FBMSVH control module

The ASI module has one eight-position dipswitch to select the I/O module address on the I/O expander bus. This switch also selects built-in diagnostics for stand-alone testing.

The ASI module has two LED indicators, one red and one green, which show the operating status. 

The LEDs will: • Flash red on power-up. 

• Both LEDs will remain off after passing onboard diagnostics until the ASI module is configured by the controller.

 • Show solid green after the controlling controller downloads configuration data.

 • Show solid green during normal running. 

• Blink green when the controller that configured the ASI module enters configure mode from execute mode.

 • Blink green if I/O expander bus communication is lost (if the controller is removed). 

• Show solid red if a fatal failure of the ASI module occurs. For example, if power up diagnostics fail.

 • Show solid red for a power fail interrupt (PFI).

I/O Expander Bus

 The I/O expander bus is a high-speed, synchronous, parallel bus. It provides a path between controllers and I/O modules. The controller sends control functions to the ASI module, and the ASI module provides input data to the controller. The P2 card edge of the ASI module and controller connect to the bus. The I/O expander bus is parallel signal lines located on the module mounting unit backplane. A 12-position dipshunt placed in a socket on the MMU backplane connects the bus between the controller and I/O modules. Cable assemblies can extend the bus to eight module mounting units. A controller and its I/O modules form a subsystem within a Harmony control unit (HCU). The I/O expander bus between control and I/O subsystems must be separated. Leaving a dipshunt socket empty or not connecting the module mounting units with cables separates them.

Termination Units

 The IMASI13 module uses one NTAI06 termination unit to connect to field signals. An NKAS01 or NKAS11 cable connects the termination unit to the ASI module through its P3 connector. The termination unit contains RTDs used for cold junction compensation of thermocouple inputs. They also contain the circuitry needed to convert 4 to 20 milliampere field signals 2 - 6 WBPEEUI240766B0 Automatic Adjustments and Corrections into the 1 to 5 VDC needed to input to the analog input module. The system power supply is protected from short circuits by fuses on the NTAI06 termination unit.