Safety Signal Comparison; Speed Monitoring Function (Sls) - Mitsubishi Electric MELSEC Q Series Programming Manual

1 OVERVIEW

1.4.1 Safety signal comparison

1.4.2 Speed monitoring function (SLS)

(1) Make sure that the mounting location of the safety signal module, MT Developer2
number head device, and GX Works2/GX Developer I/O assignments are
correctly set.
(2) When a signal error occurs, make sure that safety is secured within the signal
mismatch permissible time that is set by a parameter.
(3) Even when a signal error occurs, the servo motor does not stop automatically.
Give a (forced) stop command and execute a forced stop processing.
(4) Make sure that the ladder name to be written to a PLC CPU is not the same as
that of sequence programs for safety observation.
(5) Make sure that the safety signal is properly input via two different paths.
(6) Make sure that the screws will not get loose after fixing the connector on the
safety signal module.
(7) Make sure that all the modules are firmly inserted into the main base unit or
extension base unit.
(8) Scan time processing must be within 100ms so that PLC CPU performs the
comparison function within a certain process time. Make sure that the program
contents can be handled less than 100ms. If the scan time is 100ms or longer,
PLC CPU should be added for safety to distribute the load of the safety process.
(1) Under the condition that the failure rate of the additional pulse encoder
components does not exceed 195FIT/395FIT the resulting PFD/PFH will be less
than 195FIT/395FIT. (See below diagram.)
Common Comp.
Common
Additional Pulse
(PSU)
Encoder Comp.
(2) Avoid the continuous use (about 8 hours) of the same Speed Monitor parameter
block to prevent the accumulation of errors.
Q17 DSCPU
Encoder MR-J4- B
PLG
1 - 10
Q173DSXY
Motion
Motion
I/O
QnUDHCPU
/Q3nDB
PLC
PLC
I/O
ch A
ch B