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Table 6: ES+ Multi-Machine Sequencing
5.4 ES+ System Operation
The ES+ sequencing system is a master-less system that rotates the lead and lag compressors
between all of the available machines. The compressors will operate very similarly to Automatic
operation, except that the set points will be controlled by the sequencing network. By varying the set
points across the machines in the network, the load is spread across the network so that the
pressure band is maintained while running only the number of machines required to meet the
demand. Most machines in the network will run fully loaded and modulation will be handled almost
completely by the last compressor in the rotation.
5.4.1 Establishing the Initial Sequence
Once the system has been configured, press the Start button on each of the compressors to start
operation of the sequenced system. Since the sequencing algorithm includes provisions for
automatic replacement of a failed master or 'lead' compressor, it is important for the operator to be
aware of the hierarchy of events when starting the system.
The first compressor placed into sequence mode will become the Lead. However, since any
compressor first placed into sequence has no way of knowing whether a Lead exists, it will first
assume the highest rotation number available. For example, if the number of units to be sequenced
is programmed at four, any compressor will start out in position four when placed in sequence mode.
It will then listen for communications on the bus. If no communication is received, it will assume
position three and again wait for communications. If a compressor with a lower rotation number is
not detected it assumes position two. Subsequently, it assumes position one, which makes it the
Lead compressor.
Before a master is established, the system is not deprived of air. This is due to one of the outstanding
features of the ES+ sequencing system: pressure control is always executed locally at each
compressor. The effective setpoint for compressor control is the programmed setpoint minus 3
*(rotation number - 1). So, while a compressor is counting down towards establishing a master, it
is also capable of delivering air at a pressure determined by the above formula.
To dictate the complete initial sequence manually, wait until the previous machine decrements one
position and then place the next desired compressor in operation by pressing the Start button on
each in sequence. Otherwise, simply press start on all compressors and the initial sequence will be
determined automatically.
ES+ Protocol
Settings
Default Values
Description
*FIXED SPEED MACHINES ONLY*
Number of Units
1
Number of machines in the sequenced group. Maximum 8.
Transfer Interval
24 hours
The Transfer Interval controls how frequently the Lead role is
transferred. A machine will run this many hours before releasing
Leader control and becoming a Lag machine in the sequence.
The next machine in the rotation will automatically assume the
lead role.
Unit Number
1
Number between one and eight assigned to each machine in
sequence. No two machines can share a unit number.
Lag Start Delay
30 seconds
Lag Start delay sets amount of time between a compressor in
the rotation coming online before the next machine in the rotation
will load.
Summary of Contents for Governor
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