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13–10–613 SP Page 29
SEQUENCED SYSTEM CHECKOUT
One of the best indicators of the stability of the system
is to compare the local system pressure of a running
unit with the system average pressure. To do this, sim-
ply press the [<] or [>] cursor keys until the lower line
of the display shows SYS PRES and the local pressure.
In a properly operating system, this value will be within
1–2 psi of the top line value, and will change slowly as
demand and delivery are changing. Rapid and large
changes in local pressure indicate system problems.
Ensure that all compressor units are piped to a com-
mon system pressure with adequate storage to handle
the plant demands. Select other operating modes if
rapid response to large demand changes is needed.
The system is redundant, and will tolerate any break-
down in communications. If any unit is taken out of the
Sequence mode, other members will “fill the gap” to
keep the system operating. If a break should occur in
the communications cable, the compressors will con-
tinue to function as two systems, one on each side of
the break. Each will have its own lead unit (Seq 1) and
may have lag units (depending on how many ES+ con-
trollers are on that side of the break). Look for a cable
break if there are multiple units with the same Se-
quence number displayed.
Each ES+ controller also monitors the communications
data for errors. If these occur, the yellow advisory will
come on, and the controller displays a message to
check the communications port. If this message
comes on, and one member changes to “AUTO” opera-
tion, then it has been mistakenly programmed with the
same Unit Number as another member. Refer to pro-
gramming instructions above for instructions on pro-
gramming.
Automatic Rotation – After the lead compressor has
served for the duration programmed (TRANSFER IN-
TERVAL), it relinquishes control and assigns itself the
highest available rotation number. The lag compres-
sors detect the loss of the lead unit and decrement their
rotation numbers. Number 2 becomes number 1, the
new lead unit, number 3 becomes number 2, etc. The
former lead unit will become the last lag unit.
The transfer interval timer operates whenever a mem-
ber is the lead (Seq 1) unit of the system. It will continue
to time out regardless of other units in the system. The
remaining time is retained during power interruptions.
It is reset back to full value if the controller is in any
mode other than Seq 1.
Other Sequencing Features – Any air system will ex-
hibit pressure differences from one point to the next.
Even a well designed multi–compressor installation will
show ’minor’ pressure variations between one com-
pressor’s discharge point and another compressor’s
discharge. These points will also vary from the actual
system storage (normally the air storage receiver).
The “AUTO SENTRY–ES+” sequencing system is de-
signed to tolerate minor variations. The “AUTO
SENTRY–ES+” sequencing system will automatically
adjust the system setpoint to maintain the average sys-
tem pressure. Overpressures within any member com-
pressor are prevented locally, and other members will
load up to meet the demand. When a turn valve com-
pressor is provided with current monitoring, the control-
ler will also shed some load on any overloaded unit, and
lag units will load as required to service the demand.
The dynamic setpoint control is completely automatic
and is continuously adjusted.
If airflow is restricted between the compressor units
and the common storage, the ’minor’ variations de-
scribed above become more significant. The pressure
in the receiver will always be lower than that sensed by
the compressor system. The ES+ system will tolerate
this, and will still maintain the average pressure within
limits. These restrictions will spread modulation over
several units, rather than showing the strong prefer-
ence to unload the last loaded lag unit.
The Lag Start Delay timer of any member does not be-
gin timing until the preceding member of the system is
loaded. This is particularly useful when starting up the
system, as compressors will be started one at a time.
This sequenced starting happens if the members are
controlled by their remote inputs. If programmed for
automatic restart after power failure, the lead unit will
be delayed by the automatic restart delay, then each
additional unit will be delayed by the lag start delay.
CONNECTION TO EXTERNAL CONTROLS
The ES+ controller offers interconnection points for ex-
ternal controls and indicators. This allows simple con-
nection to remote controls and indicators, or integration
into any plantwide controls system.
Remote On / Off – Remote on–off control of the sys-
tem requires only a simple two–wire control, with an
isolated contact suitable for 120 volts, 1 amp. This may
be a switch, a timer contact, a relay contact, or a PLC
output. To connect, simply run the two wires to the con-
trol enclosure, remove the jumper between terminal 6
and terminal 9 on the terminal strip, and connect the
two wires to terminal 6 and terminal 9.
The air compressor will operate normally in its selected
mode whenever this contact is closed (turned on).
Note that the keypad is always the master control; the
operating mode must be selected at the keypad. When
the contact is opened (turned off), operation depends
on how the controller has been programmed and what
it is doing prior to opening the contact.
If the compressor was already stopped in automatic or
sequence modes, it will remain stopped and will not re-
start until the contact is closed. The display will flash
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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