Download Siemens SIMATIC NET Specifications

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Special Address Events
!SWITCH:DEVICE
Toggles the communication path between the current and backup
device when any value is written to a Digital Output or Analog Output
block.
!MODE
Enables polling to the channel, device, or datablock specified when a
value of 1 is written to a Digital Output block (Analog Output blocks
are not supported). Disabling a specified object occurs when a value
of 0 is written to a Digital Output block.
!POLL
Triggers a demand (one-shot) poll of one of the following when any
value is written to a Digital Output or Analog Output block:
•
A channel and all of its devices and datablocks
•
A device and all of its datablocks
•
A specified datablock
Using demand polling does not affect the configured poll rate of the
datablock. For example, if you demand poll a datablock 15 minutes
into a 30-minute scan cycle, the driver polls the datablock again in 15
minutes, as originally scheduled.
!SEND
Sends a special command to the specified datablock when any value is
written to a Digital Output block. The command is sent only if the
Block Writes option is enabled in the datablock. The command
instructs the driver to send all outstanding writes for the specified
datablock to the process hardware in a single message.
When the driver sends its outstanding writes, it also sends the last
known values of any unmodified data in the datablocks that are
changing. Consequently, we recommend relatively short poll times
for datablocks you write to so that the driver will have the most up-todate data.
You cannot use an Analog Output block to trigger block writes.
For more information about using Block Writes, refer to Feature:
Block Writes.
Chapter 10. Configuring the I/O Driver from FIX/iFIX Applications 165