4
Considerations
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. *
z
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).
Cable
Requirements
Different cables are required for various devices.
Caution
Restrict cable length to less than 500’ (150m) for RS485 2wire or 4wire
devices and 50’ (15m) for RS232 devices to avoid communications
problems.
The COM light on the front of the MT-600 will turn on with each
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
2.3.1 Connector COM1 [RS232]
Pin Designations
COM1 [RS-232]
Pin assignment of the 9 Pin, Male, SUB-D, COM1 [RS-232] Port.
Pin# Symbol Function
1
DCD
Data Carrier Detect
2 RxD Received
Data
3 TxD Transmitted
Data
4 DTR Data
Terminal
Ready
5 GND Signal
Ground
6
DSR
Data Set Ready
7
RTS
Ready to send output
8
CTS
Clear to send input
9 RI
Ring
Indicator
