Emerson Vission 20/20 Operation And Service Manual page 168

Appendix B • Vission 20/20 Application Procedures
master compressor ONLY. (The slave compressor(s)
load and unloading is setup in the master Compressor
Sequencing menu). The Auto-cycle settings can also be
setup for the Master Compressor, to establish settings of
when the Master compressor will automatically cycle on
and off.
The proportional control settings affect the loading
and unloading of the master compressor only. The
slave compressor loading and unloading rules are
defi ned in the Compressor Sequencing screen of the
master compressor. Also, during slave compressor
sequencing, the Auto-cycle setpoints are not active
for the slave compressors, even if Auto-cycle has
been selected. However, it may still be desirable
to check the Auto-cycle setpoints for the slave
compressors. This can be desirable if the Master
Compressor panel is powered down, and the slave
compressors then revert to "Local" control. When
the panels revert to "Local" control, then the Auto-
cycle setpoints would become active.
Figure B-7. Setup of Master Compressor for Slave Compressor(s) Loading and Unloading
B - 12
NOTE
Vission 20/20 • Operation and Service Manual •Vilter/Emerson • 35391SC 2.0
SETUP OF MASTER COMPRESSOR FOR
SEQUENCING SLAVE COMPRESSORS
Logon to the Master Compressor and navigate to the
Compressor Sequencing screen, page 2. Wait until all
slaves names show up under Equipment List on the last
page of the Compressor Sequencing menu. Use the
Refresh button to update the screen, see Figure B-7.
MASTER COMPRESSOR SEQUENCING MENU
SETUP
The master compressor loads and unloads itself based
on the proportional control settings that are set in its
own Compressor Control Setpoints menu. The Auto-
cycle Setpoints can also be enabled for the master com-
pressor, which would defi ne the setpoints for when the
master compressor will stop and start. Auto-cycle set-
tings on the slaves are not active during sequencing,
however you still may wish to select Auto-cycle on the
slave compressor for the circumstance where the power
is removed from the Master panel, and the slave com-
pressors would then revert to "Local" control.