Omron NE1A-SCPU01 - 07-2009 Operation Manual page 226

Command Reference: Function Blocks
Note
192
Program Example
Limit switches 1, 2 connected to IN0, IN1 on the NE1A-series Controller is
connected to Muting Signal 11 of the Muting function block.
(1) Limit switches 1 and 2 are set to the dual channel complementary setting
for local inputs to evaluate the input data from the two switches.
(2) The Safety Door Monitoring function block is used as a substitute for the
Limit Switch function block. The input type for the Safety Door Monitoring
function block is set as Dual Channel Complementary (1 pair).
Muting Sequence
1. In figure 1 above, N.O. limit switch 1 is OFF and N.C. limit switch 2 is ON.
In addition, the light curtain is not obstructed, so the Output Enable signal
is ON. Muting Signal 11, which inputs the dual channel complementary
signal for limit switches 1 and 2, goes OFF.
2. As the robotic arm rotates, limit switch 1 goes ON and limit switch 2 goes
OFF as shown in figure 2. Muting Signal 11, which inputs the dual channel
complementary signal for limit switches 1 and 2, goes ON, so muting is en-
abled, and the Muting Status goes ON.
3. At this point, the Output Enable signal is kept ON even if the light curtain is
obstructed so the operator can access the work platform.
4. When the operator completes his task and the light curtain is unobstructed
as the robotic arm rotates, Muting Signal 11 goes OFF, the muting status
is cleared, and the Muting Status goes OFF.
■ Timing Chart
AOPD
Input 1 (NC)
AOPD
Input 2 (NC)
Muting
Signal 11
Output
Enable
Muting
Status
Section 8-5