Fuji Electric FRENIC-VG Series, User Manual

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5.1 Standard RS-485 Communications Ports
5-9
Chap. 5
USING ST
ANDARD RS-
485
5.1.6 Referencing and changing data
If the system does not have field options, writing to the S range (run operation command, command
data) via RS-485 constantly enabled.
Additionally, refer to the communications address, 485 No. in Chapter 4, Section 4.2 "Function
Code Tables" for details on referencing and changing function codes. Take note of restrictions such
as data ranges and disabled changes during operation.
5.1.6.1 Write restrictions for function codes
Writing to (selecting) function codes (F, E, C, P, H, A, o, L, U) is subject to the following
restrictions.
(1) Writing to volatile memory
In order to enable a high-speed writing response when writing via RS-485, the system uses volatile
memory (RAM: Random Access Memory, memory that is discarded when the system is switched
OFF). If you need to keep the data after the system is switched OFF, issue the H02 [Save All]
function code to write the data to non-volatile memory.
Writing using function code H02 takes about 2 seconds. Do not attempt to perform another write
operation while the system is writing data to the memory.
(2) Writing via RS-485 disabled mode
You will receive a negative response if you attempt to write to any of the following function codes.
Code Name Reason
P02 M1 mode selection Other codes are automatically updated when P02 is changed. Updates are generally
written to non-volatile memory. For P02 only, however, updates are written to volatile
memory (discarded when system switched OFF), resulting in inconsistent codes when
the system is switched OFF and ON again.
Only change P02 via the keypad. However, writing is enabled when using
FRENIC-VG Loader software (SX protocol).
H31 Station address If changed, communications operations are disabled
H34
to
H37
(UART setting) RS-485 hardware settings
H40 Protocol selection If changed, communications operations are disabled
(3) Continuous writing disabled mode
When using ModBus RTU, you can continuously write 16 pieces of data. When doing so, do not
include the following codes in the continuous write group. If you attempt to write with these codes
in the group, the system will return a negative response. Fuji general-purpose inverter protocol and
ModBus RTU can be written individually.
Code Name Reason
H02 Save all function
H03 Data initialization
H68 Alarm data deletion
H79
Cooling fan cumulative run
time default setting
H80
Main circuit condenser
capacity default setting
H81
Main circuit condenser
cumulative lifetime default
setting
Internal data is updated at the same time as operation is performed.
This updated data is overwritten by continuously written data.