must be enabled in the PID Loop Setup menu before Alternate PID Setup settings will
be applied. This applies only to the Loop 1 – Loop 3 Set1-Set 3 menu options. All other menu options are for
recipe Opcode PID control.
The Alternate PID Setup menu option allows for
up to 16 sets of PID values to be used on all two
loops via the programmer. This menu option is
frequently used if a different PID would be more
suitable once a furnace reaches a certain
temperature, oftentimes in vacuum applications.
There is a choice of PID 1 – 16, and LP1 Set 1 -3,
LP2 Set 1 – 3, and LP3 Set 1 – 3.
Prop Band (0 for On/Off)
Proportional Band determines the response to the current error. The Proportional Band is the percent of
the range of the process variable that will produce 100% output and is the inverse of the proportional gain.
A low Proportional Band value results in a larger change in output for a given error. Conversely, a high
Proportional Band value results in a smaller change in output for a given error. If the Proportional Band is
too small, control may oscillate or be otherwise unstable. If the Proportional Band is too large the control
action may be too sluggish in response to changes within the system. Note: If the Proportional Band is set
to 0.0, only on/off control is performed. The range of values is –1.0 to 999.0.
Reset
Reset determines the influence of past errors. The Reset, or integral action (expressed in repeats per
minute), sums the error between the process variable and setpoint over time and adds this accumulated
output to the proportional output. A “proportional only” controller generally operates with steady-state
error because some error is required to produce control output. The goal of integral action is to drive the
steady-state error to zero and eliminate this droop. The range is 0.00 through 10.00.
Rate
Rate adjusts the response to future errors. The Rate, or derivative action (expressed in minutes), is used to
predict system behavior and has a dampening effect. The more the controller tries to change the process
variable the harder the derivative will work to counter that effort. This dampening effect can be valuable in
reducing overshoot but is most often useful when trying to improve control on systems with significant and
predicable lag. The range is 0.00 through 10.00.
Integral Preset
This is the integral preset value. This field provides an offset for the starting point for PID control, also
referred to as “Load Line” or “Manual Reset”. The range is –100 to 100.
High Limit
This is the high limit value. The range is –100 to 100.
Low Limit
This is the low limit value. The range is –100 to 100.