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Serial Interface to I/O Slot
6.2 Serial Interface to I/O Slot
The following plug-in modules for CPU module slots 0 allow CPU extension with
additional communications interfaces.
6.2.1 General Comments about the Plug-In Module PCD2.F2xxx
System properties of PCD2.F2xxx modules:
The following points must be taken into consideration when using PCD2.F2xxx
interface modules.
● For each PCD1 system, one PCD2.F2xxx module (with 2 interfaces) can be
used per I/O slot. This makes a total of 4 additional interfaces.
● The PCD1.M2_ system has a powerful processor, which handles the application
as well as the serial interfaces. Interface module processing demands an
appropriate amount of CPU power. To determine the maximum communications
performance per PCD1.M2_ system, the following must be considered.
● The volume of communication is determined by the connected peripheral
devices. This is the case, for example, if a PCD1 is used as an S-Bus slave
station.IfaPCD2controllerisbombardedwithheavytelegramtracathigh
baud rates, less CPU power is available to handle of the actual application. The
following rules apply:
- The use of 6 interfaces with 9.6 kbps take approx. 50% of CPU power.
- Two interfaces with 57.6 kbps take approx. 50% of CPU power.
- Two interfaces with 115 kbps take approx. 60% of CPU power.
● If the PCD1 is the communications master (PCD1 used as master station),
the PCD1’s user program will determine the volume of communication and
therefore also its power. Theoretically, all interfaces can be operated with a
maximumbaudrateof115kbps.Theeectivedatadeliveryrateisreducedby
the size of the user program and the number of active interfaces. It is essential
to ensure that connected peripheral devices can operate with the selected
congurationandcommunicationspower..
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