Orion System RNE Modular Controller - Manual (Page 69)

RNE Modular Controller Field Technical Guide
SEQUENCE OF OPERATION
69
Force Modes or Overrides
WARNING: No equipment protection is available during the
Force Mode of operation. That means you could start a compressor
without running the Supply Fan or could create other conditions
that WILL damage the equipment. WattMaster Controls assumes
no responsibility or liability for the misuse of Overrides that cause
damage to the equipment!
The RNE Controller relay and analog outputs can be user-overridden if
the Modular Service Tool or the Prism Computer Front-End Software
is used. The System Manager cannot be used for these Force Modes.
The Modes of operation for the relays are as follows:
0 = Normal Operation
1 = Forced ON
2 = Forced OFF
The Analog Outputs are Forced when you specify a value between 0.0
and 10.0 VDC. To cancel the Force Mode, you must enter a value less
than zero, such as -1.0 VDC.
When the Analog Outputs are Forced, the display on the Modular Service
Tool or Prism program can be interpreted as the actual voltage. During
normal operation, the display indicates the percentage signal applied
based on the user-defi ned voltage limits. For example, if you defi ne a
2.0 VDC to 10.0 VDC range, then 50% would be 6.0 VDC instead of
the 5.0 VDC applied when the range is 0.0 VDC to 10.0 VDC.
As previously mentioned, Force Modes can only be activated when us-
ing either the Modular Service Tool or the Prism Computer Front-End
Software. Furthermore, the Override condition can only remain in effect
as long as one of these Operator Interface devices is connected and com-
municating with the RNE. That means that you cannot Force an Override
condition and then walk away from the equipment with the Override
still active. The loss of communications, removal, or shutdown of the
Operator Interface will automatically terminate the Override within 10
minutes. This protects the equipment and prevents an Override condition
from remaining active indefi nitely, resulting in ineffi cient or dangerous
operation of the equipment.
VAV Terminal Unit Controller
Compatibility
The RNE Controller is designed to communicate with Orion VAV/Zone
Controllers. The RNE can be confi gured to broadcast its Internal Sched-
ule, Time, and Date, Fan and Heat Status, and Supply Air Temperature.
The RNE can also broadcast Force to Max or Force to Fixed Position
during Morning Warm-up. The Orion VAV/Zone Controllers broadcast
Push-Button Overrides from Unoccupied to Occupied. The controllers
can also generate Unoccupied Heating and Cooling calls to the RNE
Controller based on Setbacks.
Force Modes / Overrides & VAV/Zone System
If you are using another manufacturer’s VAV Terminal Unit Controllers,
the RNE Controller can activate a relay to inform the VAV/Zone Control-
lers that the RNE Controller is operating in Warm-up Mode. No other
information can be passed between the RNE Controller and the other
manufacturer’s VAV Terminal Unit Controllers. This means that Over-
rides or Unoccupied Heating and Cooling calls cannot activate the RNE
Controller. If you need any of these capabilities, you must use only Orion
VAV/Zone Controllers for controlling all of your VAV Terminal Units.
VAV/Zone System
When the RNE goes into the Occupied Mode, it initiates Morning
Warm-up if the Return Air Temperature is below the Morning Warm-
up Target Temperature Setpoint. During Morning Warm-Up, the VAV/
Zone Controllers will modulate open if the Space Temperatures are too
cold. They can also move to their Maximum Airfl ow or Fixed Airfl ow
Position Setpoint if they receive this broadcast from the RNE Controller.
Once Morning Warm-up has been satisfi ed, the RNE enters the Cool-
ing Mode and the VAV/Zone Controllers will modulate to satisfy their
Space Temperature Setpoints. If the Space Temperature falls below
the Heating Setpoint, staged or modulating Reheat can be activated to
warm the space.
Communications between the RNE and the VAV/Zone Controllers are
handled by the MiniLink Polling Device. Alarm Polling and Tenant
Overrides are also monitored by the MiniLink Polling Device. Tenant
Overrides are overrides generated by the Space Temperature Sensor’s
push button. The MiniLink Polling Device records the start and stop
times and total run times of the overrides on a daily and monthly basis.
A computer running Prism Computer Front-End Software is required to
retrieve all data acquired by the MiniLink Polling Device.
Zoning System
The RNE Controller automatically confi gures itself for Voting Control
when the MiniLink Polling Device is installed and is confi gured as a
Voting System. The RNE Controller sets the HVAC Mode Enable to the
Return Air Temperature Sensor as soon as communication is acquired with
the MiniLink Polling Device. If the VAV/Zone controllers are confi gured
for Voting, the MiniLink Polling Device totals the Heating and Cooling
demands and determines which HVAC Mode the RNE should be in. The
MiniLink Polling Device broadcasts a forced Heating, Cooling, or Vent
Mode of operation to the RNE. Once the RNE receives the broadcast
to set the HVAC Mode, it operates as previously described in the RNE
Sequence of Operations. If communications are lost, the RNE returns
to its own control and will maintain the HVAC Mode Enable Setpoints
by using the Return Air Temperature Sensor as the Controlling Sensor.