Johnson Controls Frick QUANTUM Series Maintenance Manual page 45

chain, these voltages and signals cannot continue through
to the next board. Whenever a plug is not to be inserted
onto a board, either for servicing, or if not all boards are
present because of the options that are present, then a
shunting plug (refer to the Replacement Parts list) must be
installed onto the open connector.
The Analog Board requires the +5 Vdc for logic, the
-12 Vdc for internal voltage reference, and +12 Vdc for
external sensors (plus or +) and the Return (common or
-). The communications signals (RX & TX) are required by
all boards.
LOGIC VOLTAGE (POWER) LED'S
Located on the Analog Board are two power LED's. The
fi rst of these is D1 LED (+5VDC), and will be illuminated as
long as the Control Power switch is ON, and the proper
voltage is present at Analog Board connector P3. The
power supply generates the +5 VDC voltage, and passes
it on through the Power-I/O harness. 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 with regard to
the Analog Board, the best way to actually determine
this is to read the voltage on a DVM (Digital Volt Meter.
This may be accomplished by locating the white power
/ communications connector on the board. Notice that
the Analog Board has only one of these connectors. The
associated power / communications harness plugs in to
it. Take the red (positive) probe of the DVM and carefully
insert the end into the +5V lead, and the black (negative)
probe end into the RET (Return or Common) lead, as
shown below:
+5V
RET
Set the DVM to read DC, and set the proper range. The
voltage reading must read a minimum of +4.98 Vdc. The
Power-I/O harness will have an associated voltage drop at
each board connection. As an example, if you are reading
the voltage at the fi rst I/O board in the daisy-chain, and
it reads 4.98 Vdc, you can be assured that the voltage at
the subsequent connections for the remaining boards will
be lower yet. The voltage will need to be corrected for
proper operation of the system.
The cause for a low voltage reading could be:
• The Remote panel power supply may need
adjustment (see the section on power supplies).
• The Power-I/O communications harness has a
problem (a new harness may be needed).
QUANTUM™ LX CONDENSER/VESSEL CONTROL PANEL
MAINTENANCE
• A problem may exist with one of the I/O boards
(Digital or Analog).
• If the power LED is not lighted, check the cable for
proper connectivity. Note: Each board provides
the necessary connections to feed all signals to
the following connectors. If the auxiliary Analog
or Digital Board is not present then a jumper
plug (Part # 640B0039H01) must be installed to
daisy-chain the signals.
The second power LED is D5 (+24Vdc). This +24Vdc
voltage is generated on the Analog Board from the +5Vdc
supply being fed from the Remote panel power supply. If
the +5Vdc is present as stated earlier, then this LED will
illuminate if the on-board +24Vdc supply is functioning
properly.
ACTIVE LED
The Analog Board has an Active LED indicator that blinks
when the board's software is running.
If the Active LED is not blinking, it could be an indication
that the internal program is not running. Try powering the
Remote panel off, then back on to see if the Active light
starts blinking. If not, a new board may be required.
ANALOG INPUTS
An Analog Input is the portion of the hardware that
allows devices such as temperature sensors and pressure
transducers, to interface with the Quantum™
software program within the Quantum™ is constantly
looking at these Input channels, via communications,
and based upon what the voltage or current level of
the channel is, will provide the necessary control for an
associated action.
Analog inputs arrive at the board on connectors P4
through P10. Each of these connectors can receive two
channels (for a total of twenty-four).
ANALOG OUTPUTS
An Analog Output is the portion of the hardware that the
Quantum™ uses to provide control. These outputs are
dedicated for a 4-20 mA signal and cannot be changed
through the software confi guration.
TROUBLESHOOTING THE ANALOG INPUTS AND
OUTPUTS
Some problems that may be encountered involve
troubleshooting the Analog inputs and outputs. The Analog
Board has twelve Analog I/O board connectors labeled
P4 through P10. The external Analog devices are wired
to a connector plug. Position 1 connects to the plus (+)
of the external device for channel 1, position 2 connects
to the signal (SIG) of the external device for channel 1
and position 3 connects to ground (GND) of the external
device for channel 1. Position 4 connects to the plus (+)
of the external device for channel 2, position 5 connects
to the signal (SIG) of the external device for channel 2
090.560-M (APRIL 13)
Page 45
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