Johnson Controls Penn System 450 Series Technical Bulletin page 83

Term
Sn-1
Sn-2
Sn-3
Sn-d
x
SNF
Definition
Input Sensor 1 (Sn-1) as identified in the System 450 UI. Outputs that
reference Sn-1 reference the sensor or transducer that is hard-wired to the
Sn1 terminal and a Common (C) terminal on the low-voltage terminal
block on the system's control module. On standard System 450 control
systems, the Sn-1 sensor is also used to create the functional Differential
Control sensor (Sn-d) and the High Input Signal Selection feature (HI-2,
HI-3). See System 450 Compatible Sensors and Transducers on page 15
and Setting Up the Sensors and Transducers on page 45 for more
information.
Input Sensor 2 (Sn-2) as identified in the System 450 UI. Outputs that
reference Sn-2 reference the sensor or transducer that is hard wired to the
Sn2 terminal and a Common (C) terminal on the low-voltage terminal
block on the system's control module. On standard System 450 control
systems, the Sn-2 sensor is also used to create the functional Differential
Control sensor (Sn-d) and the High Input Signal Selection feature (HI-2,
HI-3). See System 450 Compatible Sensors and Transducers on page 15
and Setting Up the Sensors and Transducers on page 45 for more
information.
Input Sensor 3 (Sn-3) as identified in the System 450 UI. Outputs that
reference Sn-3, reference the sensor or transducer that is hard wired to the
Sn3 terminal and a Common (C) terminal on the low-voltage terminal
block on the system's control module. On standard System 450 control
systems, the Sn-3 sensor is also used to create the High Input Signal
Selection feature (HI-3). See System 450 Compatible Sensors and
Transducers on page 15 and Setting Up the Sensors and Transducers on
page 45 for more information.
The functional Differential Control sensor (Sn-d) as identified in the
System 450 UI. Sn-d is available on standard System 450 control systems
(only), when Sn-1 and Sn-2 are the same Sensor Type. The differential
control value (Sn-d) is defined as Sn-d = (Sn-1) - (Sn-2). Differential
Control is available only on standard control modules. See Differential
Control on page 25, Sensor Failure Mode on page 26, and Setting Up the
Sensors and Transducers on page 45 for more information.
In the Sensor Failure Mode (SNF
select the mode of operation for output x in the event that a sensor (or
associated sensor wiring) that the output references fails. SNF modes for
relay outputs are ON and OFF. SNF modes for analog outputs are
ON (=OEP) or OFF (=OSP). SNF modes for outputs that reference the
Reset Setpoint (RSP) are MXSP for reverse acting RSP or MNSP for
direct acting RSP. See Sensor Failure Mode on page 26 for more
information.
x
) screen in the Output Setup screens,
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