4.2.6.5 - Master/Slave configuration table
The MST_SLV table can be accessed through the Modify Controller menu of the Network Service Tool or the
main interface. This table needs to be configured if the master/slave function is used. Master/slave function
allows the Pro-Dialog unit to operate as master or a slave in a two chillers plant. See section 4.20.
TABLE NAME: MST_SLV PIC TABLE TYPE : 10H, instance 3
DESCRIPTION
STATUS
DEFAULT
UNITS
POINT
1
MASTER/SLAVE CONTROL
2
3
Master/Slave Select:
0/1/2
1
0
-
ms_sel
4
0 = Disable
5
1 = Master
6
2 = Slave
7
Master Control Type:
1/2/3
1
-
ms_ctrl
8
1 = Local Control
9
2 = Remote Control
10
3 = CCN Control
11
Slave Address
1 to 236
1
-
slv_addr
12
Lag Start Timer
2 to 30
2
10
min
lstr_tim
13
Lead/Lag Balance
Yes/No
3
No
-
ll_bal
14
Lead/Lag Balance Delta
40 to 400
4
168
hours
ll_bal_d
15
Lag Unit Pump Control
0/1
0
-
lag_pump
16
0 = Stop if Unit Stops
17
1 = Run if Unit Stops
18
Lead Pulldown Time
0 to 60
5
0
minutes
lead_pul
Decisions description:
1.
This decision allows the unit to operate as master or a slave in a two chillers master/slave. The master
chiller monitors all external commands as start/stop, demand limiting, setpoint select or reset via CCN bus.
Control of the slave chiller is done through commands (start/stop, demand limit, setpoint, heat cool)
emitted by the master chiller. The slave will not be allowed to operate as a slave if its CHIL_S_S,
CTRL_PNT or DEM_LIM, HC_SEL variables has a force priority higher than a control force.
2.
This timer is started when all conditions to start the lag chiller are satisfied. Lag chiller shall not be started
until this timer is elapsed. To be set in the master unit table only.
3.
This decision allows to activate two chillers lead/lag balance function. It is used for master/slave chiller
running time equalization. When this function is active, once per day or each time the master chiller is
switched from the off to the on state the control determines the lead chiller based on both chillers run hours
delta. When the run hours delta is greater than the configured lead/lag balance delta then a changeover
will occur and the unit with the smallest operating hours value will become the lead. This function cannot
operate if the master chiller demand limit is less than 100%. In that case, the master chiller will always be
the lead. To be set in the master unit table only.
4.
This function allows to set the lead/lag balance delta used for master/slave chiller running time
equalization. Lead/lag changeover occurs when the lead/lag operating time delta overlaps the configured
balance value and provided that master unit is not under demand limit control.
5.
This decision allows to set the lead chiller pull down duration before the lag chiller starts.
©
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ARRIER
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.
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PERSONS
OUTSIDE
CARRIER
ORGANIZATION
CARRIER SA
USER'S GUIDE FOR
30GX&HX PRO_DIALOG 4 V.2
ECG - UG - 02 - 02
Rev: Original
Page: 35 /98
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