Siemens Simatic Ident Function Manual page 32

Setting parameters for blocks
3.4 Programming Ident blocks
With the readers. there are four different modes that you can select with the "ATTRIBUTE"
parameter.
● At the start, a certain duration/number (period of time, number of inventories, number of
"Observed" events or identified transponders) is specified. A distinction is made between
the following options:
– Duration
– Number of inventories
– Number of "Observed" events
Inventories are then taken by the reader for this time or number of inventories. When the
specified time/number is reached, the block is ended and returns all identified
transponders in "IDENT_DATA". In other words, other commands can only be executed
when all inventories have been taken completely. The unit (time or number) is specified
using "DUR_UNIT" and the value (time value or number) using "DURATION". This mode
can be executed using the attributes "0x80" and "0x81". Depending on the attribute, more
or less data is supplied about the identified transponders.
● With the attributes "0x86" (start "Presence_Mode") and "0x87" (end "Presence_Mode"),
inventories can be taken permanently. The presence of a transponder can then always
be queried using "PRESENCE" without needing to start the block with "EXECUTE". No
information about the identified transponders is returned when the command executes!
To obtain information about the identified transponders, use one of the two calls listed
above (with time / number of inventories = 0).
When this mode is active, commands relating to transponders are not executed
immediately but only when a transponder is identified. This achieves shorter reaction
times since the command is already pending when the transponder enters the antenna
field.
"Presence_Mode" is practical in the context of the "Repeat command" function.
The "NUMBER_TAGS" output parameter is used to output the number of identified
transponders. With the attributes "0x80" and "0x81" on completion of the read operation, the
sum of all identified transponders is displayed. With the attribute "0x86" the number of
currently identified transponders is shown at the "NUMBER_TAGS" output parameter (max.
15),without needing to start the module with "EXECUTE".
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Take inventories for a specified period of time
Take a specified number of inventories
Take inventories until a specified number of transponders have been identified at the
same time.
Ident profile and Ident blocks, standard function for Ident systems
Function Manual, 10/2018, C79000-G8976-C387-04