5. Access Procedure
32
Festo P.BE-CMMP-CO-SW-EN 0708NH
Transmission type
transmission_type and inhibit_time
Which event results in sending (transmit PDO) or evaluation
(receive PDO) of a message can be determined for each PDO:
Value
Meaning
Permitted
with
01
h
… F0
h
SYNC-Message
The numerical value specifies how many SYNC
messages must be received before the PDO
- is sent (T-PDO) or
- evaluated (R-PDO)
TPDOs
RPDOs
FE
h
Cyclical
The transfer PDO is cyclically updated and sent by
the motor controller. The time period is set by the
object
inhibit_time
.
Receive PDOs, in contrast, are evaluated
immediately after reception.
TPDOs
(RPDOs)
FF
h
Change
The transfer PDO is sent when at least 1 bit has
changed in the data of the PDO.
With
inhibit_time
, the minimum interval between
sending two PDOs can also be established in 100 µs
steps.
TPDOs
The use of all other values is not permitted.
Masking
transmit_mask_high and transmit_mask_low
If "change" is selected as the
transmission_type
, the TPDO is
always sent when at least 1 bit of the TPDO changes. But frequently
it is necessary that the TPDO should only be sent when
certain
bits
have changed. Therefore, the TPDO can be equipped with a mask:
Only the bits of the TPDO that are set to "1" in the mask are used
to evaluate whether the PDO has changed. Since this function is
manufacturer-specific, all bits of the masks are set as default value.
Summary of Contents for CMMP Series
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