11
Programming Considerations
To conform with ICS Safety Recommendations, checks should be placed in the
controller to ensure that all writable registers that control critical parts of plant or
machinery have limit checks built into the program, with an out-of-limit safe shut
down procedure to ensure safety of personnel.
ICS 3-304.81 Safety Recommendations:
Consideration should be given to the use of an emergency stop function, which is
independent of the programmable controller.
Where the operator is exposed to the machinery, such as in loading or unloading a
machine tool, or where the machine cycles automatically, consideration should be
given to the use of an electromechanical override or other redundant means,
independent of the programmable controller, for starting and interrupting the cycle.
If provision is required for changing programs while the equipment is in operation,
consideration should be given to the use of locks or other means of assuring that only
authorized personnel can make such changes.
These recommendations are intended as safeguards against the failure of critical
components and the effects of such failures or the inadvertent errors that might be
introduced if programs are changed while the equipment is in operation. *
The ICS 3-304.81 Safety Recommendations are reproduced by permission of the
National Electrical Manufacturers Association from NEMA ICS 3-304
2.3 Communications Connections
The ports as you look at the back of the case, are the ports for connecting to a
PLC or some external device (Controller Connectors).
2.3.1 Connecter COM 1 [RS232]
Cable
Requirements
Different cables are required for various devices.
Caution
Restrict cable length to less than 500’ (150m) for
RS485/422 devices and 50’ (15m) for RS232
devices to avoid communications problems.
The COM light on the front of the NP-600S will turn
on with each communication.
Shielded cable must be used for long lengths or cables
