Programming the MOBY-ASM on PROFIBUS
B.3 Methods of operation with the ASM
FC 45
B-10
Function manual, Release 03/2006 , J31069-D0167-U001-A2-7618
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If the PROFIBUS master can be set to permit several non-cyclic telegrams between cyclic
data communication, PROFIBUS data transmission can be accelerated in a bus
configuration with many MOBY-ASMs. However, this has a negative effect on the cyclic
data communication of I/O modules which are also part of the same PROFIBUS branch.
The cycle time of PROFIBUS becomes irregular and sporadically may become very high.
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When more commands are to be processed by the ASM than ASM buffer space, the user
must first fetch results from the ASM before new commands can be sent to the ASM.
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The ASM does not absolutely require the chaining bit in the command. However, from the
user's point of view, it is an elegant way to identify related partial commands. A chaining
bit which is set in the command is returned by the ASM in the acknowledgment.
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The number of buffers on the ASM varies with the type of ASM. For more information,
see Section "Command repetition".