Sterling XXX10-80 User Manual

10-Pump, 80-Station Controller 

Chapter 2:  Functional Description 

11 

•  Identify and locate specific safety devices. 
•  Understand the proper use of the safety devices provided. 
•  Describe the function of the safety device. 

Safety Circuit Standards 
Safety circuits used in industrial systems protect the operator and maintenance personnel 
from dangerous energy. They also provide a means of locking out or isolating the energy for 
servicing equipment. 

Various agencies have contributed to the establishment of safety standards that apply to the 
design and manufacture of automated equipment. The Occupational Safety and Health 
Administration (OSHA) and the Joint Industrial council (JIC) are just a few of the 
organizations that have joined with the plastics industry to develop safety standards. 

Every effort has been made to incorporate these standards into the design of the controller; 
however, it is the responsibility of the personnel operating and maintaining the equipment to 
familiarize themselves with the safety procedures and the proper use of any safety devices. 

Fail Safe Operation 
If a safety device or circuit should fail, the design must be such that the failure causes a 
“Safe” condition. As an example, a safety switch must be a normally open switch. The switch 
must be held closed with the device it is to protect. If the switch fails, it will go to the open 
condition, tripping out the safety circuit. 

At no time should the safety device fail and allow the operation to continue for example, if a 
safety switch is guarding a motor, and the safety switch fails, the motor should not be able to 
run. 

Safety Device Lock-Outs 
Some safety devices disconnect electrical energy from a circuit. The safety devices that are 
used in this Controller are primarily concerned with electrical power disconnection.