Mitsubishi Electric MELSEC iQ-R Series Safety Function Block Reference page 83

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, sequential muting with four muting sensors is used. An
explanation for transporting of workpieces in forward direction is provided in the table below. 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) as well as the
OSSD signal (i_bS_AOPD_In) from the "active opto-electronic protective device". For forward direction, from the time when
i_bMutingSw_11/12 are sequentially set to ON and then i_bMutingSw_21/22 are sequentially set to ON until when only
i_bMutingSw_22 is set to ON, 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 then only i_bS_Muting_11 is set to ON.
■ Example for M+SF_MUTES_R in forward direction with four sensors
Figure
Transmitter
MS_11 MS_12 Receiver
Transmitter
MS_11 MS_12 Receiver
Transmitter
MS_11 MS_12 Receiver MS_21 MS_22
Transmitter
MS_11 MS_12 Receiver MS_21
Danger Zone
MS_21 MS_22
Danger Zone
MS_21 MS_22
Danger Zone
Danger Zone
MS_22
Description
If the muting sensor i_bMutingSw_11 (MS_11) and then i_bMutingSw_12
(MS_12) are activated by passage of a workpiece, the muting mode is
activated.
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.
Muting mode is terminated if only muting sensor MS_22 is activated by a
workpiece.
4 SAFETY FB SPECIFICATIONS
81
4.12 M+SF_MUTES_R
4