Proface LT4300M - 5.7 Modular HMI + Control" - Manual (Page 112)

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For additional information, refer to NEMA ICS 1.1 (latest edition), "Safety Guidelines for the
Application, Installation, and Maintenance of Solid State Control" and to NEMA ICS 7.1 (latest
edition), "Safety Standards for Construction and Guide for Selection, Installation and Operation of
Adjustable-Speed Drive Systems" or their equivalent governing your particular location.
Handling the LCD
The following characteristics are specific to the LCD and are considered normal behavior:

LCD screen may show unevenness in the brightness of certain images or may appear different
when seen from outside the specified viewing angle. Extended shadows, or cross-talk, may also
appear on the sides of screen images.
 LCD screen pixels may contain black and white-colored spots and color display may seem to
have changed over time.
 When the same image is displayed on the screen for a long period, an after-image may appear
when the image is changed. If this happens, turn off the unit, wait 10 seconds, and then restart it.
NOTE: Do not display the same image for a long time. Change the screen image periodically.
WARNING
LOSS OF CONTROL
 Consider the potential failure modes of control paths in the machine control system design,
such as:
 The possibility of backlight failure,
 Unanticipated link transmission delays or failures,
 The operator being unable to control the machine,

The operator making errors in the control of the machine.
 Design outside the LT operations such as emergency stop, safety circuits, interlocks that
operate with opposing actions such as clockwise/counterclockwise rotation, and circuits that
prevent machine damage with positioning limits on top, bottom, and movement.
 For important operations handled by switches, design your system to use a separate hardware
device. This is to reduce the occurrence of incorrect outputs or malfunctions.
 Observe all accident prevention regulations and local safety guidelines.
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 Test individually and thoroughly each implementation of the equipment for correct operation
before service.
Failure to follow these instructions can result in death, serious injury, or equipment
damage.
WARNING
UNINTENDED EQUIPMENT OPERATION
 Do not use the LT as a control unit for system critical operations such as start/stop or output
control of motors.
 Do not use the LT as the only warning device for critical alarms such as device overheat or
device over-current.
Failure to follow these instructions can result in death, serious injury, or equipment
damage.