Appendix A. Performance Data
280
PACSystems* RX7i, RX3i and RSTi-EP CPU Reference Manual
GFK-2222AD
A-3.4
I/O Scan and I/O Fault Sweep Impact
The I/O scan sweep impact has two parts, Local I/O and Genius I/O. The equation for computing I/O scan
sweep impact is:
=
+
Genius I/O Scan
Impact
I/O Scan Sweep Impact
Local Scan Impact
Sweep Impact of Local I/O Modules
The I/O scan of I/O modules is impacted as much by location and reference address of a module as it is
by the number of modules. The I/O scan has several basic parts.
I/O Scan
Description
Rack Setup Time
Each expansion rack is selected separately because of the addressing of
expansion racks on the VME bus. This results in a fixed overhead per
expansion rack, regardless of the number of modules in that rack.
Per Module Setup Time Each Local I/O module has a fixed setup scan time.
Byte Transfer Time
The actual transfer of bytes is much faster for modules located in the main
rack than for those in expansion racks. The byte transfer time differences will
be accounted for by using different times for I/O modules in the main rack
versus expansion racks.
In addition, analog input expander modules (the same as Genius blocks) have the ability to be grouped
into a single transfer as long as consecutive reference addresses are used for modules that have
consecutive slot addresses. Each sequence of consecutively addressed modules is called a scan segment.
There is a time penalty for each additional scan segment.
RX7i I/O Module Types
Type
Part Numbers
Discrete Input Type I
(16-point, 14-point)
IC697MDL240, IC697MDL241, IC697MDL251, IC697MDL640,
IC697MDL671
Discrete Input Type II
(32-point)
IC697MDL250, IC697MDL252, IC697MDL253, IC697MDL254,
IC697MDL651, IC697MDL652, IC697MDL653, IC697MDL650,
IC697MDL654
Discrete Output Type I
(16-point, 12-point)
IC697MDL340, IC697MDL341, IC697MDL740, IC697MDL940
Discrete Output Type II
(32-point)
IC697MDL350, IC697MDL750, IC697MDL752, IC697MDL753
Analog Input Type I
(8-Channel)
IC697ALG230
Analog Input Type II
(16-Channel with 8-channel AI
module)
IC697ALG440, IC697ALG441
Analog Output
(4-channel)
IC697ALG320
