Operating And Display Elements - Siemens SIMATIC PP7 Equipment Manual

1.2

Operating and Display Elements

Standard operating
The Push Button Panels are all equipped with a keyboard containing short-
and display ele-
stroke keys. The individual keys can be configured in respect of their function
ments
as either switches or keys.
Function momentary–contact switch:
Function switches: Pressing the key sets the corresponding bit, pressing
Two LEDs are integrated in the keys and are used to display the bit status of
the connected PLC. The LEDs can indicate four different statuses, one of
which can be defined via parameters.
Operating concept All the operating elements of the Push Button Panels are linked to bits in the
PLC. The keys on the Push Button Panel can be used to influence the bits in
the PLC and thus control the affect of processes. At the same time, the LEDs
indicate the bit status of the PLC and, thus, the operating status of the process
being monitored.
When several keys are pressed simultaneously, it is detected by the Push But-
ton Panel and the bits are set in the PLC. After restarting the system following
a power failure, all the bits are set to 0.
Digital inputs and Additional 22.5 mm elements can be connected using the digital inputs and
outputs outputs. Non-connected digital inputs are automatically set to 0.
Release input The release input serves to lock the Push Button Panel. A key-operated switch
can be connected here, for example. The release input permits switching be-
tween normal operation (open contact) and monitoring mode (closed contact).
In normal operation, all the functions on the Push Button Panel are available
for use, whereas in monitoring mode, the following restrictions are valid
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The corresponding bit in the PLC is set as long as the
key is pressed.
again resets it.
the inputs are locked, no signal exchanges are reported to the PLC,
the last status of all the keys is maintained by the PLC until normal
operation returns.
PP7, PP17-I, PP17-II Equipment Manual
Release 06/98
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