ABB RCNA-01, User Manual

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Communication
34
Assembly object
I/O Assembly Instances may also be referred to as Block Transfer
of data. Intelligent devices realising a Functional Profile, such as
the RCNA-01, have several objects. Since it is not possible to
transmit more than one object data through a single connection, it
is practical and more efficient to group attributes from different
objects into a single I/O connection using the Assembly object.
The Assembly object acts as a tool for grouping these attributes.
The Assembly selections described above are in fact Instances of
the Assembly object class. The RCNA-01 uses Static assemblies
(in other words, fixed groupings of different object data only),
except for the Vendor Specific Assembly. These are predefined
and cannot be changed.
The following tables describe the predefined assembly instances
supported by the RCNA-01.
Note: Add 4 extra bytes (2 words) to all the input assemblies; for
example, the total size of Input Assembly Instance 70 is 4 bytes +
4 extra bytes = 8 bytes. For output assemblies, the extra bytes
must not be added.
The configuration parameter 26 VSA I/O SIZE must be configured
without these extra bytes.
BASIC SPEED CONTROL assembly
The BASIC SPEED CONTROL assembly is defined by the
ControlNet AC/DC Drive Profile. The format of the output
assembly is:
Instance 20 (Output assembly)
Byte Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2
Bit 1 Bit 0
0 Fault reset Run fwd
1
2
Speed Reference (Low Byte) *
3 Speed Reference (High Byte) *
* Scaling of Speed Reference is configured by Speed Scale attribute in AC/
DC-Drive Object (class 0x2A, instance 0x01, attribute 0x16), and it defaults
to 1 rpm.