A-3
[DESIGN PRECAUTIONS]
DANGER
When controlling a running programmable controller (data modification) by
connecting a peripheral device to the CPU module or a PC to a special
function module, create an interlock circuit on sequence programs so that the
whole system functions safely all the time.
Also, before performing any other controls (e.g. program modification,
operating status change (status control)), read the manual carefully and
ensure the safety.
In these controls, especially the one from an external device to a
programmable controller in a remote location, some programmable controller
side problem may not be resolved immediately due to failure of data
communications.
To prevent this, create an interlock circuit on sequence programs and
establish corrective procedures for communication failure between the
external device and the programmable controller CPU.
When setting up the system, do not allow any empty slot on the base unit.
If any slot is left empty, be sure to use a blank cover (A1SG60) or a dummy
module (A1SG62) for it.
When using the extension base unit, A1S52B(S1), A1S55B(S1) or
A1S58B(S1), attach the included dustproof cover to the module in slot 0.
Otherwise, internal parts of the module may be flied in the short circuit test or
when an overcurrent or overvoltage is accidentally applied to external I/O
section.
CAUTION
Do not install the control lines or communication cables together with the
main circuit or power lines, or bring them close to each other.
Keep a distance of 100mm (3.94inch) or more between them.
Failure to do so may cause malfunctions due to noise.
If having read register R outside the allowable range with the MOV
instruction, the file register data will be FFFF
H
. Using this as it is may cause
malfunctions. Pay attention not to use any out-of-range file register when
designing sequence programs. For instruction details, refer to the
programming manual.
When an output module is used to control the lamp load, heater, solenoid
valve, etc., a large current (ten times larger than the normal one) may flow at
the time that the output status changes from OFF to ON. Take some
preventive measures such as replacing the output module with the one of a
suitable current rating.
