Toshiba VF-A7 - Manual (Page 31)

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0xFD00 (Modbus holding register 0xFD01), which can therefore be accessed via
Modbus holding register 0x0D01 (3329
10
) when register remapping is enabled.
When register remapping is enabled, only accesses to Modbus registers 0x0A01 –
0x1000 are affected: the normal locations for the critical control and status registers
remain unaffected and can still be accessed (i.e. Communication Frequency
Command will be updated via writes to either register 0x0A02 or 0xFA02: both will
write to ASD register 0xFA01).
Refer to section 11.2 for further information regarding configuration of the register
remap selection.
10.5 ASD Scan Registers
Scan registers are used to define ASD registers that the user wishes to access
quickly. ASD registers that are configured to be scan registers will have their data
mirrored locally on the ETH-100. Requesting the data from or writing data to an
ASD register that is set up to be a scan register will take less network time because
the ETH-100 simply accesses a local value instead of initiating a transaction with the
ASD to process the data.
Refer to section 11.3.2 for further information regarding configuration of the scan
registers.
10.6 Modbus Programmable Pointer Registers
Programmable pointer registers (PPR) allow the user to access non-consecutive
Modbus registers with only one Modbus transaction
. Modbus register locations
0xFC00 ~ 0xFC0F are reserved by the ETH-100 to access the registers defined in
the PPR section of the "channels" page of the ETH-100's embedded web server. For
example, if you would like to continuously read the data from ASD registers 0xFD00,
0xFE01, 0xFE04 and 0xFE05, the standard Modbus register configuration would
require 3 read commands to be issued: one reading 1 Modbus register starting at
register 0xFD01, one reading 1 Modbus register starting at register 0xFE02, and one
reading 2 Modbus registers starting at register 0xFE05. To conserve network
bandwidth and speed processing time, however, the programmable pointer registers
can be used to allow the same information to be accessed, but by only issuing 1
command which reads 4 Modbus registers.
To configure this function, enter the register numbers of the Modbus registers you
would like to continuously access into the PPR section of the embedded web server's
"channels" page (refer to section 11.3.3). For example, we could set PPR register
location 0xFC00 to a value of 0xFD01 (the first Modbus register number we want to
access), register location 0xFC01 to a value of 0xFE02, register location 0xFC02 to a
value of 0xFE05, and register location 0xFC03 to a value of 0xFE06. The 4 registers
that are to be monitored can now be accessed simply by issuing 1 Modbus holding
register read command with a length of 4 starting from Modbus register location
0xFC00. The returned data will be the data obtained from ASD registers 0xFD00,
0xFE01, 0xFE04, and 0xFE05 (in that order). IMPORTANT: Note that PPR values
refer to MODBUS registers. That is, Modbus registers = ASD registers + 1.