Banner EZ-SCREEN­ Safety Light Curtain Systems - Manual (Page 49)

page 49
Banner Engineering Corp. • Minneapolis, MN U.S.A.
www.bannerengineering.com • Tel: 763.544.3164
Troubleshooting and Maintenance
EZ-SCREEN Grid
Instruction Manual
5.2 Electrical and Optical Noise
The EZ-SCREEN System is designed and manufactured to be highly resistant to
electrical and optical noise and to operate reliably in industrial settings. However,
serious electrical and/or optical noise may cause a random trip or latch condition.
In very extreme electrical noise cases, a lockout is possible. In order to minimize
the effects of transitory noise, the EZ-SCREEN System will respond to noise only
if the noise is detected on multiple consecutive scans.
If random nuisance trips occur, check the following:
• Poor connection between the sensor and earth ground;
• Optical interference from adjacent light grids or other photoelectrics; or
• Sensor input or output wires routed too close to “noisy” wiring.
Checking for sources of electrical noise: It is very important that the light grid
sensors have a good earth ground. Without this, the system can act like an
antenna and random trips and lockouts can occur.
All EZ-SCREEN System wiring is low voltage; running these wires alongside
power wires, motor/servo wires, or other high-voltage wiring, can inject noise
into the EZ-SCREEN system. It is good wiring practice (and may be required by
code) to isolate EZ-SCREEN System wires from high-voltage wires.
The Banner BT-1 Beam Tracker is a very good tool for detecting electrical noise.
It can be used to detect electrical transient spikes and surges. Cover the lens of
the BT-1 with electrical tape to block optical light from getting into the receiver
lens. Press the “RCV” button on the BT-1 and position the Beam Tracker on the
wires going to the EZ-SCREEN or any other nearby wires. Noise caused by the
switching of inductive loads should be addressed by installing proper transient
suppression across the load.
Checking for sources of optical noise:
Turn off the emitter, completely block the emitter beams, or open the Test input,
then use a Banner BT-1 Beam Tracker to check for light at the receiver. Press the
“RCV” button on the BT-1 and move it across the full length of the receiver’s
sensing window. If the BT-1’s indicator lights, check for light from other sources
(other safety light screens, grids or points, or standard photoelectric sensors) by
“tracking down” the emitted light from them.
WARNING . . .
Shut Down Machinery
before Servicing
The machinery connected to the
EZ-SCREEN Grid System must not
be operating at any time during
this procedure. Some servicing
procedures may involve working
close to the hazardous areas of the
guarded machine.
Serious bodily injury or death
could result.
!
WARNING . . .
Power Failures and
Lockouts
A lockout is a definite indication of
a problem and should be
investigated at once, by a
Qualified Person.
Attempts to continue to operate
machinery by bypassing the EZ-
SCREEN Grid System are
dangerous and could result in
serious bodily injury or death.
!
CAUTION . . .
Electrical Danger
Exercise care whenever
troubleshooting, repairing, or
modifying the EZ-SCREEN System
and/or the machine control
system. Always disconnect all
power from the EZ-SCREEN Grid
System and the guarded machine
before making any wire
connections or before replacing
any component.
Electrical connections or repairs
should be done only by a Qualified
Person (see Safety Glossary).
!