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SECTION 5 - MICROBOARD 031-03630-001
FORM 160.54-M1
ISSUE DATE: 10/25/2019
JOHNSON CONTROLS
JCI COMPANY CONFIDENTIAL
5
During the boot-up, the program in the FeRAM reads
wire jumpers PID0 through PID3 on the Display In-
terface Board to determine the manufacturer of the
display. Each display manufacturer requires a slightly
different control. The program in the FeRAM config-
ures the microboard for correct operation for the actual
display installed.
Different display manufacturers require different sup-
ply and control voltages for their displays and back-
lights. Program Jumpers JP2 through JP5 and JP7 and
JP8 must be configured to provide the required supply
and control voltages to the display and backlight control.
SECTION 5 - MICROBOARD 031-03630-001
lists the
required program jumper configuration for each display.
Also, a label attached to the display mounting plate lists
the required program jumper configuration for that dis-
play. The position of program jumper JP2 determines
whether the supply voltage is +5 VDC or +3.3 VDC.
The microboard controls the Display Backlight via J6.
The Display Backlight is the light source for the dis-
play. The Backlight Inverter Board (FL Backlight Dis-
plays) provides a high voltage AC power source for the
lamp. It converts low voltage DC via J6-1 (+12 VDC
or +5 VDC, depending on position of Program Jump-
er JP5) to high voltage AC (500 to 1500 VAC). This
high voltage AC is applied to the lamp to cause it to
illuminate. The Backlight is turned ON and OFF with
the “Backlight Enable” signal (J6-5). The position of
Program Jumper JP4 determines whether this is a +12
VDC or +5 VDC signal. In some displays, the backlight
turns ON when this signal transitions from low to high;
others turn OFF when it transitions from high to low.
The position of Program Jumper JP3 determines the
transition that will occur when the microboard outputs
the Backlight Enable signal. JP3 must be positioned
according to the display manufacturer’s requirement.
The microboard controls the backlight brightness via
the Lamp Dimmer circuit output at J6-7. In order to
extend the life of flourescent Backlight lamps, the
brightness is driven to 50% after 10 minutes of Key-
pad inactivity. At this brightness level, the graphics are
still visible. When Keypad activity is detected (a key is
pressed), the lamp is driven back to full (100%) bright-
ness. Some display manufacturers require a variable
voltage to vary the brightness; others require a variable
resistance. Program Jumpers JP7 and JP8 must be con-
figured to enable the appropriate technique. The Lamp
Dimmer is an integrated circuit that is the electrical
equivalent of a 10K ohm potentiometer
with 100 positions or steps (See
). The Lamp Dimmer controls the position of the
potentiometer. The Lamp Dimmer varies the bright-
ness of the backlight by applying a variable voltage (0
to 5.0 VDC) or a variable resistance (0 to 10K ohms)
to the Backlight Inverter Board (If applicable). If Pro-
gram Jumpers JP7 and JP8 are installed, the Lamp
Dimmer output is a variable voltage; if both are re-
moved, the output is a variable resistance. The Lamp
Dimmer outputs “Brightness Control Wiper” (J6-7) to
the Backlight Inverter Board. If configured for variable
voltage output, the voltage between J6-7 and J6-8 can
be varied from 0 VDC (100% brightness) to 5.0 VDC
(0% brightness). If configured for variable resistance,
the resistance between J6-6 and J6-7 varies from 0
ohms (0% brightness) to 10K ohms (100% brightness).
See
SECTION 7 - LIQUID CRYSTAL DISPLAY
,
TION 8 - DISPLAY INTERFACE BOARD
TION 9 - DISPLAY BACKLIGHT INVERTER BOARD
of this manual for details of the display interface.
Remote Setpoints
Remote Leaving Chilled Liquid Temperature and Cur-
rent Limit setpoints can be input via the RS-232 E-Link
Gateway interface at J2 or directly to the microboard at
J22 (See
). The inputs at J22
are configured with Program Jumpers JP23 and JP24
to accept these inputs in either 0 to 10 VDC, 2 to 10
VDC, 0 to 20mA or 4 to 20mA form. See Program
Jumper configurations and
of this manual for details of the Remote
setpoints.