Carrier WEATHERMASTER 48/50Z030-105 Operation And Service Manual page 63

slowing down the fan has the additional benefit of working
around dehumidification concerns.
Static Pressure Reset Economizer Position (SP.EC) — This
option effectively resets ECONOMIN to fully occupied venti-
lation position, to account for the drop in static pressure during
static pressure reset control. The static pressure reset for the
calculation cannot be larger than the supply air static set point
(SPSP).
The calculation is as follows:
(Static Pressure Reset/SPSP) x (ECONOSPR – ECONOMIN)
As an example, the static pressure set point (SPSP) =
1.5 in. wg. The current static pressure reset is set to 0.5 in. wg.
The settings for ECONOSPR = 50% and ECONOMIN = 20%.
Therefore, the amount to add to the economizer's
ECONOMIN configuration is: (0.5/1.5) x (50-20) = 10%. In
effect, for the positioning of the economizer, ECONOMIN
would now be replaced by ECONOMIN + 10%.
Static Pressure PID Config (S.PID) — Static pressure PID
configuration can be accessed under this heading in the Con-
→
figuration SP submenu. Under most operating conditions the
control PID factors will not require any adjustment and the
factory defaults should be used. If persistent static pressure
fluctuations are detected, small changes to these factors may
improve performance. Decreasing the factors generally reduce
the responsiveness of the control loop, while increasing the
factors increase its responsiveness. Note the existing settings
before making changes, and seek technical assistance from
Carrier before making significant changes to these factors.
Static Pressure PID Run Rate (S.PID
number of seconds between duct static pressure readings taken
by the ComfortLink PID routine.
Static Pressure Proportional Gain (S.PID
the proportional gain for the static pressure control PID control
loop.
Static Pressure Integral Gain (S.PID
integral gain for the static pressure control PID control loop.
Static Pressure Derivative Gain (S.PID
derivative gain for the static pressure control PID control loop.
IGV Actuator Configs (ACT.C) — Every actuator used in the
Z Series control system has its own unique serial number. The
rooftop control uses this serial number to communicate with
the actuator over the local equipment network (LEN). These
serial numbers are programmed at the factory and should not
need changing. Should field replacement of an actuator
become necessary, it will be necessary to configure the serial
numbers of the new actuator. Five individual numbers make up
this serial number and these can be programmed to match the
serial number of the actuator in its "IGV Actuator Configs"
group, ACT.C (SN.1, SN.2, SN.3, SN.4, SN.5).
NOTE: The serial numbers for all LEN actuators can be found
inside the control doors of the unit as well as on the actuator
itself. If an actuator is replaced in the field, it is a good idea
to remove the additional peel-off serial number sticker on
the actuator and use it to replace the old one inside the
control panel doors. The format for the overall serial number
is 111-222-333-444-555, where each of these segments can
be 1, 2 or 3 digits in length. Valid numbers are in the range
1-255.
IGV Serial Number 1 (ACT.C
the first of the five segments of the IGV digital LEN actuator
serial number. The complete serial number is used by the
ComfortLink controls to communicate with the actuator.
IGV Serial Number 2 (ACT.C
the second segment of the IGV actuator serial number.
IGV Serial Number 3 (ACT.C
the third segment of the IGV actuator serial number.
→
SP.TM) — This is the
→
SP.P) — This is
→
SP.I) — This is the
→
SP.D) — This is the
→
SN.1) — This variable records
→
SN.2) — This variable records
→
SN.3) — This variable records
IGV Serial Number 4 (ACT.C
the fourth segment of the IGV actuator serial number.
IGV Serial Number 5 (ACT.C
the fifth segment of the IGV actuator serial number.
IGV Control Angle Low Limit (ACT.C
actuator learns what its end stops are though a calibration at the
factory. Field-installed actuators may be calibrated in the
Service Test mode. When an actuator learns its end stops
through this internal calibration, it remembers what its "control
angle range" is. From then on, the actuator will resolve this
control angle and express its operation in a percentage (%) of
this learned range.
If the IGV has not learned a sufficient control angle range
during calibration, it will be unable to control itself properly.
For this reason the IGV actuator used in the Z Series control
system has a configurable control angle alarm low limit in its
"Economizer Actuator Configs" group, ACT.C. (C.A.LM). If
the control angle learned through calibration is less than
→ →
Configuration SP
and the actuator will not function.
NOTE: This configuration does not typically need adjustment.
It is configurable for the small number of jobs which may
require a custom solution or workaround.
STATIC PRESSURE RESET — The configuration for Static
Pressure Reset is found under Configuration
ITEM EXPANSION
Static Press.
→ →
SENS SP.RS
Reset Sensor.
Static Pressure Reset Sensor (SP.RS) — If the outdoor air
quality sensor is not configured (Configuration
→ →
AQ.CF OQ.A.C=0), then it is possible to use the outdoor
air quality sensor location on the CEM board to perform static
pressure reset via an external 4-20 mA input. Enabling this
sensor will give the user the ability to reset from 0 to 3-in. wg
of static pressure. The reset will apply to the supply static
pressure set point (Configuration
= 0-in. wg and 20 mA = 3-in. wg.
As an example, the static pressure reset input is measuring
6 mA, and the input is resetting 2 mA of its 16 mA control
range. The 4 to 20 mA range corresponds directly to the 0 to
3 in. wg of reset. Therefore 2 mA reset is 2/16 * 3-in. wg =
0.375-in. wg of reset. If the static pressure set point (SP.SP) =
1.5-in. wg, then the static pressure control point for the system
will be reset 1.5 – 0.375 = 1.125-in. wg.
For third party 4 to 20 mA SP reset, wire the input to TB203
terminals 6 and 7.
For reset via a connected ComfortID™ system, the Linkage
Coordinator terminal monitors the primary-air damper position
of all the terminals in the system. It then calculates the amount of
supply static pressure reduction necessary to cause the most
open damper in the system to open more than the minimum
value (60%) but not more than the maximum value (90% or neg-
ligible static pressure drop). This is a dynamic calculation, which
occurs every two minutes whenever the system is operating. It
ensures that the supply static is sufficient to supply the required
airflow at the worst case terminal but not more than necessary, so
that the air terminals do not have to operate with a pressure drop
greater than required to maintain the airflow set point of each
individual terminal in the system. As the system operates, if the
most open damper opens more than 90%, the system recalcu-
lates the pressure reduction variable and Configuration
→ →
SENS SP.RS, the amount of reset, is reduced. If the most
open damper closes to less than 60%, the system recalculates the
pressure reduction variable and SP.RS is increased.
With this system, one needs to enter as the static pressure set
point SP.SP either a maximum duct design pressure or maxi-
mum equipment pressure, whichever is less. The system will
63
→
SN.4) — This variable records
→
SN.5) — This variable records
→
C.A.LM) — The IGV
→
ACT.C C.A.LM, an alert will occur
→
UNIT.
RANGE CCN POINT
Enable/
SPRSTSEN
Disable
→ →
SP SP.SP), where 4 mA
DEFAULT
Disable
→
IAQ
→
UNIT