QUANTUM
™
LX EVAPORATOR CONTROL PANEL
MAINTENANCE
090.610-M (MAY 2016)
Page 49
SECTION 8
TROUBLESHOOTING
TROUBLESHOOTING A PROBLEM THAT APPEARS
UNEXPLAINABLE
When there is a problem that makes no sense due to
unexplainable things happening, check the following:
• Is the panel powered by an isolating power source
such as a control transformer?
• Is the panel powered from a lighting or utility
panel?
• Has the unit ever worked properly?
• If the unit used to work properly, try to determine
when the problem rst showed up.
• It is important to know if the problem occurs
randomly, frequently, or all the time.
• Check what the temperature is at the unit location.
Is it very hot or very cold?
• Make sure that a motor is not blowing exhaust air
on the control panel.
• If it just started to act up, then check if there was
recently a severe lightning storm, re, ood, or a
plant accident. If any of the following conditions
are possible, then check for it:
• Has any water, refrigerant, or oil leaked into the
panel or conduit?
• If it just started to act up, then check if anything
was recently changed in the system (i.e. software
or hardware.)
• If it just started to act up, then check if any service
was recently done to the unit or its electrical
system?
• If the Quantum™ is unexplainably shutting down,
try disconnecting the communications cable to see
if the problem goes away.
• Check if the communications cable shields are
tied to machine ground at only one location. For
a PLC or Opto22 based system, the shield should
normally be tied only at the PLC or Opto22 panel.
• Check that you are using the Frick
®
recommended
communications cable. See manual to match
proper cable with type of communications (i.e.,
RS-422, RS-232, RS-485, or some other type of
factory communication bus system.)
• If this is an older plant, has the plant wiring been
brought up to code?
• Is power wiring mixed with control wiring?
• Is power wiring mixed with sensor wiring?
• Is power wiring mixed with communications
wiring?
• Ensure that pressure transducers are properly
grounded. The two types of transducers you
may have are as follows: an older type has an 8
to 10 inch 3-conductor pigtail coming out of the
transducer. This type will have the attaching cable’s
shield cut off and insulated at the transducer end.
The shield is then tied to a panel ground terminal
in the panel. The newer type has the cable as an
integral part of the housing and has the shield
crimped to the case at the transducer end. This
type of transducer has the cable’s shield cut off
and insulated in the control panel.
• Ensure that temperature transducers are properly
grounded. The temperature probes usually have
two short wires coming out of the sensor, and are
tied to a shielded cable at the thermal well head.
The shield is insulated at the temperature probe
and grounded at the panel end.
• Check if one of the temperature probes has a
signal wire shorted to machine ground. To do this,
rst pull the orange plug from the appropriate
channel of the Analog board and then use a DVM
and check each white wire to machine ground and
each black wire to machine ground.
• Check that all inductive loads (i.e. Coils, Solenoids,
or Relays, etc.) connected to the I/O output
modules have surge suppressers across them,
preferably at the devices and not at the panel end.
• Make sure that you have a continuous ground back
to the power source. The ground connection must
be aluminum or copper. A conduit ground will not
work.
• Ensure that there is no AC wiring lying next to any
printed circuit boards.
• Unexplainable unit failures are usually indicative
of noise due to wiring problems (i.e. incorrect
earth grounds, mixed power and control wiring,
unsuppressed coils, etc)
• If the unit is unexplainably shutting down, check if
the machine shares power with something else.
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