Lenze PLC Designer PLC Designer (R2-x) - Manual (Page 399)

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DMS 3.2 EN 02/2011 TD29 397
The following options can be activated or deactivated in configuring the transmission
behavior of the variables:
Pack variables: The variables are assembled for transfer into packets (telegrams)
whose size depends on the network. If the option is deactivated, a packet is set up for
each variable.
List identifier (COB-ID): Identification number of the first packet, in which the
variables will be sent. (default = 1). Further packets will be numbered in ascendent
order. Note: A COB-ID must be unique within all network variables lists used in the
project. Using the same ID in multiple list configurations will cause a compile error
with compiler versions >= 2.3.7.0.
It depends on the target system, whether the network variables of the list can be
defined to be 'readable'
and
'writing'' or exclusively one of both. To set this property
activate the respective options 'Read' and 'Write':
Read: The variables in the list will be read; if the option is deactivated, further
variables sent over the net will be ignored. The following option can be activated in
addition:
Request at Bootup: If the local node is a "reading" node (Option 'Read' activated),
then as soon as it gets re-booted the actual variable values will be requested from
all writing nodes and will be sent by those, independently of any other transmit
conditions (time, event), which normally trigger the communication. Precondition:
In the configuration of the writing nodes the option 'Answer Bootup requests'
must be activated ! (see below).
Write: The variables will be written, the following options can be set additionally:
Include Checksum: A checksum will be added to each packet which is sent. The
checksum will be checked by the receiver to make sure that the variable
definitions of sender and receiver are identic. A packet with a non-matching
checksum will not be accepted and – if this is configured ('Use acknowledge
transfer', see below) – will be acknowledged negatively.
Use acknowledged transfer: (no function in case of CAN) :Each message will be
acknowledged by the receiver. As soon as the sender does not get at least one
acknowledgement within a cycle, an error message will be produced which in case
of an UDP-network will be written to the diagnosis structure provided by
NetVarUdp_LIB_V23.lib.
Answer Bootup requests: If the local node is a "writing" node (Option 'Write'
activated), then each request of a reading node which is sent by it at bootup
(Option Request on Bootup, see above), will be answered. That means that the
actual variable values will be transmitted even if none of the other defined
transmission triggers (time or event) would force this at this moment.
Cyclic transmission: Variables are written within the intervals specified after
Interval. (time notation e.g. T#70ms).