Emerson VILTER MicroVission Operation And Service Manual page 247

Appendix D • Compressor Sequencing Setup
"1" is highest priority.
Compressor with priority "2" has higher priority
than compressor with priority "3".
The Comp1 (being highest priority device)
program monitors its suction pressure value.
During load cycle when suction is below the
configured start offset value (22+6 = 28 psig), then
also the Comp1 starts running in auto sequencing
with the minimum step (bypassing this setpoint)
and start loading compressor Comp1 according
to load offset and load interval when suction press
goes above setpoint(22 + 2 Psig). Program loads
Comp1 as per steps configured till it reaches its full
load/ maximum step. Once Comp1 starts running
at full load and suction pressure is still above Start
Pressure Offset ( i.e. > start offset value of 22+6 =
28 psig), then second highest priority compressor
Comp2 starts monitoring suction pressure against
start offset for start time (90 sec ) period. This
process is continued till either setpoint is achieved
or all compressors are running at their full load/
maximum step. Refer Figure D-5 for load cycle
status details.
MicroVission Controller • Operation and Service Manual • Emerson • 35391MV 1.3
NOTE
Figure D-5. Compressor(s) Load Cycle in Sequencing
D − 7