Johnson Controls Penn System 450 Series, Technical Bulletin

Page: 78 / 84

Integration Constant A time-integral variable, which is applied to the proportional control only
analog output to provide Proportional plus Integral (P-I) control on the
output. The integration constant determines the rate at which the control
readjusts the output signal to drive the process to setpoint. In
well-balanced control applications with predictable loads and properly
sized equipment, P-I control provides tighter control to setpoint and a
faster response to system load changes than proportional-only control. See
Proportional Plus Integral Control and Integration Constants on page 23
and Determining the Integration Constant for an Analog Output on page
56 for more information.
INWC INWC and the sensed pressure value appears in the Main (sensor status)
screens on control systems using a sensor with a Sensor Type of P 0.5,
P 2.5, P 5, or P 10. INWC represents Inches Water Column (in.W.C.),
which is a unit of measurement for measuring very low pressures such as
building and duct static pressures and pressure differentials. See
System
450 Sensors and Transducers for Standard Control Modules on page 16
for more information.
LEV
1
In the Pulse Output Level Selection (LEV
1
) screen in the Pulse Region
Setup screens, select the Pulse Level value (as a percentage of the total
range, 0–100%) below which the output generates a pulse output signal
instead of the standard 0-10 VDC output signal that it generates for the rest
of output signal range. Select a LEV
1
value that is greater than the required
minimum speed reference for the EC motor that the output is controlling.
For example, if the minimum speed reference for your motor is 2 VDC
(20% of the 0-10 VDC signal range), select 25(%) for the LEV
1
value. The
Pulse Region Setup screens are available only on Analog Output 1 on the
hybrid analog output control module. See
Sensor Failure Mode on page 26
and Setting up a Pulse Region Hybrid Analog Output on page 55 for more
information.
Main Screens The default screens that auto-scroll on the LCD during normal control
system operation. The Main screens display the sensor status for each
hard-wired and functional sensor on standard control systems. From the
Main screens, press (repeatedly) to manually scroll through the sensor
status and output status screens. From the Main screens, press and hold
and simultaneously for 5 seconds to go to the System Setup screens. See
Accessing and Navigating the User Interface and Viewing the System
Status Screens on page 42 for more information.
Normally Closed
(N.C.) Normally Closed (N.C.) relay contacts are closed when the relay is not
energized/activated and open when the relay is energized. On System 450
Relay Outputs, the LC
y and LNC y terminals connect to the Normally
Closed contacts. See Relay Outputs on page 18 for more information.
Term Definition
78