Rockwell Automation 1746-NO8V SLC 500 8-Point Analog Output Module/ User Manual - Manual (Page 23)

Publication 1746-UM026A-EN-P - September 2003
Preliminary Operating Considerations 3-3
How the SLC Processor
Communicates with the
Module The SLC processor transfers data to (and receives data from) the
output module through an image table residing in the data files of the
SLC processor. The processor updates this image table once during
each scan of the ladder program. Figure 4 shows the image table for
your output module.
Figure 3.1 Output and input scans
Channel Update Time For an output module, channel update time is the time required for
the module to convert the channel data received from the processor to
an analog output signal at the terminals.
The channel update time varies depending upon mode of operation
and features implemented. Class 1 and Class 3 update times are
shown below:
SLC 500
Data Files Module
Image Table
Slot e
Input Image
Slot e
Output Image
Output Image:
8 words Class 1
32 words Class 3
Input Image:
8 words Class 1
16 words Class 3
Table 3.3 1746-NO8 Channel Update Time (all channels)
Mode of Operation Update Time
Class 1 5 ms
Class 3 10 ms