Proface LT3300 - 5.7 All-in-One HMI" - Manual (Page 4)

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Design a circuit that will supply power to the LT unit’s I/O before starting up the LT. If the LT unit’s internal
program enters RUN mode prior to the I/O unit’s load control power turning ON, an incorrect output
(signal) or malfunction could cause an accident.
Design a user program that ensures the safety of the user’s system, in the event of a LT display or control
error, or either a data transmission error or power failure between the LT and a connected unit. These
types of problems can lead to an incorrect output (signal) or malfunction, resulting in an accident.
Do not make switches using the switches on the touch panels which may cause operator injury and
machine damage. An output may remain either ON or OFF and a major accident can occur. To prevent
this, set up circuits such as limiters that will monitor vital output signals. Design switches for important
operations to be performed by separate devices. An incorrect output or malfunction can occur and thereby
cause an accident.
Do not create LT touch panel switches to control machine safety operations, such as an emergency stop
switch. Install these switches as separate hardware switches, otherwise severe bodily injury or equipment
damage can occur.
When using the LT with transportation vehicles (trains, cars, and ships), disaster and crime prevention
devices, various types of safety equipment, and medical devices that are not life-support related, use
redundant and/or failsafe system designs to ensure proper reliability and safety.
Do not use the LT as a warning device for critical alarms that can cause serious operator injury, machine
damage or can halt system operation. Critical alarm indicators and their control/activator units must be
designed using stand-alone hardware and/or mechanical interlocks.
Do not use the LT with aircraft control devices, aerospace equipment, central trunk data transmission
(communication) devices, nuclear power control devices, or medical life support equipment, due to these
devices’ inherent requirements of extremely high levels of safety and reliability.
When using the LT with transportation vehicles (trains, cars, and ships), disaster and crime prevention
devices, various types of safety equipment, and medical devices that are not life-support related, use
redundant and/or failsafe system designs to ensure proper reliability and safety.
After the LT unit’s backlight burns out the touch panel is still active, unlike the LT unit’s “Standby Mode”. If
the operator fails to notice that the backlight is burned out and touches the panel, a potentially dangerous
machine operation error can occur. Therefore, do not create LT unit touch panel switches that may cause
injury and/or equipment damage. If your LT unit’s backlight suddenly turns OFF, use the following steps to
determine if the backlight is actually burned out.
1) If the LT unit’s “Backlight Control” is not set and the screen has gone blank, your backlight is burned
out.
2) If the LT unit’s “Backlight Control” is set to Standby Mode and the screen has gone blank, and touching
the screen or performing another input operation does not cause the display to reappear, your backlight
is burned out.