7.4 Variable area
7-9
Communication
(Modbus)
Channel identifier
For multi-point input types that require settings for channels 2 to 4,
specify 1 to 3 to identify the channels.
On single-input types, only "0: Channel 1" can be specified.
In-area address
This is a number that is assigned to each set of data in the variable
area. Addresses are assigned in order beginning from the first set.
For more information on addresses, see the Modbus section in
"Appendix Setting list" (P.A-6). Note that the addresses indicated in
the variable area map are addresses of channel 1.
For example, to specify an address of channel 2 on a multi-point input
type, add H'4000 to the address in the variable area map. For channel
3 add H'8000, and for channel 4 add H'C000.
● Number of
elements
The number of elements is expressed as a 2-byte hexadecimal value.
The specification range for the number of elements varies depending
on the command. See "7.9 Commands and responses (Communi-
cation/Modbus)" (P.7-17).
For example, if the number of elements is 0010, the first 8 elements of
data (H'10) from the address are specified.
In Modbus protocol one element is two bytes of data, however, setting
data on the E5AR/ER is four bytes.
● Set values Values read and written to the variable area are expressed in
hexadecimal and disregard the decimal point position (negative values
are expressed as a two's complement).
Example: D'105.0
→ H'0000041A
The variable is an 8-digit number in hexadecimal. Negative
values are expressed as a two's complement. The decimal is
disregarded.
For example, if the PV of the E5AR/ER is 105.0, it will be
read as H'0000041A (105.0
→ 1050 → H'0000041A).
Use of the variable area on the E5AR/ER is explained in the following
sections.
Channel identifier Channel
0 Channel 1
1 Channel 2
2 Channel 3
3 Channel 4
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