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42 Wonderware Siemens SIMATIC NET S7 I/O Server

Predefined Item/Point Names

All S7 topics have predefined item/point names to monitor and control communication

properties.

UPDATEINTERVAL Item

The UPDATEINTERVAL item is used to access the currently set update interval. It is

the same value displayed in the monitor window of the S7 server. It indicates the

currently requested update interval in milliseconds. If the corresponding topic is

configured for "Enable I/O access to update interval", a client can poke new values into

this item. In any case the value can always be read through I/O. The range of valid

values differs with respect to the topic settings. The value of zero indicates that no items

on that topic are updated.

I/O Type: INTEGER

ACCESS: READ/WRITE (if configured)

RANGE: 1.. 2147483647

0 (topic inactive, no items are updated)

Note By poking a value of zero into the update interval item a client can conveniently

stop all update activities on the corresponding topic without having to deactivate the

items.

MAXINTERVAL Item

The MAXINTERVAL item is used to access the measured maximum update interval in

milliseconds of all items of the corresponding topic for the last completed poll cycle. It

is the same value displayed in the monitor window of the S7 server under "Longest

Interval". This item is read only. The value of the slowest item is displayed.

I/O Type: INTEGER

ACCESS: READ

RANGE: 0..2147483647

Note Use the UPDATEINTERVAL and MAXINTERVAL items to conveniently tune

the performance of the communication via I/O.

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Siemens SIMATIC NET Guia do Utilizador Página 46