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TECHNICAL

Valve Position Bright/Dim Illumination Control

Normal Operation:

Some indicators require three states of illumination to show positional information. The three states are OFF, DIM and BRIGHT. The indicator voltages for each state:

BRIGHT = 28v DC

DIM = 16v DC

OFF = 0 v DC

The indicators that provide three states of illumination are not wired to S3 "MASTER BRIGHT/DIM/TEST LIGHTS SWITCH" control (Instrument Panel P1-2) for setting indicator brightness. Indicator brightness is ONLY controlled by the valve position that the indicator is monitoring. They are wired to S3 "MASTER BRIGHT/DIM/TEST LIGHTS SWITCH" for the "TEST" function.

The crossfeed valve open light is an example of a indicator using three states of illumination.

Example:

FUNCTIONAL DESCRIPTION - FUEL CROSSFEED VALVE

General

The fuel crossfeed valve switch controls the crossfeed valve. When you move the switch to the open or closed position, 28v dc power goes through a switch assembly to the actuator. The actuator then moves the crossfeed valve to the applicable position.

The printed circuit card assembly controls the operation of the crossfeed valve open light. The printed circuit assembly receives fuel crossfeed valve position and fuel crossfeed valve switch position information.

When the fuel crossfeed valve is closed, the crossfeed valve open light is off (zero volts). When the fuel crossfeed valve position and fuel crossfeed valve switch position disagree, the crossfeed valve open light is on bright (twenty eight volts). When the fuel crossfeed valve is open, the crossfeed valve open light is on dim (sixteen volts).

Indicator Locations:

LOC Module # ID # Legend Illumination Description

FUEL P5-2 L10 ENG VALVE CLOSED OFF 0 vdc ENGINE 1 FUEL VALVE IS OPEN

DIM 16vdc ENGINE 1 FUEL VALVE IS CLOSED

BRIGHT 24vdc ENGINE 1 FUEL VALVE IS IN TRANSIT

OR VALVE AND SWITCH DISAGREE

FUEL P5-2 L1 SPAR VALVE CLOSED OFF 0 vdc ENGINE 1 SPAR FUEL VALVE IS OPEN

DIM 16vdc ENGINE 1 SPAR FUEL VALVE IS CLOSED

BRIGHT 24vdc ENGINE 1 SPAR FUEL VALVE IS IN TRANSIT

OR VALVE AND SWITCH DISAGREE

FUEL P5-2 L11 ENG VALVE CLOSED OFF 0 vdc ENGINE 2 FUEL VALVE IS OPEN

DIM 16vdc ENGINE 2 FUEL VALVE IS CLOSED

BRIGHT 24vdc ENGINE 2 FUEL VALVE IS IN TRANSIT

OR VALVE AND SWITCH DISAGREE

FUEL P5-2 L2 SPAR VALVE CLOSED OFF 0 vdc ENGINE 2 SPAR FUEL VALVE IS OPEN

DIM 16vdc ENGINE 2 SPAR FUEL VALVE IS CLOSED

BRIGHT 24vdc ENGINE 2 SPAR FUEL VALVE IS IN TRANSIT

OR VALVE AND SWITCH DISAGREE

FUEL P5-2 L3 VALVE OPEN OFF 0 vdc CROSSFEED VALVE IS CLOSED

DIM 16vdc CROSSFEED VALVE IS OPEN

BRIGHT 24vdc CROSSFEED VALVE IS IN TRANSIT

OR VALVE AND SWITCH DISAGREE

ICE P5-11 L6 L VALVE OPEN OFF 0 vdc LEFT WING VALVE IS CLOSED

DIM 16vdc LEFT WING VALVE IS OPEN

BRIGHT 24vdc LEFT WING VALVE IN TRANSIT

OR VALVE AND SWITCH DISAGREE

ICE P5-11 L4 R VALVE OPEN OFF 0 vdc RIGHT WING VALVE IS CLOSED

DIM 16vdc RIGHT WING VALVE IS OPEN

BRIGHT 24vdc RIGHT WING VALVE IN TRANSIT

OR VALVE AND SWITCH DISAGREE

ICE P5-11 L1 COWL VALVE OPEN OFF 0 vdc ENGINE 1 COWL VALVE CLOSED

DIM 16vdc ENGINE 1 COWL VALVE OPEN

BRIGHT 24vdc ENGINE 1 COWL VALVE IN TRANSIT

OR VALVE AND SWITCH DISAGREE

ICE P5-11 L2 COWL VALVE OPEN OFF 0 vdc ENGINE 2 COWL VALVE CLOSED

DIM 16vdc ENGINE 2 COWL VALVE OPEN

BRIGHT 24vdc ENGINE 2 COWL VALVE IN TRANSIT

OR VALVE AND SWITCH DISAGREE

Simulator Solution:

A 12V Zener diode could be used to provide the reduction in Brightness for the Dim mode. This 12v zener diode could be wired to terminal number two (2) of a Korry 318 Chromalux® indicator "Circuit type 1" in series with a single pole switch to ground. A second switch could be wired in parallel with the 12v zener diode, and when it is closed the Bright mode (28V) would result.

WIRING DIAGRAM KORRY 318 CIRCUIT TYPE 1 INDICATOR

Logic Table for Korry Indicator legend "VALVE CLOSED"

VALVE POSITION 12V Zener Switch 1 (S1) Switch 2 (S2) ILLUMINATION

OPEN OPEN OPEN OFF

TRANSIT OPEN OR CLOSED See Note 1 CLOSED BRIGHT

CLOSED CLOSED OPEN DIM

Note 1: For more realistic operation close S1 and S2 for BRIGHT, then open S2 for DIM, or both S1, S2 for OFF

Logic Table for Korry Indicator legend "VALVE OPEN"

VALVE POSITION 12V Zener Switch 1 Switch 2 ILLUMINATION

CLOSED OPEN OPEN OFF

TRANSIT OPEN OR CLOSED See Note 1 CLOSED BRIGHT

OPEN CLOSED OPEN DIM

Note 1: For more realistic operation close S1 and S2 for BRIGHT, then open S2 for DIM, or both S1, S2 for OFF

BOTH VALVES IN TRANSIT

LEFT VALVE IN TRANSIT RIGHT VALVE OPEN

BOTH VALVES OPEN

12V ZENER DIODES

WIRING DIAGRAM KORRY CIRCUIT TYPE 1 INDICATOR

Chromalux® is a registered trademark of Korry Electronics Co.

Normal Operation:

Some indicators require three states of illumination to show positional information. The three states are OFF, DIM and BRIGHT. The indicator voltages for each state:
BRIGHT = 28v DC
DIM = 16v DC
OFF = 0 v DC
The indicators that provide three states of illumination are not wired to S3 "MASTER BRIGHT/DIM/TEST LIGHTS SWITCH" control (Instrument Panel P1-2) for setting indicator brightness. Indicator brightness is ONLY controlled by the valve position that the indicator is monitoring. They are wired to S3 "MASTER BRIGHT/DIM/TEST LIGHTS SWITCH" for the "TEST" function.
The crossfeed valve open light is an example of a indicator using three states of illumination.

Example:

FUNCTIONAL DESCRIPTION - FUEL CROSSFEED VALVE
General
The fuel crossfeed valve switch controls the crossfeed valve. When you move the switch to the open or closed position, 28v dc power goes through a switch assembly to the actuator. The actuator then moves the crossfeed valve to the applicable position.
The printed circuit card assembly controls the operation of the crossfeed valve open light. The printed circuit assembly receives fuel crossfeed valve position and fuel crossfeed valve switch position information.
When the fuel crossfeed valve is closed, the crossfeed valve open light is off (zero volts). When the fuel crossfeed valve position and fuel crossfeed valve switch position disagree, the crossfeed valve open light is on bright (twenty eight volts). When the fuel crossfeed valve is open, the crossfeed valve open light is on dim (sixteen volts).

Indicator Locations:

LOC	Module #	ID #	Legend	Illumination	Description
FUEL	P5-2	L10	ENG VALVE CLOSED	OFF 0 vdc	ENGINE 1 FUEL VALVE IS OPEN
				DIM 16vdc	ENGINE 1 FUEL VALVE IS CLOSED
				BRIGHT 24vdc	ENGINE 1 FUEL VALVE IS IN TRANSIT
					OR VALVE AND SWITCH DISAGREE

FUEL	P5-2	L1	SPAR VALVE CLOSED	OFF 0 vdc	ENGINE 1 SPAR FUEL VALVE IS OPEN
				DIM 16vdc	ENGINE 1 SPAR FUEL VALVE IS CLOSED
				BRIGHT 24vdc	ENGINE 1 SPAR FUEL VALVE IS IN TRANSIT
					OR VALVE AND SWITCH DISAGREE

FUEL	P5-2	L11	ENG VALVE CLOSED	OFF 0 vdc	ENGINE 2 FUEL VALVE IS OPEN
				DIM 16vdc	ENGINE 2 FUEL VALVE IS CLOSED
				BRIGHT 24vdc	ENGINE 2 FUEL VALVE IS IN TRANSIT
					OR VALVE AND SWITCH DISAGREE

FUEL	P5-2	L2	SPAR VALVE CLOSED	OFF 0 vdc	ENGINE 2 SPAR FUEL VALVE IS OPEN
				DIM 16vdc	ENGINE 2 SPAR FUEL VALVE IS CLOSED
				BRIGHT 24vdc	ENGINE 2 SPAR FUEL VALVE IS IN TRANSIT
					OR VALVE AND SWITCH DISAGREE

FUEL	P5-2	L3	VALVE OPEN	OFF 0 vdc	CROSSFEED VALVE IS CLOSED
				DIM 16vdc	CROSSFEED VALVE IS OPEN
				BRIGHT 24vdc	CROSSFEED VALVE IS IN TRANSIT
					OR VALVE AND SWITCH DISAGREE

ICE	P5-11	L6	L VALVE OPEN	OFF 0 vdc	LEFT WING VALVE IS CLOSED
				DIM 16vdc	LEFT WING VALVE IS OPEN
				BRIGHT 24vdc	LEFT WING VALVE IN TRANSIT
					OR VALVE AND SWITCH DISAGREE

ICE	P5-11	L4	R VALVE OPEN	OFF 0 vdc	RIGHT WING VALVE IS CLOSED
				DIM 16vdc	RIGHT WING VALVE IS OPEN
				BRIGHT 24vdc	RIGHT WING VALVE IN TRANSIT
					OR VALVE AND SWITCH DISAGREE

ICE	P5-11	L1	COWL VALVE OPEN	OFF 0 vdc	ENGINE 1 COWL VALVE CLOSED
				DIM 16vdc	ENGINE 1 COWL VALVE OPEN
				BRIGHT 24vdc	ENGINE 1 COWL VALVE IN TRANSIT
					OR VALVE AND SWITCH DISAGREE

ICE	P5-11	L2	COWL VALVE OPEN	OFF 0 vdc	ENGINE 2 COWL VALVE CLOSED
				DIM 16vdc	ENGINE 2 COWL VALVE OPEN
				BRIGHT 24vdc	ENGINE 2 COWL VALVE IN TRANSIT
					OR VALVE AND SWITCH DISAGREE

Simulator Solution:

A 12V Zener diode could be used to provide the reduction in Brightness for the Dim mode. This 12v zener diode could be wired to terminal number two (2) of a Korry 318 Chromalux® indicator "Circuit type 1" in series with a single pole switch to ground. A second switch could be wired in parallel with the 12v zener diode, and when it is closed the Bright mode (28V) would result.

Logic Table for Korry Indicator legend "VALVE CLOSED"
VALVE POSITION	12V Zener Switch 1 (S1)	Switch 2 (S2)	ILLUMINATION
OPEN	OPEN	OPEN	OFF
TRANSIT	OPEN OR CLOSED See Note 1	CLOSED	BRIGHT
CLOSED	CLOSED	OPEN	DIM
Note 1: For more realistic operation close S1 and S2 for BRIGHT, then open S2 for DIM, or both S1, S2 for OFF

Logic Table for Korry Indicator legend "VALVE OPEN"
VALVE POSITION	12V Zener Switch 1	Switch 2	ILLUMINATION
CLOSED	OPEN	OPEN	OFF
TRANSIT	OPEN OR CLOSED See Note 1	CLOSED	BRIGHT
OPEN	CLOSED	OPEN	DIM
Note 1: For more realistic operation close S1 and S2 for BRIGHT, then open S2 for DIM, or both S1, S2 for OFF

Page last updated on August 16, 2002
Copyright © 2002, 2001 David C. Allen