7. Menu 74 Parameters ALSPA PROFIBUS Field Bus Coupler
Page 7-8 Technical Manual (09/06)
7.4.13 Control Words P74.40 & P74.42
The PROFIBUS board can provide a source for two control word
parameters. Control flags are explained in the Getting Started
Manual T1676, but basically allow control of such functions as
starting and stopping via a single bit in a 16-bit parameter. The two
control word parameters are capable of controlling 32 control flags.
Normally, only one word of 16 control flags would be sufficient to
control the drive. If more than 16 control flags are needed, P74.42
can be used to hold a further 16 control flags. While any of the
received words can be mapped to this parameter, it is
recommended that the last word be used for the second control
word.
Control flags in the FBC control words are selected by specifying a
control flag source (CFSRC) value in the range 5.000 to 5.031 which
correspond to FBC bits 0 to 31 respectively.
The description of how to map control flag parameters to the drive’s
control flags in Menus 33 and 34 is given in manual T1676, and in
more detail in the Software Technical Manual T1679. The control
flag parameters also have an option of a fallback value if a loss of
Fieldbus reference is declared.
7.4.14 Received Data Parameters P74.50 to P74.69
In order to use the data received in the PPO, it must be placed
somewhere for the drive to use. These Parameters allow the
relevant PPO word to be placed in a destination parameter. While
some parameters can be directly written to, others, such as
references, cannot. For this reason a group of reference
parameters are available to hold the received reference. Menu 42
then points to these references for inclusion into the relevant
reference selector.
Each receive parameter pointer has an associated scale parameter.
This is to allow network units to be converted to drive units.
Internally, the drive represents 100.00% with a value of 10000. The
PROFIDRIVE profile can represent 100.00% with a value of 16384.
In order to scale received set point references to the drive’s internal
representation for 100.00% the parameters in menu 60 (see
7.5)
allow the user to specify what numerical value is being used by the
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