DVP-ES2/EX2/EC5/SS2/SA2/SX2/SE&TP Operation Manual - Programming
4. S
3
: Address of the data to be accessed. If the address is illegal for the designated
communication device, the communication device will respond with an error message and
DVP-PLC will store the error code and associated error flag will be ON. If the function code
is K23, S
3
only can specify a data register. Besides, S
3
is a data register from which data is
read, S
3
+1 is a data register into which data is written.
Associated registers and flags indicating errors on PLC com ports: (For detailed information
please refer to Points to note of API 80 RS instruction.)
For example, if 8000H is illegal for DVP-PLC, the error will be in indicated by different set of
flags and registers. For COM2, M1141 will be ON and D1130 = 2; for COM1, M1315 = ON
and D1250 = 3, for COM3, M1319 = ON and D1253 = 3. Please check the user manual of
DVP-PLC for error code explanations.
5. S: Registers for storing read/written data. Registers starting from S stores the data to be written
into the communication device or the data read from the communication device. If the
function code K23 is used, S is a D device index which indicates the device in which the
communication data string received will be stored, and S+1 is a D device index which
indicates the device in which the data which will be written is stored. If a reading function
code (K2, K3, K4, or K23) is sent through COM2, the communication data string received will
be stored in the register indicated by S, and the conversion data will be stored in
D1296~D1311. Please refer to program example 1 and program example 3 for more
information. If a reading function code (K2, K3, K4, or K23) is sent through COM1 or COM3,
the conversion data will be stored in the register indicated by S. Please refer to program
example 2 and program example 4 for more information. Users can refer to example 13 and
example 14 for more information about the function code K23.
6. n: Data length for accessing.
When S
2
(MODBUS function code) is specified as H05 which designates the PLC force
ON/OFF status, n = 0 indicates ON and n = 1 indicates OFF.
When S
2
is specified as H01, H02, H03, H04, H0F, H10, H17 which designate the data
length for accessing, the available set range will be K1~Km, where m value should be
specified according to communication modes and COM ports as the table below.
(H01/H02/H0F, unit: Bit. H03/H04/H10/H17, unit: Word.) If the function code is H17, n is the
number of data registers from which data is read, n+1 is the number of data registers into
which data is written.
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