User manual

915U-2 Wireless I/O Page 49
Page 49 User Manual
4.2.2 Mappings
Mappings are configured by selecting the “Units”, “Mappings” then “Add”.
Figure 29 - Mappings
There are three types of mappings, Write, Gather/Scatter and Read Mapping.
Write Mapping
A multi I/O mapping that 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.
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. With a Gather Scatter Mapping a maximum I/O count is 32 values
and these values can be any 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 receiving module and requests the values.
Mappings are configured by select the Mapping Type and Destination and then
configure the I/O table. By clicking in the Local Name cell you can select an I/O point
(Input) that you wish to map, then select the Remote Name cell to add I/O point (Output)
for the destination.
There is also and I/O count which will allow the addition of more I/O points to the
mapping. In a Write and Read mapping they will consecutive registers however in
Gather/Scatter Mappings they can be selected from anywhere within the I/O table
The other mapping parameters are available on the same screen, i.e. Update Times,
Offset Times, Change of State delay or even disabling the COS completely. You can
also configure a Comms Fail output indication or configure a trigger register that will
force the mapping to be sent.