16
|
Primary-secondary (PS) mode
Note:
during normal operation, in both the primary-secondary (PS) and lead-lag (LL) operating modes, line
2
displays the device ID, not the
outlet temperature. The outlet temperature can be viewed on line
1
by pressing
arrow.
Primary-secondary (PS) mode shares the same hardware and source code as standalone mode, but offers more functionality and features.
The controller ships from the factory in Standalone Mode. PS mode is configured manually in the field after the installation. This option
allows the user to operate the air conditioner in a group network with up to
10
units. To support PS mode, three parameters,
H
01
,
H
02
, and
H
03
need to be configured.
H
01
specifies the operating mode,
H
02
specifies the device ID, and
H
03
specifies the total number of the units in
the group network.
Before configuring to operate in PS mode, the user should understand the functionality of the PS mode.
1. In the PS mode, all units operate off the cooling/heating setpoint and differential of the primary unit. The system prevents setpoint
changes from secondary units.
2. The primary unit monitors the enclosure temperatures of all the units and manages the ON/OFF status of cooling and heating based on
the unit reporting the highest temperature.
3. When cooling is initiated the primary unit energizes first. Secondary units are energized sequentially at
10
second intervals. When heating
is initiated all units turn on heat together. When cooling or heating is satisfied all units turn off together.
4. If the number of units communicating on the network doesn’t match the value in H
03
then the primary unit will display alarm LC, and the
secondary units will display alarm LC
1
until the communication re-established.
5. Any unit that loses communication with the primary unit will enter standalone mode and continue operating based on its own temperature
probe until communication is re-established.
6. All temperature setpoints and alarms can be viewed remotely if one of the ACUs is equipped with nVent HOFFMAN network card
(RAC module).
7. Best recommendation is to configure the ACU that has nVent HOFFMAN network card to be the primary one.
Connecting units together in primary/secondary mode
Primary - Device ID
1
Secondary - Device ID
2
Secondary - Device ID
3
Secondary - Device ID
10
Figure
2
Primary-secondary network connectivity
