Pulse Instruments EP2100, Инструкция по эксплуатации

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Parameter Description Units
K
p
Gain unitless
T
i
Integral Time seconds or seconds/repeat
T
d
Derivative Time seconds
Output (%) = K
p
e(t) +
f
e(t)dt + T
d
de(t)
dt
1
T
i
Parameter Description Units
e(t) Current Error % of full scale
dt Delta Time Between Readings seconds
de(t) Difference Between Current Error & Previous Error % of full scale
Parallel
The parallel form allows the user to enter all parameters as Gains. In all cases, larger gain values result in faster
output response.
Parameter Description Units
K
p
Proportional Gain unitless
K
i
Integral Gain 1/seconds
K
d
Derivative Gain seconds
Output (%) = K
p
e(t) + K
i
f
e(t)dt + K
d
de(t)
dt
Integral Value Management
To determine the integral component of the PID calculation, the controller software must maintain a running total
of the accumulated area under the error curve (Current Integral). The sign of the value added to the accumulated
Current Integral during each cycle may be positive or negative based on the current Direction setting as well as the
relative values of the current process reading and the set point.
Override Control
The Current Integral accumulates when the output is set to Auto mode. If the controller is switched to Off mode,
the value no longer accumulates, but it is not cleared. Therefore, PID control will resume where it left off if the
controller is switched from Off back to Auto. Similarly, accumulation of the Control Integral will be suspended if
the output is interlocked and resume after the lock-out is removed.
Bumpless Transfer
When the output is switched from Hand to Auto mode, the controller calculates a value for the Current Integral
using the current error to generate the same output percent as the Hand Output setting. This calculation does not
use the Derivative tuning setting to minimize errors from momentary fluctuations in the input signal. This feature
ensures a smooth transition from manual to automatic control with minimal overshoot or undershoot as long as the
user sets the Hand Output percentage close to the value that the process is expected to require for optimal control
in Auto mode.
Wind-up Suppression
The Current Integral value that is accumulating while the output is set to Auto can become very large or very small
if the process value remains on the same side of the set point for a prolonged period of time. However, the control-
ler may not be able to continue to respond if its output is already set to the minimum or maximum limits (0-100%