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User
Guide RS8KH202 © Danfoss 2019-03
AK-PC
572
Introduction
Application
The controller is used for capacity regulation of compressors
and gas cooler in small CO2 refrigeration applications.
Advantages
• Energy savings via:
- Optimal control of CO2
- Optimisation of suction pressure
- Night time increase
- Floating gas cooler reference
- Heat recovery
- Load limitation
• Simplified setting of the functions
The controller ensures that the different control settings are
adjusted in accordance with one another. Only basic settings are
required.
• Ongoing adjustment of control references
Newly developed algorithms adjust the problematic pressure
ratios in the CO2 controller.
Input and output
There are a limited number of available inputs and outputs so
most connections are intended for one specific function.
However, there a few options for AUX use:
• If only one or two compressor units are connected to the MT
circuit, there will be a DI input available. This could, for example,
be used as an alarm input.
• If the compressor used is not a Bitzer CRII, a solid state output
can be used for oil management.
• If heat recovery is not used, the AUX3 function can be used for an
alarm function.
In order to control the high pressure valve and receiver pressure
valve, two valve driver modules, type EXD 316, must be con-
nected.
The overview of connections can be seen on page 22.
Operation
The daily operation can be set up directly on the controller or
via an external display device.
During set-up, the display images will be adjusted so that only
the relevant images are opened for additional setting and
end-user operation.
The operation is password protected, and three levels of
access can be granted.
The controller contains several languages. Select the preferred
language at start-up.
Data communication
The controller has built-in modbus data communication, and it
can be connected to an AK-SM 800 type system device.
As a minimum, control of a condensing unit can be performed
using one compressor unit, one gas cooler and one receiver.
A maximum of 3+2 compressors can be regulated.
Fx:
