Emerson Vission 20/20 Operation And Service Manual page 172

Appendix B • Vission 20/20 Application Procedures
(decrease) the slave compressor capacity . When a
slave compressor has been unloaded to its MIN CAP
setpoint, and the suction pressure is still less than a
value of unload rate 1 offset for the time period of
the unload rate 1 timer, a calculation of the operat-
ing CFM of the slave compressor is made. This value
is compared against the available CFM of the other
running compressors. If enough CFM is available,
then the machine stop timer is started. When it
times out, and provided there is still enough CFM
available from the remaining running compressors,
the slave compressor is stopped.
MACHINE START / STOP TIMER
• Machine start / stop timers show the time in sec that
the Master Compressor will hold before starting /
stopping slave compressor once (Start / Stop ) deci-
sion is taken. See also Walk-through of Sequencing
Loading and Unloading for further explanation of the
operation of these timers.
Status Symbols shown
Sequencing menu, showing status of Slave compressors:
B - 16
on Master Compressor
Table B-1. Status Symbols
Slave Compressor is detected but is not confi gured in the sequencing
table
Default, If slave is not present
Slave Compressor is confi gured in sequencing table but is not confi g-
ured in "Remote" mode
Slave Compressor confi gured in sequencing table and is in ready to run
state. You'll normally see this icon when you have initiated Compressor
Sequencing on the Master compressor by pressing the green Unit
Start button and then the Auto Seq button
Slave Compressor is running with Alarm condition
Slave Compressor stopped due to Error Condition
Slave Compressor running at maximum capacity without any error
Slave Compressor under active control of Master Compressor
Slave Compressor running into its stop timer, will be stopped
Vission 20/20 • Operation and Service Manual •Vilter/Emerson • 35391SC 2.0
Before confi guring the Compressor Sequencing
table on the master compressor, log on to slave
compressors one by one and enable the sequencing
in slave mode from the Confi guration screen, then
put each slave in Remote mode. Then log onto the
master compressor and wait until all slave names
show up in the Equipment List table.
CONFIGURING SEQUENCING TABLE ON MASTER
COMPRESSOR
1. Select correct compressor name from Equipment
drop down list.
2. Assign Priority for the slave compressor
3. Assign Step size in percentage for the slave
compressor
4. Assign Min/ Max capacity values for the slave
compressor
5. Repeat steps #1-4 to confi gure all slave compressors.
6. Once the sequencing table is confi gured, the status
for every confi gured compressor should show "+"
symbol.
NOTE