Mitsubishi Electric MELSEC iQ-R Series Safety Function Block Reference page 71

WARNING
• Use safety data for connecting the variable whose data type is "Bit*" to input-output circuits.
• Safe input must be connected to i_bMutingSw_11/12/21/22 depending on the safety requirements. Input appropriate signals depending on the safety
requirements of the application.
• A short circuit in the muting sensor signals or a functional application error to supply these signals are not detected by this FB but interpreted as incorrect
muting sequence. However, this condition should not lead to unwanted muting. The user should take care to include this in his risk analysis.
• A safety program is executed as a fixed scan execution type program.
• A safety program is executed at a fixed cycle according to a set safety cycle time. The safety FB that monitors the time must meet the following requirements.
⋅ The timeout processing may be delayed by the safety cycle time by executing the safety program. Set the safety cycle time so the delay by the safety
cycle time does not pose a hazard.
⋅ If the program is executed exceeding the safety cycle processing time, the timeout may be delayed. Ensure that an abnormality does not occur during
operation.
FB details
Muting is the intended suppression of the safety function. This is required, e.g., when transporting a workpiece into the danger
zone without causing the machine to stop. Muting is triggered by muting sensors. The use of two or four muting sensors and
correct integration into the production sequence must ensure that no persons enter the danger zone while the light curtain is
muted. Muting sensors can be proximity switches, photoelectric barriers, limit switches, etc. which do not have to be failsafe.
Active muting mode must be indicated by indicator lights (the muting lamp).
There are sequential and parallel muting procedures. In this FB, parallel muting with four muting sensors is used. The FB can
be used in both directions, forward and backward. The muting should be enabled with the i_bMutingEnable signal by the
process control when there is no manipulation in the danger zone.
The FB input parameters include the signals of the four muting sensors (i_bMutingSw_11 to i_bMutingSw_22), the OSSD
signal (i_bS_AOPD_In) from the "active opto-electronic protective device", as well as three parameterizable times
(i_dDiscTime11_12, i_dDiscTime21_22, and i_dMaxMutingTime). For forward direction, from the time when both
i_bMutingSw_11/12 are set to ON until when both i_bMutingSw_21/22 are set to ON and one of them turns OFF, muting is
active and o_bS_AOPD_Out is set to ON, although i_bS_AOPD_In is OFF. For backward direction, muting is active from the
time when both i_bMutingSw_21/22 are set to ON until when both i_bMutingSw_11/12 are set to ON and one of them turns
OFF.
■ Example for M+SF_MUTEP_R in forward direction with four sensors
Figure
MS_11 Transmitter MS_21
MS_12 Receiver MS_22
MS_11 Transmitter MS_21
MS_12 Receiver MS_22
Danger Zone
MS_11 Transmitter MS_21
MS_12 Receiver MS_22
Danger Zone
MS_11 MS_21
Transmitter
MS_12 Receiver MS_22
Danger Zone
Danger Zone
Description
If the muting sensors i_bMutingSw_11(MS_11) and i_bMutingSw_12(MS_12)
are activated by passage of a workpiece within the time set in
i_dDiscTime11_12, muting mode is activated. (o_bS_MutingActive=ON)
Muting mode remains active as long as MS_11 and MS_12 are activated by a
workpiece. The workpiece may pass through the light curtain without causing
a machine stop.
Before muting sensors MS_11 and MS_12 are disabled, muting sensors
i_bMutingSw_21(MS_21) and i_bMutingSw_22(MS_22) must be activated.
This ensures that muting mode remains active. The time discrepancy between
switching of MS_21 and MS_22 is monitored by the time i_dDiscTime21_22.
Muting mode is terminated if either muting sensor MS_21 or MS_22 is
disabled by the workpiece. The maximum time for muting mode to be active is
the i_dMaxMutingTime.
4 SAFETY FB SPECIFICATIONS
69
4.11 M+SF_MUTEP_R
4