Functional Overview - Mitsubishi Electric MELSEC Q Series Programming Manual

1 OVERVIEW

1.1 Functional Overview

Motion controller has safety observation functions such as safety signal comparison,
speed monitoring function, safe speed monitor, shut-off function, standstill monitoring,
and safe brake control in addition to the general purpose Motion control functions.
Furthermore, for Motion CPUs that support safety communication function, a safety
communication compatible servo amplifier and safety encoder may be included in the
system.
All the safety of human lives and properties are not guaranteed by these functions.
Execute risk assessment by user and reduce the level of risk until the residual risk is
less than the tolerable risk.
• Safety signal comparison
A safety signal is input/output to/from PLC CPU and Motion CPU. The CPUs
compare the safety signals. The power will be shut off if error occurs.
• Speed monitoring function (SLS)
PLC CPU and Motion CPU monitor if the motor speed does not exceed the safety
speed. The power will be shut off if error occurs.
• Safe speed monitor (SSM)
SSM outputs the safety signal indicating the motor speed is safety speed or lower.
• Shut-off function (STO, SS1)
This function is composed of SS1 and STO. SS1 function initiates the motor
deceleration and initiates the STO function after an application specific time delay.
STO function shuts power to the motor.
• Standstill monitoring (SOS, SS2)
This function is composed of SOS and SS2. SS2 function initiates the motor
deceleration and initiates the STO function after an application specific time delay.
SOS function monitors if the motor stand still while power is being supplied.
• Safe brake control (SBC)
Two control signals for holding the motor by brake are output.
• Safety communication function
Communicates safety information with the servo amplifier by using the safety
communication function in a system compatible with safety communication.
Also checks the operation and status of safety observation functions in the servo
amplifier with the safety sequence program of the user.
Speed monitoring function and standstill monitoring can be performed using a safety
encoder.
(1) Correspondence table for function name of EN standards and safety observation
function in a Motion system.
Abbreviation
SLS
SSM
STO
SS1
SOS
SS2
SBC
QDS
Function name
IEC 61800-5-2
Safely-limited Speed
Safe Speed Monitor
Safe Torque Off
Safe Stop 1
Safe Operating Stop
Safe Stop 2
Safe Brake Control
1 - 3
Motion system
Speed monitoring function
Safe speed monitor
Shut-off function
Standstill monitoring
Safe brake control