Weidmuller WI-I/O-9-U2: Wireless Mesh I/O & Gateway User Manual V1.2.2 - Manual (Page 57)

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Analog mappings are triggered when the input has changed by a predefined value,
which is
called ‘Sensitivity’. This is set by configuring a Sensitivity block for the particular
input or a range of inputs. (See section 4.3.12 for more details on setting these
Sensitivity Blocks)
The second method ‘Updates’ is a message that is sent on a preconfigured time
regardless of the input value or state. The default update time is 10 minutes however it
can be increased to a maximum of 18 Days-12 hours and 15 seconds or decreased to a
minimum of 1 second. Updates can also be disabled buy entering a time of zero or
ticking the check box.
It should be noted that the ‘Updates’ are only a check signal and care should be
taken when configuring the update values with short update times (< 5 seconds)
as it will greatly increase the amount of radio traffic.
There are three different types of mappings, Write, Gather/Scatter and Read
Mappings, which are explained below. Each mapping has certain advantages or
disadvantages over the other mappings. The correct mapping to use will depend on the
data and requirements of the system.
Write Mapping
A multi I/O mapping allows multiple sequential values to be sent in one message. If
mapping analog values the maximum I/O count is 64 however if mapping digitals it can
be as many as 1024 as the digitals values are packed into 16 bit words for transmission.
The mapping will be sent on a change of state of any of the values being monitored and
on an update period.
Gather Scatter Mapping
A Gather Scatter Mapping is essentially the same as a Write Mapping however instead
of sequential register it allows different I/O types to be sent in a single message. All I/O
types
– Digital, Analog, Long (32bit registers) and Floating point values can be sent in
the one message. A Gather Scatter Mapping has a maximum I/O count of 32 values
which can be any data type, i.e. digital, analog, longs or floats.
Read Mappings
Read Mappings are similar to Write Mappings in that they allow multiple sequential
values to be sent however instead of writing the values to another module it sends a
message or polls the sending module and requests the values to be sent. Generally this
type of mapping is more like a polling system in that the receiving station initiates when
it wants to communicate, i.e. sending out a read request when it requires the
information or on a timed basis.