
Manual Supplement
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Page 6 of 9 Released 10/03/01
Description of Variables
NPT - Network Point Type
Variables are defined as analog inputs, binary inputs, and analog outputs. Analog inputs are current
control parameters and items that the controller is measuring. Binary inputs represent controller
states. Analog outputs are the programmable setpoints for the isolation room pressure controller
and monitor. These setpoints can be changed through the keypad or by overriding the current
setpoint.
NPA - Network Point Address
Address of the desired point.
Change of Status (COS) - Room Pressure Analog Input
The 8636-N2 has the ability to change control setpoints locally. The alarm setpoints need to be
based on the controller’s control setpoint (AI #4). For example the setpoint could go from -0.002
“H2O to +0.001 “H2O. If the COS alarm setpoints are not changed to accommodate you could get
low alarm or low warning messages when the unit is working correctly. If these alarm points are
set outside of the negative and positive setpoint values, incorrect alarm messages can be prevented.
Override Analog Input Command
Analog Input values can be set using the override command. These values will be reset to the
correct items when the Override is released. There is not a time-out on the override command.
Override Binary Input Command
Overriding a 1 to Emergency binary inputs enables that mode. To release the controller from
emergency state, override a 0 to the Emergency input or press either the emergency or reset key.
Releasing the override will return the controller to the Normal state. If the 8636-N2 had been put
into Emergency mode from the keypad, then it cannot be cleared remotely.
Overriding a 1 to Room Mode binary inputs enables Remote mode. To release the controller from
remote state, override a 0 to the Room Mode. Releasing the override will return the controller to
the Normal state.
Overriding a 1 to the Occupied/Unoccupied Mode binary inputs enables the unoccupied mode. To
release the controller from the unoccupied state, override a 0 to the Occupied/Unoccupied Mode.
The Occupied/Unoccupied Mode can only be accessed through N2 communications.
The alarm and data error variables can be overridden, but this will not affect the controller.
Overriding the low alarm variable will result in a change of status, but will not put the controller
into low alarm mode. The local alarm modes can only be controlled locally. Only override these
variables for diagnostic purposes, and release them for normal operation.