Frick QUANTUM LX Control Panel - Page 38

QUANTUM
™
LX EVAPORATOR CONTROL PANEL
MAINTENANCE
090.610-M (MAY 2016)
Page 38
REPLACING A DEFECTIVE ANALOG BOARD
The procedure to replace an Analog board is outlined
below:
1. Ensure that all channel conguration
information for the board being replaced has
been written down.
2. Shut off control power.
3. Unplug all connectors from the board.
4. Remove the old board from the unit and
remove the new board from its packing and
place both on an anti-static surface.
5. Check that all jumpers, dipswitches and
components are properly setup on the new
board using the old board as a reference (refer
to the Analog Settings tables near the end of
this section).
6. Install the modied replacement board in the
panel.
7. Plug all connectors back in.
8. Turn on control power.
9. After the panel has rebooted, access the
Analog Board Conguration Setup screen, and
re-enter the correct channel conguration.
The default setup of the new board will be
loaded to the processor. It is imperative that
the channel conguration screen be accessed
to ensure that the channels are congured
properly for the application.
After replacing or installing an Analog Board and
powering on the control panel, select User Level 1
or higher, then select the Setpoints Menu, then the
Communications Menu. On the Communications Screen
is a button labeled as [Redetect I/O Comms]. Clicking
on the [Redetect I/O Comms] button will cause the
controller to examine the internal I/O communications
of the panel, and initialize all connected boards If
a board has been removed, a communication error
shutdown will be issued until this key is selected. The
About screen will show what was detected.
to ground (GND) of the external device for channel 2,
as shown below:
GND
Channel 2 +
Channel 1
+
Channel 1
Signal
Channel 2
Signal
GND
Each input channel is congurable through the
operating software. There are twenty-four analog
input channels that can be selected for 4-20 mA,
0-5 Vdc, ICTD, or RTD. Besides properly setting the
software conguration, each channel is setup through
software calibration for the proper transducer type and
range, and each transducer must be calibrated through
the appropriate sensor calibration screen. Improper
setup of either the hardware or software will result in
incorrect operation or range.
The most common fault associated with the improper
reading of the analog channels other than hardware or
software setup problems fall into one of the following
categories:
• Sensor fault
• Wiring problem
• Improper grounding of system.
An open wire, shorted wire, or faulty sensor will usually
give a reading at either the minimum or maximum end
of the range scale. An erratic reading or a reading
that seems to oat up and down is usually indicative
of a grounding problem. When a single transducer or
cable is shorted to earth (or system) ground, this can
show up as a whole assortment of problem channels.
The easiest way to nd a short to earth problem is to
disconnect all the sensor plugs and ohm out each plug
screw terminal to earth for open (innite) impedance.
All sensors should read open to earth. The third pin on
pressure sensors is ground.