User`s guide

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CHAPTER 8 - CFW-08 OPTIONS AND ACCESSORIES
8.25.2.3
Access to the
InverterData
All parameters and available basic variables for the CFW-08
can be accessed through the network:
Parameters: are those set in the inverter and that can be
displayed and changed throughthe HMI (Human-Machine
Interface) (refer to item I - Parameters).
Basic Variables: are theinternal invertervariables thatcan
be accessed only through serial interface. For instance,
through these basic variables you can change the speed
reference, read the inverter status, enable or disable the
inverter, etc (refer to item 8.24.5.1 - Basic Variables).
Register:nomenclatureused torepresent both parameters
and basic variables during data transfer.
Internal Bits: bits that are accessed only through the serial
interface and that are used for inverter status controlling
and monitoring.
Item 8.24.3.2 defines the resolution of the parameters and
variables transmitted via serial interface.
Available functions and response times:
In the Modbus RTU protocol specification is defined the
functions used for accessing different types of registers
describedinthe specification.In theCFW-08both parameters
and basic variablesaredefined asbeingholdingtype registers
(referenced as 4x). In addition to these registers, it is also
possible to access the internal controlling and monitoring bits
directly (referenced as 0x).
Following services (or functions) are available in the CFW-08
frequencyinverter for accessing these registers and bits:
Read Coils
Description: reading of internal register blocks or coils.
Function code: 01.
Broadcast: not supported
Response time: 10 to 20 ms.
Read Holding Registers
Description: reading of register blocks of holding type.
Function code: 03.
Broadcast: not supported
Response time: 10 to 20 ms.
Write Single Coil
Description: writing in a single internal bit or coil.
Function code: 05.
Broadcast: supported.
Response time: 10 to 20 ms.
Transmission rate and parity:
Both configurations are defined by parameter P312.
Baud rates: 9600, 19200 or 38400 bits/s.
Parity:none, odd parity or even parity.
All slaves and even the network master must use the same
baud rate and parity.