Chapter 9
244
Logic programming – Function blocks
Ensure that the transitions of the signals for restarting fulfill the requirements of
the safety standards and regulations!
In case of a short-circuit to High (to 24 V DC) at a physical input, the evaluated signal
can have a pulse when the signal is reset due to the short-circuit detection. If such a
pulse can result in a dangerous state in the machine, the following points have to be
observed:
Ensure protected cable laying for the signal line (due to cross-circuiting to other
signal lines).
No short-circuit detection, i.e. do not reference to test outputs.
Input parameters and input signals of the function block
The Press single stroke function block supports the following input signals:
Start/Release
The Start/Release input signal is used to indicate the beginning and the end of the
press movement. A rising edge (Low to High) at the Start/Release input signals a
start of the press. A Low Start/Release input signals a stop of the press. If the Mode
for Start/Release input parameter is set to Start only, the press cannot be stopped
by the Start/Release input signal.
Use additional safety measures when Start/Release is set to Start only!
If the Mode for Start/Release input parameter is set to Start only, you must use
additional safety measures (e.g. hazardous point protection with a light curtain).
Otherwise the operator of the press will be in danger.
If the Mode for Start/Release input parameter is set to Stepping and Restart
interlock is set to When Release 1 or Release 3 or Start/Release is Low or Always,
a valid restart sequence is required after a stop that was caused by a Low
Start/Release input signal.
The Enable output of a Two-hand control or of an N-break function block is
particularly suitable for connection to the Start/Release input.
Release 1 (static)
The Release 1 (static) input signal is mandatory. The Enable output always changes
immediately to Low, if Release 1 (static) is Low.
If this function block is used together with a press contact function block (e.g.
Eccentric press contact or Universal press contact), its Enable output must be
connected with the Release 1 (static) input of this function block.
Release 2 (start)
The input signal Release 2 (start) is optional. If Release 2 (start) is configured, the
Enable output can only change to High (e.g. during switching on), if Release 2 (start)
is High. If the Enable output is High, Release 2 (start) is no longer monitored.
Do not use the Release 2 (start) input for safety purposes!
Do not use the Release 2 (start) input for initiating safety stops, because this input is
evaluated temporarily during the start sequence only. Otherwise the operator of the
press will be in danger.
ATTENTION
ATTENTION
ATTENTION
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