ELAU PacDrive M, Operating Manual, Page: 45 / 88

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PacDrive™ M field bus PROFIBUS-DP page 45
6.3 PROFIBUS-DP Master
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Table 6-8: Sensible combinations of DataExMode and IOTrigger
BusEnable
Used to block the automatic Profibus start in cyclic operation after
switching on or resetting MAx4. The bus is blocked if this parameter
is set to FALSE in the MAx4 boot procedure. Now the parameter
can be set to TRUE at any position in the IEC program. As soon as
this happens, Profibus will enter into cyclic operation. Any
subsequent change of this parameter will have no effect. If the
parameter is TRUE at the point of booting, Profibus is switched to
cyclic operation in the booting phase. In this case any change of
this parameter will have no effect.
IRQ
The interrupt chosen in the interrupt jumper setting on the Profibus
hardware must be entered here. You should always use interrupt 7
or 9.
sync. buffered
firmware
access to PB
data / 1 IO matching by
IEC program /
2 IEC control active; i.e. the IEC function
PrMaTrigger is used-> IEC program triggers
IO match. After the IO match the Profibus is
triggered, i.e. a Profibus cycle is started.
+ minimal average jitter; data consistency;
no influence on Profibus cycle
- complex
See also PROFIBUS-DP libraries / IEC
examples in the EPAS-4 online help.
IEC control active / asynchronous; as
above. In addition, the IEC function
PrMaGetServerState() is used.
+ consistent data can be reached even in
case of an IEC task priority greater than the
priority of the IO server.
See also PROFIBUS-DP libraries / IEC
examples in the EPAS-4 online help.
sync. direct
firmware
access to PB
data with cycle
control / 2 IO matching by
field bus card
IRQ / 1 no IEC control; i.e. no IEC function is used
+ very easy handling
- relatively large jitter
sync. direct
firmware
access to PB
data with cycle
control / 2 IO matching by
field bus card
IRQ / 1 IEC control passive; i.e. the IEC function
PrMaWaitOnTrigger is used-> awaiting for
IRQ of the field bus card
+ minimal jitter
- unfavorable in cyclic programs, due to
waiting function
See also PROFIBUS-DP libraries / IEC
examples in the EPAS-4 online help.
DataExMode IOTrigger Explanations