13–10–613 SP Page 28
Program all members of the system, as described in
the programming procedure on previous pages. All ad-
justments should be identical for each member, except
for unit number. The sequencing system will make any
necessary adjustments to the setpoints to properly run
the compressed air system.
Operation – Press the SEQUENCE key on each of the
compressors to start operation of the sequenced sys-
tem. Once this is done, the member controllers will op-
erate the compressor units as required to maintain the
plant pressure between the programmed Set and Re-
set Pressures, for demands from 0 CFM up to the ca-
pacity of the system.
While operating, each controller will display a se-
quence number. As demand requires, the units will
start and load in order, starting with sequence number
1 (lead unit). As demand falls, the higher sequence
number units (lag units) will modulate, unload, and
stop.
If any member of the system is taken out of sequence
mode for any reason, other units with higher sequence
numbers will automatically promote as required. Se-
quence numbers will start with 1, and will be assigned
on other units up to the number of compressors in the
system. This feature makes the system completely tol-
erant of any manual or protective stopping of any mem-
ber.
ESTABLISHING THE INITIAL SEQUENCE
The first member compressor placed into sequence
mode will become the lead unit. However, since any
controller first placed into sequence has no way of
knowing whether or not other members already exist,
it will first assume the highest rotation number avail-
able. For example if the number of units to be se-
quenced is programmed at four, any compressor will
start out in position four when placed in sequence
mode. It will then listen for other units on the commu-
nications line.
If there is no member with the next lower sequence
number, the controller will automatically promote itself.
This movement is fairly rapid with the ES+ controller,
and the number will advance to the lowest vacant posi-
tion in several seconds.
To establish a desired order of units, press STOP/RE-
SET or select any mode other than sequence (if al-
ready in sequence, put into auto mode if you wish to
continue operation while doing this selection). Then
put the desired lead unit back into sequence. Wait until
it promotes one step (or longer), then put the desired
#2 unit into sequence mode and wait until it promotes
one step, and so forth until all units are back into the se-
quence mode.
During this procedure, the system is not deprived of air.
This is due to one of the outstanding features of the
“AUTO SENTRY–ES+” sequencing system: control is
always executed locally by each member controller. So
while a controller (or controllers) is/are counting down
towards the final order, they are also capable operating
their compressor and will deliver air. Once the se-
quence order is finally established, setpoints will con-
tinue to be adjusted in each member to provide opera-
tion in the preferred order. This may take several
minutes after a manual change of sequence numbers.
ES+ SEQUENCE SYSTEM OPERATION
Each member compressor in the system operates sim-
ilarly to the Automatic mode of operation. It will start,
load, modulate, unload, blowdown, and automatically
stop as necessary to meet system demand for air.
There are several differences, however, when running
in the Sequence mode.
The pressure shown on the top line of the display is the
average system pressure of all the members. Each
member communicates its local pressure through the
communications cable, for use by others in the system
for display and control. The system responds to this
average. This number will be the same for all units in
the system. To obtain the local package discharge
pressure, select the “SYS PRESS” alternate display on
the lower line.
Pressure setpoints are continuously adjusted, depend-
ing on the operation of the members. The last lag unit
which is loaded will control its modulation to keep the
system pressure near the programmed Set Pressure,
and serves as the trim machine. Any running lead unit
will be adjusted for slightly higher pressures, and will
run at or near capacity. The first unloaded lag unit will
have its reset pressure adjusted so it will come on line
if the system pressure drops to the programmed Reset
Pressure. The system is continuously adjusted to
maintain the system pressure between the pro-
grammed Set and Reset Pressures.
If any lag unit is loaded, any preceding lead unit will be
loaded. Its blowdown timer will reset and hold at full val-
ue. This ensures that the last lag unit will always be the
first to unload and blow down, and lead units will be pre-
pared to handle the demand.
When demand exceeds the capacity of the loaded lead
compressor(s), the pressure will drop. If a lag unit is
stopped, its restart will be delayed. This delay is the ad-
justable “Lag Start Delay”. This allows time for lead
units and stored air to serve intermittent demands,
without starting another compressor. The next avail-
able member accumulates any time spent below Reset
Pressure, and will start whether there are repeated
brief demands or a sustained demand. The Lag Start
Delay timer does not begin timing until the preceding
member of the system is loaded.
Summary of Contents for ELECTRA-SAVER EAYQ E
Page 15: ...13 10 613 SP Page 6 DECALS 206EAQ077 212EAQ077 218EAQ077 211EAQ077 207EAQ077 ...
Page 16: ...13 10 613 SP Page 7 DECALS 216EAQ077 217EAQ077 222EAQ077 221EAQ077 208EAQ077 ...
Page 31: ...13 10 613 SP Page 22 FIGURE 4 2 FLOW CHART FOR SET UP PROGRAMMING ...
Page 48: ...13 10 613 SP Page 39 FIGURE 4 13 WIRING DIAGRAM 202EAY546 Ref Drawing ...
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