Rockwell Automation 1752-L24BBBE SmartGuard 600 Controllers User Manual - Manual (Page 224)

224 Rockwell Automation Publication 1752-UM001E-EN-P - June 2014
Appendix D Function Blocks Command Reference
The Light Curtain monitoring function block monitors a type-4 safety light
curtain. The Output Enable signal turns on when the inputs from the safety light
curtain being monitored are active. The Output Enable signal turns off if the
inputs become inactive or if an error is detected for the function block.
You can use a Discrepancy Error output when programming the LC function
block. To display this optional diagnostic output, check the Discrepancy Error
checkbox on the Out point tab of the Function Block Properties dialog box in the
Logic Editor of RSNetWorx for DeviceNet software.
A Fault Present output can also be used in programming. To enable this optional
output, check the Fault Present checkbox on the Out point tab of the Function
Block Properties dialog box of the Function Block Properties dialog box.
Light Curtain Function Block Parameters
Set these parameters for the LC function block.
Light Curtain Function Block Truth Tables
In the truth table, 0 is off and 1 is on.
Light Curtain Function Block Error Handling
A discrepancy error is generated when one of the inputs is not in its correct state
for longer than the Discrepancy Time. For example, in Dual Channel Equivalent
mode, both inputs must be active (on) within the Discrepancy Time or an error
occurs.
Table 13 - LC Function Block Parameters
Parameter Valid Range Default Setting
Input Type Dual Channel Equivalent
Dual Channel Complementary Dual Channel Equivalent
Discrepancy Time 0…30 s in 10 ms increments. (1)
The discrepancy time must be equal to or greater than
the cycle time of the controller.
(1) A discrepancy time check is not performed when the discrepancy time is set to 0.
30 ms
Table 14 - Truth Table for LC Function Block
Dual Channel Equivalent Dual Channel Complementary
Input 1 (NC) Input 2 (NC) Output Enable Input 1 (NC) Input 2 (NC) Output Enable
0 0 0 0 0 0
0 1 0 0 1 0
1 0 0 1 0 1
1 1 1 1 1 0