WI-GTWY-9-xxx Wireless Gateway V1.18
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To get around this problem, it is possible to configure “block mappings”. With a block mapping,
multiple registers (a “block of registers”) can be transferred together in the one radio message.
This improves the efficiency of the radio communications.
Read/Write Mappings
The mappings can be “read” or “write” mappings. A Read mapping is a request sent to another
WI-GTWY-9-xxx to return a block of values. A Write mapping is a message sending a block of
values to another WI-GTWY-9-xxx. A Read mapping from WI-GTWY-9-xxx#2 to WI-GTWY-
9-xxx#3 could be the same as a Write mapping from WI-GTWY-9-xxx#3 to WI-GTWY-9-
xxx#2 (that is, in the reverse direction) - except the Read mapping is initiated from #2 and the
Write mapping is initiated from #3.
Word/Bit Mappings
Read and Write mappings are also selected as Word or Bit mappings - that is, you can select a
Read Word mapping or a Read Bit mapping and you can select a Write Word mapping or a Write
Bit mapping. “Word” refers to a complete 16-bit register value; “Bit” refers to the value of the
most significant bit of a register - this bit is the “binary value” or “digital value” of the register.
If you use a Word block mapping of 50 registers, you are transferring a block of 50 x 16-bit
values. If you use a Bit block mapping of 50 registers, you are only transferring the digital value
of each register - that is 50 x 1 bit values. This is a lot more efficient for a radio message, but
bit mappings are only suitable for discrete or digital I/O. A Bit mapping will convert the 16-bit
register to a single bit, transfer it and store the bit value in the most significant bit of the
destination register.
Note: The maximum block size for each block mapping is 64 registers.
REMOTE
WI-
GTWY-9-
xxx
BLOCK OF I/O
REGISTERS
ACKNOWLEDGMENT
BLOCK WRITE
MESSAGE
BLOCK OF I/O
REGISTERS
READ REQUEST
BLOCK READ
MESSAGE
LOCAL
WI-
GTWY-
9-xxx
