Fast Shut Off And Fast Shut Off With Bypass - Mitsubishi Electric WS0-CPU0 Operating Manual

Chapter 9
Figure 112:
Function block diagram for
the Fast shut off and Fast
shut off with bypass
function blocks
Note
Figure 113:
Fast shut off example
Note
139
Logic programming – Function blocks
9.7.12

Fast shut off and Fast shut off with bypass

Function block diagram
General description
The Fast shut off and Fast shut off with bypass function block is used to minimize the
response time of a safety switching path within the MELSEC-WS safety controller. To
use this block, both the input and output for the switching path must be connected to
the same safety I/O module (i.e. WS0-XTIO). This is necessary because the Fast shut
off function block generates a direct switch off at the safety I/O module resulting in a
shorter switch off time which is independent of the logic execution time.
For the Fast shut off function block, the consequence of this is that logic between the
Fast shut off input and the Fast shut off output cannot hinder a switch off when the
Fast shut off is activated.
The Fast shut off with bypass function block however allows to temporarily bypass the
Fast shut off function using the bypass input.
The Fast shut off with bypass function block is only available with WS0-XTIO with
firmware version V2.00 or higher.
Example: In the following logic example, the C4000 will switch off the Q2 motor.
Simple logic such as this can be accomplished within the Fast shut off function block
itself (see how to configure below).
The signal path from the output of the Fast shut off function block to the physical
output that is selected in the Fast shut off function block must be configured in such
a way that switching off of the output of the Fast shut off function block always
results in a direct switching off of the physical output as well. Typically the AND,
Restart or EDM function blocks can be used in the signal chain for this. An OR
function block however does not comply to this rule.