Bitzer ACP Link, Техническая информация

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CT-600-2 53
Motor error signal inversion (Comp./Motor \ Page 2)
Parameter to invert the error signal from the drive/motor. The default setting expects that a low signal means
an error exists. It is possible to switch to the alternative where a low signal means that the drive/motor is
healthy.
Oil temperature high and low warning and alarm limits (Oil System \ Page 2)
Parameters to adjust the limits for surveillance of the oil temperature.
PID regulator parameters (PID \ Page 1)
Set the type of regulator that is used when the regulation mode is auto. Also set the setpoint for the regulator
and the minimum capacity for start of compressor.
The parameter “min capacity output before start-up” is only effective if its value is higher than the minimum
capacity request for starting the first compressor. This minimum request value depends on the configuration
of the available compressors. Its value is shown on the CTRL page.
The PID regulator is a function to minimize the error between a setpoint and a process value, by manipulating
the capacity setpoint to the ACP. The following equation shows the PID output:
𝑦 𝑡 𝐾𝑃 𝑒 𝑡
1
𝑇𝑁
𝑒 𝑡 𝑑𝑡
𝑇𝑉
1 𝑇𝐷
𝑑𝑒 𝑡
𝑑𝑡
Where:
y(t) = PID output
KP = Proportional gain
TN = Integral time
TV = Derivative time
TD = Filter time for derivation
e(t) = Process error between setpoint and feedback value (process value)
The PID regulator has different features:
 Parameters for Proportional (KP), Integral (TN) and Derivative (TV) action can be set individually.
 Operates in so-called manual-mode when PID regulator is not used (all operation modes other than
“Auto”).
 Anti-reset windup to avoid saturation or wind-up in integral action (PID inner window I-part and PID outer
window I part).
 Damping time (TD) to filter the overshoot due to derivative action.
 Bump less transfer to avoid sudden change in PID output, when the mode changes.
 Warning issued, when PID function has error state.
PID regulator tuning parameters (PID \ Page 2)
There is a sub section on the second PID page for tuning each of the four regulator types. Tuning parameters
for each regulator can be found by toggling the arrow buttons called “Reg. Type” at the bottom of the page.
The PID regulation is intended to control operation around the nominal operating point and shall be tuned
during normal and stable operation of the plant. Transient conditions, such as start-up or a sudden drop in
cooling requirement are not expected to be handled by the PID regulator. The ramp function, to control the
start-up is described further below. The capacity limiter function (see also section 5.3) can be used to force
quick reduction of capacity, triggered by different warnings, such as low suction pressure, high pressure ratio
or low process temperature. Detailed information about how the PID regulation operates and how to tune it, is
out of scope of this document.
PID KP Parameter to tune the proportional gain of the PID regulator.
PID TN Parameter to tune the integration time of the PID regulator.
PID TV Parameter to tune the differential time of the PID regulator.