Chapter 4. CPU Operation
PACSystems* RX7i & RX3i CPU Reference Manual
The Genius Bus Controller (GBC) controls a single Genius I/O bus. Any type of Genius I/O device may
be attached to the bus.
In the I/O Fault Table, the rack, slot, bus, module, and I/O point number are given for a fault. Refer to
PACSystems RX7i and RX3i CPU Programmer’s Reference Manual, GFK-2950 Chapter 9 for decoding.
In non-redundant systems, bus #1 refers to the bus on the single-channel GBC. In redundant
systems, bus number is represented as either #1 or #2.
Genius I/O Configuration
The programming software can configure a subset of the parameters associated with Genius I/O
Genius I/O blocks have a number of parameters that can be set using the Genius I/O Hand-Held
Monitor. These parameter values are stored in EEPROM in the block itself. The serial bus address (SBA)
and baud rate must be set using the Genius I/O Hand-Held Monitor. For specific information on
Genius I/O block types, configuration, and setup, refer to the Genius I/O System User’s Manuals,
GEK-90486-1 and GEK-90486-2.
Through the COMMREQ function block, the application program can request the GBC to change any
default condition on a specific block. However, the block only accepts this change if it is not in Config
Protect mode. If Config Protect mode is set, only the Hand-Held Monitor can be used to change the
defaults. The format of the COMMREQ function block for Genius I/O is described in the Series 90-70
Genius Bus Controller User’s Manual, GFK-2017 and the Series 90-30 Genius Bus Controller User’s
Genius I/O Data Mapping
Genius I/O discrete inputs and outputs are stored as bits in the CPU Bit Cache memory. Genius I/O
analog data is stored in the application RAM allocated for that purpose (%AI and %AQ). Analog data
is always stored one channel per one word (16 bit).
An analog grouped module consumes (in the input and output data memories) only the amount of
data space required for the actual inputs and outputs. For example, the Genius I/O 115 Vac Grouped
Analog Block, IC660CBA100, has four inputs and two outputs. It consumes four words of Analog Input
memory (%AI) and two words of Analog Output memory.
A discrete grouped module, each point of which is configurable with the Hand-Held Monitor (HHM) to
be input, output, or output with feedback, consumes an amount in both discrete input memory (%I)
and discrete output memory (%Q) equal to its physical size. Therefore, the eight-point Discrete
Grouped Block (IC660CBD100) requires eight bits in the %I memory and eight bits in the %Q memory,
regardless of how each point on the block is configured.
Analog Grouped Block
The six-channel Analog Grouped block contains four analog input channels and two analog output
channels. When this block gets its turn on the Genius I/O Bus, it broadcasts the data for all four input
channels in one broadcast control message. Then, when the GBC gets its turn, it sends the data for
both output channels to the block in a directed control message.
Low-Level Analog Blocks
Unlike the Analog Grouped block, the low-level analog blocks, such as the Thermocouple and RTD
blocks, are input-only blocks. All have six channels.