Mitsubishi Electric WS0-CPU0 Operating Manual page 248

Chapter 9
ATTENTION
Note
ATTENTION
245
Logic programming – Function blocks
Release 3 (safety)
The Release 3 (safety) input signal is an optional signal. The Enable output can only
change from Low to High if Release 3 (safety) is High. If Release 3 (safety) is Low
and Upstroke is Low, the Enable output is set to Low and a restart sequence has to
occur in accordance with the settings.
If Release 1 (static) and Upstroke are High and the maximum upstroke muting time
is configured to a value higher than 0, the Release 3 (safety) signal is muted.
Top
The Top input signal is used in order to determine the end of the press cycle (i.e. the
press has reached the top dead center). This signal is available at the function blocks
Eccentric press contact or Universal press contact. The Top input signal is used for
single-stroke protection. The Enable output changes to Low when the Top input
signal changes from Low to High.
Do not use the Top input for safety purposes!
Connect the Top input only with the Top output of an Eccentric press contact or
Universal press contact function block or to an equivalent signal source. Do not use the
Top input for initiating safety stops. Otherwise the operator of the press will be in danger.
Mode for upstroke muting
If the Max. Up-Stroke muting time is not set to 0, the Upstroke input has to be
connected.
Connect the Upstroke input only with the Upstroke output of an Eccentric press
contact or a Universal press contact function block.
In this case, the Release 3 (safety) and Start/Release input signals are muted
(muting of the Start/Release input depends on the parameter settings) when the
Enable output is High and the Upstroke input is High. This function block does not
carry out a plausibility check of the Upstroke input signal. If the Upstroke input is
High several times during a single press cycle, it is possible to mute the corresponding
input of the function block several times. If a signal shall not be muted, it should be
connected to the Release 1 (static) input by means of an AND function block together
with other signals that have to be connected to the Release 1 (static) input.
Exclude any danger during the upstroke movement of the press!
If you use upstroke muting, you must ensure that during the upstroke period no
hazards are present, e.g. by the up movement itself.
Max. Up-Stroke muting time
The Max. Up-Stroke muting time can be configured. This time begins with the rising
edge (Low to High) of the signal at the Upstroke input. If the timer reaches the
configured Max. Up-Stroke muting time before a falling edge (High to Low) occurs at
the Upstroke input, the function block terminates the muting of the Release 3 (safety)
and Start/Release inputs. If from this moment on one of these two inputs becomes
Low, the Enable output is also set to Low.