ABB Bailey IIMKM01A Multibus Keyboard Module

Technical Specifications

Parameter	Value
Brand	ABB Bailey
Model	IIMKM01A
Category	Multibus Keyboard Module
Weight	0.62 lbs (0.28 kg)
Dimensions	5.3 x 4.1 x 1.2 inches
Component Count	94 discrete components
Bus Interface	Multibus I (IEEE 796)
Key Matrix Support	8 x 8 (64 keys maximum)
Scan Rate	10 ms per full scan
Debounce Time	5 ms programmable
Key Detection	Active low, pull-up resistors
Output Format	8-bit scan code
Interrupt Support	Yes, programmable
Onboard Memory	128 bytes FIFO buffer
Operating Voltage	5V DC from backplane
Current Draw	85 mA from 5V bus
Energy Storage	2 x 47µF, 4 x 10µF
Connector Type	20-pin ribbon cable
Temperature Range	0°C to 55°C

Physical Construction and Component Layout

This IIMKM01A Multibus keyboard module measures 5.3 inches in length. Its width reaches 4.1 inches with a thickness of 1.2 inches. The total weight comes to approximately 0.62 pounds. Manufacturers placed 94 discrete components on this compact PCB. These components include a keyboard controller, FIFO buffer, decoders, and pull-up resistors. The board uses a four-layer design for signal integrity.

Keyboard Interface and Key Detection

IIMKM01A supports up to 64 keys in an 8 x 8 matrix arrangement. The module scans the entire key matrix every 10 milliseconds. Programmable debounce time eliminates false readings from mechanical switches. The debounce setting typically uses 5 milliseconds for most applications. Key detection uses active-low logic with internal pull-up resistors. Each key press generates an 8-bit scan code for identification. A 128-byte FIFO buffer stores key presses during busy periods. Consequently, the system never misses rapid keystroke sequences.

Bus Compatibility and Interrupt Features

The keyboard module interfaces directly with the Multibus I backplane. This bus follows the IEEE 796 standard for industrial systems. The IIMKM01A can generate interrupts on key presses. You can program the interrupt behavior through software configuration. The module outputs scan codes for the processor to interpret. Status LEDs indicate power, data activity, and buffer status.

Energy Storage and Application Use

IIMKM01A integrates two 47µF capacitors for bulk energy storage. Four additional 10µF capacitors filter high-frequency power noise. The module draws only 85 milliamps from the 5V DC backplane. You will use this module in Bailey Multibus industrial computer systems. It connects to membrane keypads or full keyboard assemblies. The IIMKM01A operates reliably from 0°C to 55°C ambient. For example, it provides operator input for CNC controls or process stations. Therefore, this keyboard module delivers reliable human-machine interface for ABB Bailey systems.