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Safety chain
The safety chain status is connected to the external shutdown input. It is a hardwired circuit consisting of
various safety components, which all need to be healthy, meaning that the chain is unbroken. When this is the
case, the ACP is allowed to run.
Ext. start permission
The external start permission is a digital signal coming from customer equipment to allow the ACP to run. Must
be healthy to allow operation. If not the capacity will be reduced to zero and the compressors will stop.
External alarm
The external alarm may be any kind of external alarm that shall prevent the ACP from running. Must be
healthy (signal high) to allow operation.
PID
Details for the PID regulator status are shown in a separate area [4] on the Control screen. This is relevant
when the operation mode is Auto. For all other operating modes, the setpoint will follow the process value
and the PID output will follow the actual capacity setpoint for smooth transition in case of changing to Auto
regulation.
Compressors
This section shows details about how the capacity is distributed between the available compressors. The
user can influence this somewhat via the start priority. For most applications the start priority should be equal
for all compressors.
Start priority
The compressor start priority can be influenced by the user through buttons [5] on the Control screen. If a
different starting configuration than what the ACP LINK finds optimum is wanted, the user can change the
starting priority number. The number can be set between 1 and 9; the lower the number, the higher the
priority. For optimum regulation handled by the built in algorithms, the priorities for all compressors must be
set equally. A compressor can only start if it is ready to run. That means that a compressor with start priority 2
which is ready to run will start before a compressor with start priority 1, but not ready to run. Setting the
priority to 0 will prevent the compressor from starting and a warning will be issued.
The amount of compressors with a certain status is shown with different values [6]. This section also shows
the minimum capacity requirement to start the ACP:
# Compr.Enabled: Shows how many compressors are enabled or available on the ACP.
# Compr.Ready: Shows how many compressors are ready to be used for operation and delivering the
requested capacity.
# Compr.Starting: Shows how many compressors are currently in the starting phase (start timer active).
# Compr.Running: Shows the amount of compressors currently running.
Min Cap. To start: Shows the minimum necessary request to start the unit. This is equal to four thirds of the
lowest available minimum compressor capacity.
10.4
Compressor screen (Compr.)
This screen shows status and key parameters of the compressor. There is a screen for each compressor. The
“Alarm Status” shows alarms and warnings as transferred from the compressor CM-SW-01 module. These
alarms are also shown in the HMI’s alarm- and warning screens in citation marks. The motor current, set point
and actual capacity based on slide valve position and motor speed are shown in detail.
