NDC BETA LaserMike LaserSpeed Pro 8500-4, Instruction Handbook Manual

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10-4 LaserSpeed Pro 8500-4 Instruction Handbook:
PROFINET I/O™
Bit: 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Word
0:
Response Code T Command Code
Word
1:
Command Qualifier
Word
2:
Command/Response Data
Word
3:
T: Toggle Bit
The LaserSpeed Pro gauge processes the output data PWK request header under the following circumstanc-
es:

The command code is different from the last command code processed

The command qualifier is different from the last command qualifier processed

The command code represents a “read long” or “read float” request. This allows the master to con-
tinuously read a single database item without needing to issue an intervening request.

A Profinet IO master should always keep the “response code” bits clear in the input data PKW re-
quest header.
The LaserSpeed Pro gauge makes no direct use of the “toggle bit,” other than to reflect the state of the toggle
bit in the output data request PKW header within the input data response PKW header. This is done whether
or not the LaserSpeed Pro gauge processed the command.
The command code is used to request a particular PKW service. The available PKW command codes are
detailed later in this document.
The command code qualifier is used to carry additional information relating to the command. This includes
enumeration indices, database item identifiers, string segments, etc.
The command data is used by the master to send long, float or string information. The gauge uses the com-
mand data to provide enumeration, limit, value, and string data as appropriate according to the command
code.
10.3.1 Detection of Matching PKW Response
After a master has initiated a PKW command by setting the PKW request header appropriately, it must wait
for a matching response from the LaserSpeed Pro gauge.