Siemens SIMATIC S5 Manual page 17

Digital
To power
supply input IP247
Hardware
limit switch
start
\ \
s
brake
start
'brake
Fig, 1/1 Linear axis with limit switches
The positioning module also has a further stop input.
There is a digital input "external starVstop" for each axis, which must be wired up before starting
the system. This allows an axis to be stopped at any time regardless of whether it is being
operated from the PC or from the PG. Once again, this input cannot be regarded as a substitute
for emergency stop limit switches. Remember that depending on prior operation, this input can
also have the effect of an internal start signal.
When operating the plant with a PG, remember the following points:
If an axis is started from the programmer during installation and initial start-up, it continues to
move even if you exit the test display in which the start was triggered or switch off the program-
mer. Depending on the particular operation, the axis only stops when the target or a limit sw]tch
is reached. It is therefore strongly advised that you remain in the test display while the axis is tra-
versing.
When characters are entered at the programmer keyboard, they are written to a buffer. If charac-
ters are entered more quickly than they can be processed, they are stored temporarily in this
buffer. This can become noticeable in the test display of COM247 when entering commands, if,
for example, the commands "forward" and "reverse" are entered in quick succession. The execu-
tion then lags behind the input. A stop command is therefore only executed, when all the
commands stored before it in the character buffer have been processed.
The last job is completely executed unless it contradicts the second to last job.
s Traversing
brake
range
Digital
To power
input IP247 supply
Hardware
limit switch
end
\
s
s
\
brake
Machine'
end
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