GE PACSystems RX7i Reference Manual page 296

Sweep Impact of Genius I/O and GBCs
For the sweep impact of Genius I/O and Genius Bus Controllers (GBC), there is a sweep impact for each
GBC, a sweep impact for each scan segment, and a transfer time (per word) sweep impact for all I/O data.
The GBC sweep impact has three parts:
1. Sweep impact to open the System Communications Window. This is added only once when the
first intelligent option module (of which the GBC is one) is placed in the system.
2. Sweep impact to poll each GBC for background messages (datagrams). This part is an impact for
every GBC in the system.
Note: Both the first and second parts of the GBC's sweep impact may be eliminated by closing the
Backplane Communications Window (setting its time to 0). This should only be done to
reduce scan time during critical phases of a process to ensure minimal scan time. Incoming
messages will timeout and COMM_REQs will stop working while the window is closed.
3. Sweep impact to scan the GBC. This results from the CPU notifying the GBC that its new output
data has been transferred, commanding the GBC to ready its input data, and informing the GBC
that the CPU has finished another sweep and is still in RUN Mode.
A scan segment for a Genius I/O block consists of consecutive memory locations starting from a
particular reference address. A new scan segment is created for each starting input or output reference
address. The time to process a single scan segment is higher for an input scan segment than it is for an
output scan segment. The scan segment processing is the same for analog, discrete, and global data scan
segments. Discrete data is transferred a byte at a time and takes longer to complete the transfer than
analog data, which is transferred a word at a time. Global data should be counted as either discrete or
analog, based on the memory references used in the source or destination.
Sweep Impact Time of Genius I/O and GBCs
Note: Functions in bold type impact the sweep continuously. All other functions impact the sweep
only when invoked. Not all the timing information listed in the following table was available
at print time for this manual (the blank spaces).
Genius Bus Controller
open backplane communications window
per Genius Bus Controller polling for background
messages
per Genius Bus Controller I/O Scan
Genius Bus Controller in the main rack
Genius Bus Controller in the expansion rack
Genius I/O Blocks
per I/O block scan segment
per I/O block scan segment w/point faults enabled
per byte discrete I/O data in the main rack
per byte discrete I/O data in expansion racks
per word analog I/O data in the main rack
per word analog I/O data in expansion racks
GFK-2222AD
CPU310
(µs)
30.0
403.0
469.0
683.0
3.0
3.0
13.0
16.0
24.0
34.0
April 2018
Appendix A. Performance Data
CPE010 CPE020 CPE030
(µs) (µs) (µs)
24.0 4.0
19.0 11.0
1.0 1.0
11.0 7.0
217.0 217.0 193.7
217.0 217.0 194.8
3.0 3.0
8.0 5.0
5.0 4.0
11.0 8.0
CPE040
(µs)
4.0 1.0
9.0 6.0
1.0 1.0
6.9 1.0
208.0
213.0
2.1 3.0
4.2 4.0
4.0 5.0
8.0 11.0
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