QUANTUM™ HD UNITY SYSTEM CONTROLLER
MAINTENANCE
090.670-M (APR 2020)
Page 42
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The wrong analog output signals being sent from the
board.
Connections to the Quantum™
The analog and digital boards are connected to their re-
spective Q5 and Q6 processor boards using RS-485 serial
communications. The following is a list of the number of
potential analog boards for each section of the control:
• Condenser - 1
• Vessel - 2
• Engine Room - 1
• Evaporator - 10
The Analog Board requires the +24 VDC. The +24 VDC is
broken down on the analog as needed.
Logic Voltage (Power) LEDs
Located on the Analog Board is a power LED. It is desig-
nated as D65, and will be illuminated as long as the Con-
trol Power switch is ON, and voltage is present at Analog
Board connector P3. The power supply generates the +24
VDC voltage, and passes it on through the Power-I/O har-
ness. This LED does not indicate however that the proper
voltage is necessarily present at the board, only that the
voltage is enough to energize the voltage sensing circuitry.
If a voltage related problem is suspected, use a calibrated
meter to read the +24 VDC at the P3 connector. Insert the
red (positive) probe in alongside the gray +24 VDC lead
and the black (negative probe into the RET return or com-
mon) lead as shown below.
+24VDC
RET
Set the DVM to read DC, and set the proper range. The
voltage reading must be in the range of 24.2 to 24.6 at
each analog board connected to the 24 VDC power supply.
Active LED
The Analog Board has an Active LED indicator that pulses
when the board’s software is running. The Active LED is
designated as D64. It is located near the center of the
analog board.
If the Active LED is not pulsing at a rate of approximately 1
time per second, it could be an indication that the internal
program is not running. Cycling power to the board may
correct this issue. Rather than powering down the entire
controller, carefully unplug the P3 connector at the af-
fected board for around 3 s to 5 s and plug back in. If the
Active light does not start pulsing, the board will need to
be replaced.
Analog Board
Preface
The Quantum™ HD Unity System Controller is capable
of reading external analog devices, such as temperature
probes and pressure sensors. It uses these input signals
for the purpose of monitoring and control. As an example,
if an external temperature sensor begins to read a higher
than expected temperature in some area, the control-
ler would sense this change, and provide the necessary
corrective action, or issue a warning or shutdown. Unlike
a digital signal, which is typically an on or off state, an
analog signal is infinite within a range (low to high).
Signals are received (and sent) through the analog board.
The analog devices are wired directly to the board, and
the on-board software/hardware converts the electri-
cal signals received from these devices into counts. The
counts are then communicated to the Q5 and Q6 proces-
sor boards, and monitored by the control software.
This board features twenty-four input channels, and
eight output channels. The board channels are configured
through software, rather than using physical jumpers. A
more detailed description of the operation of this board is
provided in the sections that follow.
The Analog Board is a microprocessor board and is
programmed to control analog outputs, or accept analog
inputs, from external electrical devices. Each board has
the capability of 24 independent input channels. These I/O
channels are dedicated through the software and external
wiring, as to the function of each channel.
Communications LEDs
The Q5 and Q6 processor boards are in constant com-
munication with the Analog (and Digital) Board(s). On each
Analog and Digital board there are a pair of LEDs that are
labeled as RX and TX. These letters represent receive (RX)
and Transmit (TX). These LEDs flash rapidly during normal
operation. This indicates that the Q5 and Q6 processor
boards, and the respective I/O boards are properly com-
municating with each other.
• See
Jumper And Dipswitch Settings
later in this sec-
tion. This section contains the dipswitch settings
for addressing the Analog I/O Boards. When these
switches are properly set, the Quantum™ HD Unity is
able to serially communicate with each I/O board and
provide control signals and data exchange. If these
switches are not properly set, the result can be one of
the following:
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Lost or failed communications
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The wrong analog input signals being received
Figure 28: Analog board
Figure 29: Return lead
