Microboard (331-03478-Xxx); Power Supplies And Leds; Power Supply Test Points; Configuration Jumpers - York YVAA Installation, Operation & Maintenance Instructions Manual

SECTION 7 - OPERATION
UNIT WARNING: !! LOW BATTERY !!
CHECK SETPOINTS/PROGRAM/OPTIONS/TIME
If a low battery condition exists, all programmed
setpoints, program values, time, schedule, and history
buffers will have been lost. These values will all be
reset to their default values, which may not be the
desired operating values. Once a bad battery is
detected, the unit will be prevented from running un-
til the MANUAL OVERRIDE key is pressed. Once
the MANUAL OVERRIDE key is pressed, the anti
recycle timers will be set to the programmed default anti
recycle time to allow the operator sufficient time to
check setpoints, program values, and so on.
If a low battery is detected, it should be replaced as
soon as possible. The programmed values will all be
lost and the unit will be prevented from running on the
next power interruption.

MICROBOARD (331-03478-XXX)

The 331-03478-xxx microboard was developed as
a direct replacement for the 031-02478-xxx line of
microboards. No adapter harness is required when
replacing a 02478 with the new 03478. The 03478
uses the IPUII processor card and provides some new
features for the chillers that the 02478 did not have.
The 03478 program resides in flash memory instead
of EPROM. Program updates are accomplished by
loading the new program from an SD card inserted into
the SD card reader/writer. This same SD card reader/
writer also allows the user to datalog the operating
parameters to an SD card every 5 seconds. This infor-
mation is invaluable when troubleshooting unit and
system problems since it allows the service techni-
cian to view operating parameters prior to a unit fault.
Details on the new datalogging capability are explained
in the OPTIONS Key area of this manual. A Real Time
Clock/BRAM keeps time and setpoints during power
outages.
Refer
Figure 19 on page 105. to locate the follow-
ing ports of the 03478 microboard.

Power Supplies and LEDs

The 03478 has LEDs to indicate various states of op-
eration of the microboard.
STATUS – Flashes every ½ second to indicate that the
base board processor is running its program.
104
POWER – On solid indicates that the base board +12V
and +5V power supplies are operational.
TX1 – Red LED flashes when transmitting data out
Port 1 TB3 (Future native communications BAS port).
RX1 – Green LED flashes when receiving data in Port
1 TB3 (Future native communications BAS port).
TX2 – Red LED that flashes when transmitting data
out Port 2 (E-Link TB2 or printer TB1).
RX2 – Green LED that flashes when receiving data in
Port 2 (E-Link TB2 or printer TB1).
VSD_TX – Red LED that flashes when transmitting
data out Port 3 to the VSD Logic board.
VSD_RX – Green LED that flashes when receiving
data in Port 3 from the VSD Logic board.
24VAC power is applied to the 331-03478-xxx
microboard connector J12 and is then used to create the
various DC power sources required by the microboard
circuitry. If the chiller control is malfunctioning, the
power supply test points should be measured to deter-
mine the status of the microboard.

Power Supply Test Points

TP1 GND (Measure TP2, TP3, TP4 and TP5 in
reference to this Test Point).
TP2 +3.3V [3.2 to 3.4VDC] provides power to the
processors.
TP3 +5V [4.8 to 5.2VDC] power communication ports
2,3 and 4 and analog sensors.
TP4 +12V [11.64 to 12.36VDC] powers the display
and backlight and is regulated to become the +5V.
TP5 +15V [11.3 to 16.6VDC] powers the analog
outputs to the EEV valves.

Configuration Jumpers

The same configuration jumpers that existed on the
02478 are provided on the 03478.
JP4 Remote Temp Reset jumper position Pins 1 to 2
(left) = 4-20 mA, Pins 2 to 3 (right) = 0-10 VDC.
JP5 Remote Current Limit jumper position Pins 1 to 2
(left) = 4-20 mA, Pins 2 to 3 (right) = 0-10 VDC.
JP6 Remote Sound Limit jumper position (Pins 1 to 2
(left) = 4-20 mA, Pins 2 to 3 (right) = 0-10 VDC.
FORM 201.28-NM1.1
ISSUE DATE: 1/31/2018
JOHNSON CONTROLS