43
Table 47 — Run Status Cool Display
Current Running Capacity (C.CAP)
This variable represents the amount of capacity in percent that
is currently running.
Current Cool Stage (CUR.S)
This variable represents the cool stage currently running.
Maximum Cool Stages (MAX.S)
This variable is the maximum number of cooling stages the
control is configured for and capable of controlling.
Active Demand Limit (DEM.L)
If demand limit is active, this variable will represent the
amount of capacity that the control is currently limited to.
Capacity Load Factor (SMZ)
This factor builds up or down over time (–100 to +100) and is
used as the means of adding or subtracting a cooling stage
during run time. It is a normalized representation of the rela-
tionship between “Sum” and “Z.”
Next Stage EDT Decrease (ADD.R)
This variable represents (if adding a stage of cooling) how
much the temperature should drop in degrees depending on the
R.PCT calculation and exactly how much additional capacity
is to be added.
ADD.R = R.PCT * (C.CAP — capacity after adding a cooling
stage)
For example: If R.PCT = 0.2 and the control would be adding
20% cooling capacity by taking the next step up, 0.2 times 20 =
4°F (ADD.R).
Next Stage EDT Increase (SUB.R)
This variable represents (if subtracting a stage of cooling)
how much the temperature should rise in degrees depending
on the R.PCT calculation and exactly how much capacity is
to be subtracted.
SUB.R = R.PCT * (C.CAP — capacity after subtracting a
cooling stage)
For Example: If R.PCT = 0.2 and the control would be subtract-
ing 30% capacity by taking the next step down, 0.2 times –30 =
–6°F (SUB.R).
Rise Per Percent Capacity (R.PCT)
This is a real time calculation that represents the amount of de-
grees of drop/rise across the evaporator coil versus percent of
current running capacity.
R.PCT = (MAT – EDT)/ C.CAP
Cap Deadband Subtracting (Y.MIN)
This is a control variable used for Low Temp Override
(L.TMP) and Slow Change Override (SLOW).
Y.MIN = -SUB.R*0.4375
Cap Deadband Adding (Y.PLU)
This is a control variable used for High Temp Override
(H.TMP) and Slow Change Override (SLOW).
Y.PLU = -ADD.R*0.4375
Cap Threshold Subtracting (Z.MIN)
This parameter is used in the calculation of SumZ and is calcu-
lated as follows:
Z.MIN = Configuration
COOL
Z.GN * (–10 + (4*
(-SUB.R))) * 0.6
Cap Threshold Adding (Z.PLU)
This parameter is used in the calculation of SumZ and is calcu-
lated as follows:
Z.PLU = Configuration
COOL
Z.GN * (10 + (4*
(-ADD.R))) * 0.6
High Temp Cap Override (H.TMP)
If stages of mechanical cooling are on and the error is greater
than twice Y.PLU, and the rate of change of error is greater
than 0.5F per minute, then a stage of mechanical cooling will
be added every 30 seconds. This override is intended to react to
situations where the load rapidly increases.
Low Temp Cap Override (L.TMP)
If the error is less than twice Y.MIN, and the rate of change of
error is less than –0.5F per minute, then a mechanical stage
will be removed every 30 seconds. This override is intended to
quickly react to situations where the load is rapidly reduced.
Pull Down Cap Override (PULL)
If the error from setpoint is above 4F, and the rate of change
is less than –1F per minute, then pulldown is in effect, and
“SUM” is set to 0. This keeps mechanical cooling stages from
being added when the error is very large, but there is no load in
ITEM EXPANSION RANGE UNITS CCN POINT WRITE STATUS
COOL COOLING INFORMATION
C.CAP Current Running Capacity % CAPTOTAL
CUR.S Current Cool Stage COOL_STG
MAX.S Maximum Cool Stages CLMAXSTG
DEM.L Active Demand Limit % DEM_LIM forcible
SUMZ COOL CAP. STAGE CONTROL
SMZ Capacity Load Factor -100 – +100 SMZ
ADD.R Next Stage EDT Decrease ^F ADDRISE
SUB.R Next Stage EDT Increase ^F SUBRISE
R.PCT Rise Per Percent Capacity RISE_PCT
Y.MIN Cap Deadband Subtracting Y_MINUS
Y.PLU Cap Deadband Adding Y_PLUS
Z.MIN Cap Threshold Subtracting Z_MINUS
Z.PLU Cap Threshold Adding Z_PLUS
H.TMP High Temp Cap Override HI_TEMP
L.TMP Low Temp Cap Override LOW_TEMP
PULL Pull Down Cap Override PULLDOWN
SLOW Slow Change Cap Override SLO_CHNG
HMZR HUMIDIMIZER
CAPC Humidimizer Capacity HMZRCAPC
C.EXV Condenser EXV Position COND_EXV
B.EXV Bypass EXV Position BYP_EXV
RHV Humidimizer 3-Way Valve HUM3WVAL
C.CPT Cooling Control Point COOLCPNT
EDT Evaporator Discharge Tmp EDT
H.CPT Heating Control Point HEATCPNT
LAT Leaving Air Temperature LAT
To Next Page
Loading...
