Delta RMC101 - Manual (Page 468)

RMC100 and RMCWin User Manual
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Compact Mode without Sync
CAUTION: In this mode, the synchronization is left to be the PROFIBUS master’s responsibility. This is
very important to realize, because attempting to control the RMC over PROFIBUS in this sub-mode
from a PLC that asynchronously updates the PROFIBUS data will not work.
No additional synchronization registers are added to the two registers per axis. Instead, the RMC
processes a new command any time either output register for an axis changes. Two ways of
controlling the synchronization are to have the PLC either (1) enforce updating the PROFIBUS
data at the top of the scan (the SIMATIC TI505 can operate in this mode, but does not by
default), or (2) provide a function block for explicitly updating the PROFIBUS data (the SIMATIC
S7-300 series can use this option using the DPRD_DAT and DPWR_DAT system function
codes).
Once all commands have been processed and the data in the Input Registers has been updated,
the RMC100 copies the value from the Output Synchronization Register to the Input
Synchronization Register. This should be used as a cue for the Master control program to
process the data returned and/or issue the next commands.
See also:
Compact Mode Input Register Overview
Compact Mode Output Register Overview
Command Words for PROFIBUS-DP Compact Mode
Using the PROFIBUS-DP Message Mode
5.4.6.2 Compact Mode Input Register Overview
In addition to the Output registers, each RMC module requires two 16-bit registers per axis to
hold status information. The first input register for each axis always holds the current axis Status
word. The second input register can hold any of several values depending on the value of the
command register for the given axis.
When a Sensor DI/O module is installed, the state of inputs 0-17 and outputs 0-7 are reflected in
an additional two registers. The contents of these registers is given as follows:
First Sensor DI/O Input Register:
Bits 0-15 Sensor DI/O Inputs 0-15
Second Sensor DI/O Input Register:
Bits 0-1 Sensor DI/O Inputs 16-17
Bits 8-15 Sensor DI/O Outputs 0-7
If Compact Mode with Sync is used (versus Compact Mode without Sync), one additional 16-bit
register to hold the Synchronization Input is required. See Using the PROFIBUS-DP Compact