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DANGERS
When Designing your LogiTouch System:
- Be sure to design your LogiTouch control system so that in the event of a main
power supply failure or a LogiTouch accident, this system’s overall safety integ-
rity will be maintained. If this is not done, incorrect output signals or a LogiTouch
malfunction may cause an accident.
(1) Interlock circuits, etc. designed to interrupt or oppose normal machine move-
ment (i.e. Emergency Stop, General Protection, forward and reverse rotation,
etc.), as well as those designed to prevent machine damage (i.e. for upper,
lower and traverse movement limit positioning, etc.) should all be designed to
be located outside of the LogiTouch.
(2) Whenever the LogiTouch generates a “Watchdog Timer Error”, LogiTouch
operation will halt. Also, when an error occurs in Input/Output control areas
that the LogiTouch cannot detect, it is possible for unexpected equipment
operation to occur there. As a result, to prevent unsafe or unexpected equip-
ment operation, a “Failsafe Circuit” should be created which is completely
external to the LogiTouch.
(3) If an external unit’s relay or transistor malfunctions, causing an output (coil)
to remain either ON or OFF, a major accident can occur. To prevent this, be
sure to set up external watchdog circuits that will monitor vital output signals.
- Be sure to design a circuit that will supply power to the LogiTouch’s I/O unit(s)
before starting up the LogiTouch. If the LogiTouch’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 to occur.
- Be sure to design a program that will ensure the safety of your system in, in the
event of a LogiTouch display or control unit malfunction, or in the event of either
a data transmission error or power failure between the LogiTouch and any con-
nected unit(s). These types of problems can lead to an incorrect output (signal) or
malfunction, which could thereby cause an accident to occur.
- Do not create touch panel switches which could possibly endanger the safety of
humans or equipment. This is due to the possibility of a malfunction in the
LogiTouch or its cable(s), causing the output of a signal that could result in a
major accident. All of a system’s major, safety-related switches should be desig-
nated to be operated separately from the LogiTouch.
- Be sure to design your system so that equipment will not malfunction due to a
communication fault between the LogiTouch and its host controller. This is to
prevent any possibility of bodily injury or material damage.
- Do not use the LogiTouch with aircraft control devices or medical life support
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 LogiTouch with transportation vehicles (trains, cars and ships),
disaster and crime prevention devices, various types of safety equipment, non-
life support related medical devices, etc. be sure to use redundant and/or failsafe
system designs ensure the proper degree of reliability and safety.
