21
4.2
Scanned Parameters
The interface card provides network access to the specified list of parameters contained in the
param.xml
file located in the “
WEB
” folder of the interface card’s file system. These parameters are
constantly being read and/or written (as applicable), and their current values are therefore mirrored in
the interface card’s internal memory. Only those parameters specified in the
param.xml
file will represent
meaningful values.
The principle disadvantage of scanned parameters is that write data checking is not available. This
means that when the value of a scanned parameter is modified via a network protocol or via the web
browser’s monitor tab, the interface card itself is not able to determine if the new value will be accepted
by the inverter (the value may be out-of-range, or the inverter may be in a state in which it will not accept
new values being written via communications, etc.) For example, if a write is performed to a scanned
command parameter with a data value that is out-of-range, the interface card will not generate a
corresponding error. However, if end-to-end confirmation of such data writes is required, then the
parameter can be read over the network at a later time to confirm that the written value “took hold” in the
inverter.
Accesses to any parameter (?.00 to ?.99, where “?” is any valid parameter group number from Table 13)
will always be successful. Even if an inverter parameter corresponding to a given register does not exist
in the
param.xml
file, the interface card still maintains a placeholder location in its internal mirroring
memory for that parameter. This feature allows for the block access of non-contiguous registers
(parameters) as described in section 4.1. Care must be taken to utilize only the parameters that are
known to exist and that are also specified in the
param.xml
file.
4.3
Commonly Used Parameters
For a complete listing of all available parameters, their bit mappings, scaling values, etc., please refer to
the
A1 Instruction Manual
. As a user convenience, several commonly-used parameters are described
in the following sections.
4.3.1 Run command (00.02)
Parameter 00.02 (register 3) is used to command the inverter over communications. The structure of
parameter 00.02 is defined in Table 14. To stop the inverter, clear both the FWD and REV bits.
Table 14: Run Command
Bit
Signal
Description
0
1
0
FWD
Disable run forward
Run forward command
1
REV
Run reverse command
Disable run reverse
2
RST
-
Fault reset (when inverter
is in fault status)
3 to 15 Reserved -
-
Parameter 00.02 is only applicable if parameter 20.02 is set to a value of 8 (Fieldbus).
4.3.2 Frequency command (00.04)
Parameter 00.04 (register 5) is used to set the frequency command over communications and is not
saved to EEPROM. The frequency command is specified in units of 0.01Hz. For example, to set the
frequency command to 60.00Hz, command a value of (60.00Hz / 0.01Hz) = 6000 (decimal) or 0x1770
(hexadecimal).
Parameter 00.04 is only applicable if parameter 22.03 is set to a value of 4 (Fieldbus).