Mitsubishi Electric WS0-CPU0 - Function Blocks for Dual Channel Evaluation

Chapter 9
187
Logic programming – Function blocks
9.9 Function blocks for dual channel evaluation
The MELSEC-WS safety controller supports applications up to SIL3 (in accordance
with IEC 62061) and Performance Level (PL) e (in accordance with EN/ISO 13849-1).
Possible sources for function block inputs are one or two safety signals connected
locally to the MELSEC-WS safety controller. You can choose between the following
input evaluations (depending on the function block):
 Single-channel
 Dual-channel:
– Dual-channel equivalent (1 pair)
– Dual-channel complementary (1 pair)
– Dual-channel equivalent (2 pairs)
– Dual-channel complementary (2 pairs)
The following truth tables summarize the internal evaluation for the individual types of
input signal evaluations of the MELSEC-WS safety controller.
Truth tables
The following applies for the truth tables in this section:
“0” means logic Low.
“1” means logic High.
“x” means “any” = “0” or “1”.
The Fault present output is High when the logic processing of the MELSEC-WS safety
controller detects an error in the combination or in the sequence of the input signals.
9.9.1 Single-channel evaluation
The following relates to the Safety gate monitoring and Emergency stop function
blocks.
This evaluation type has no functional use since the Enable output always has the
same value as Input 1A and the Fault present output is always Low. Therefore this
option may be useful only for the graphic arrangement of the logic program.
Regardless of that, the related input element can be used directly in the logic instead
of connecting it to Input 1A.
Note
Figure 174:
Example for single-channel
evaluation
Note