Reading the Configuration

At the end of the application download, the CPU configures all modules on the local rack. The CPU’s Ethernet I/O scanner service reads from the CPU memory to get the configuration of the RIO drops declared in the Control Expert configuration. The configuration of the RIO drops is used to configure the FDR server in the CPU.

At power up, each BM•CRA312•0 X80 EIO adapter module gets an IP address from the CPU’s DHCP server. Then it reads its configuration from the FDR server in the CPU. Finally, the CPU’s Ethernet I/O scanner service initializes the configured I/O modules in the rack.

NOTE: Verify that the IP address on each piece of distributed equipment is correct and unique before initial start.
NOTE: If the BM•CRA312•0 module is powered up first, the IP address is derived from the MAC address printed on the front of the module. The adapter module then performs checks to see if a DHCP server becomes available to distribute an IP address.

The RUN Command

Before receiving a RUN command from the CPU, all RIO drops are configured and connected to the CPU with Ethernet I/O scanner service. The RUN LEDs on the BM•CRA312•0 modules blink to indicate that the CPU is in the STOP state. In the RIO drops, the physical outputs remain in the fallback state (output forced to 0). Input values in the CPU memory image are interpreted as 0.

When the CPU is in RUN state, RIO drops change from the STOP to the RUN state. The LEDs on the BM•CRA312•0 module indicate this change. Output data received from the CPU are applied to physical outputs. Input images in the CPU are updated with physical inputs.

NOTE: For local I/O in the CPU or extended rack and for Premium I/O, there is no change in the comparison with previous versions of CPUs.