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6 FUNCTIONAL SAFETY
6.4 Safety sub-function
SDI function
Outline
This function monitors whether the servo motor travels in the specified direction. If the servo motor travels in a direction
different from the specified direction, the STO function will be activated.
Operation sequence
The SDI function is activated by turning off SDIPC (SDIP command) or SDINC (SDIN command). When SDIPC (SDIP
command) is turned off, the function monitors the address increasing direction. When SDINC (SDIN command) is turned off,
the function monitors the address decreasing direction. The function starts monitoring when either the time set in [Pr. PSA27
SDI positive direction monitor delay time] or [Pr. PSA28 SDI negative direction monitor delay time] has elapsed after SDIPC
(SDIP command) or SDINC (SDIN command) is turned off. During monitoring, the function monitors whether the speed is
within [Pr. PSA04 Safety sub-function - Stop speed] for the specified monitoring direction. Monitoring ends by turning on
SDIPC (SDIP command) or SDINC (SDIN command).
The SDI direction monitor delay time can be specified individually for the address increasing direction and for the address
decreasing direction.
The operation sequence by SDIPC (SDIP command) is shown below. The function monitors the address increasing direction.
SDI command
Monitoring direction
Applied SDI direction monitor delay time
SDIP command
Address increasing direction
[Pr. PSA27 SDI positive direction monitor delay
time]
SDIN command
Address decreasing direction
[Pr. PSA28 SDI negative direction monitor delay
time]
0 r/min
(mm/s)
SDI positive direction
monitor delay time
An alarm will occur if the stop
speed in the address increasing
direction is exceeded.
Direction monitoring
Feedback
Stop speed
Servo motor speed
Stop speed
Command
ON (disabled)
SDIPC (SDIP command)
OFF (enabled)
ON (disabled)
SDIPS (SDIP output)
OFF (enabled)
ON (disabled)
SDINC (SDIN command)
OFF (enabled)
ON (disabled)
SDINS (SDIN output)
OFF (enabled)