Siemens Simovert Masterdrives Compendium page 522

Communication / CBC
Rules for task/reply
processing
8.4.4.3 Process data area (PZD)
NOTE
8.4-24
♦ The length of the task or reply is always 4 words.
♦ The least significant byte (in the case of words) or the least
significant word (in the case of double words) is always sent first.
♦ One task or one reply can only relate to one parameter value.
♦ The slave does not send the reply to a parameter task until the data
are received from the MASTERDRIVES unit.
During normal operation, this lasts 20 to 150 ms, depending on the
type of MASTERDRIVES unit.
♦ In certain states of the converters (especially in initialization states),
parameter processing is not carried out at all or only with a long
delay. Here, a delay of up to 40 seconds can be expected for the
reply.
♦ The master can only issue a new parameter task after receiving the
reply to a previously issued task.
♦ The master identifies the reply to a task which has been set:
• By evaluating the reply ID
• By evaluating the parameter number, PNU
• If necessary, by evaluating the parameter index, IND
• If necessary, by evaluating the parameter value, PWE.
♦ The task must be sent complete in one telegram; telegrams with
split tasks are not permissible. The same applies to the reply.
Control words and setpoints (tasks: master → converter) or status
words and actual values (replies: converter → master) can be
transferred by means of the process data.
The transferred process data only come into effect if the used bits of
the control words, setpoints, status words and actual values have been
routed (softwired) to the dual-port RAM interface.
For softwiring of the PZD, the number i of the process data (PZDi, i = 1
to 16) is entered in the connection value.
The process-data connection as described here does not apply if a
technology board has been mounted.
If a technology board (e.g. T300, T100) is used, the process-data
connection is indicated the technology board manual.
6SE7087-6QX70 (Version AL)
Compendium Motion Control
03.2010
Siemens AG
SIMOVERT MASTERDRIVES