designing a small section of a communications
network in an abattoir two-stage ammonia refrigeration system
all hardware is to be selected
from the AS-I range manufactured by Pepperl and Fuchs, information available at
[login to view URL] .
The section of the plant that you will be controlling includes 4 package plant ammonia
compressors, their associated valving and the fan banks on the evaporator and
Each compressor has a small PLC performing local control and providing a number of
inputs and outputs (I/O) to the larger plant PLC that coordinates the overall plant
operation. The compressor PLCs are located in a small control cabinet mounted on
the compressor pad.
The valves are field mounted on the ammonia piping to and from the compressors and
are controlled by the plant PLC.
The network is to be an AS-Interface network, connected to a Pepperl and Fuchs ASInterface
master VBM-CLX-DM in a ControlLogix rack on the main PLC. The details
of the rest of the control system are not relevant to your task, you just need to ensure
connectivity between the devices and the AS-I master.
There is an Emergency Stop button located on each compressor control panel and the
main control cabinet that must be linked using safety I/O back to a Safety Monitor that
is located in the main PLC cabinet. The design of the safety system in out of the scope
of this project and will be completed by an RPEQ.