4
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 Connector COM1 [RS232], COM2 [RS232]
Cable
Requirements
Caution
Different cables are required for various devices.
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 MMI8000 turns on with each Ethernet communication.
Shielded cable must be used for long lengths or cables run in an electrically noisy environment.
Do not run cables next to AC power lines or near sources of electrical noise.
Be sure that the cable ends have been inserted all of the way into mating connectors and are
secure
Pin assignment of the 9 Pin, Male, SUB-D, COM1 [RS-232] and COM2
[RS-232] Port.
Pin #
Symbol
COM1 [RS232]
COM2 [RS232]
1
Not used
2
RxD
Received Data
3
TxD
Transmitted Data
4
TxD
Transmitted Data
5
GND
Signal Ground
Signal Ground
6
RxD
Received Data
7
RTS
Ready to send output
8
CTS
Clear to send input
9
Not used
Pin
Designations
COM1 [RS-232]
COM2 [RS-232
]
