Hach LXV525.99A15551, User Manual

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Option Description
Integral Sets the integration part of the PID controller.
The integration part of the controller generates an output signal. The output signal increases
linearly if the control deviation is constant. The integration part responds slower than the
proportional part and can completely compensate disturbances. The higher the integration
part, the slower it responds. If the integration part is set to low, it starts to oscillate.
Derivative Sets the derivative part of the PID controller.
The derivative part of the PID controller generates an output signal which depends on the
control deviation changes. The faster the control deviation changes, the higher the output
signal gets. The derivative part creates an output signal as long as the control deviation
changes. If the control deviation is constant, no signal is created.
The derivative part is able to smoothen the oscillation caused by the proportional part. The
derivative part allows the proportional part to be set higher and the controller responds
faster.
If there is no knowledge about the controlled process behavior, it is recommended to set this
part to “0”, because this part tends to oscillate strongly.
Frequency control function
Option Description
Mode Automatic—The relay output works as a PID controller.
Manual—The relay output frequency has a cycle duration which is set in the MANUAL
OUTPUT menu.
High alarm Sets the maximum cycle duration which can be set by the PID controller.
Low alarm Sets the minimum cycle duration which can be set by the PID controller.
Manual output Indicates the current cycle duration of the output frequency. Additionally the cycle duration
can be set (condition: Mode is set to Manual).
Phase With this menu the leading sign of the control deviation for the PID controller can be
reversed.
Relay setpoint Sets the process value which is controlled by the PID controller.
Dead zone The dead zone is a band around the setpoint. In this band the PID controller does not
change the output frequency. This band is determined as se/- dead zone. The dead
zone stabilizes the PID controlled system which have a tendency to oscillate.
Proportional Sets the proportional part of the PID controller.
The proportional part of the controller generates an output signal which is linearly dependent
to the control deviation. The proportional part reacts on any changes at the input but starts
to oscillate easily if the value is set to high. The proportional part cannot completely
compensate disturbances.
Integral Sets the integration part of the PID controller.
The integration part of the controller generates an output signal. The output signal increases
linearly if the control deviation is constant. The integration part responds slower than the
proportional part and can completely compensate disturbances. The higher the integration
part, the slower it responds. If the integration part is set to low, it starts to oscillate.
Derivative Sets the derivative part of the PID controller.
The derivative part of the PID controller generates an output signal which depends on the
control deviation changes. The faster the control deviation changes, the higher the output
signal gets. The derivative part creates an output signal as long as the control deviation
changes. If the control deviation is constant, no signal is created.
The derivative part is able to smoothen the oscillation caused by the proportional part. The
derivative part allows the proportional part to be set higher and the controller responds
faster.
If there is no knowledge about the controlled process behavior, it is recommended to set this
part to “0”, because this part tends to oscillate strongly.
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