ABB ASE2UDC920AE01 3BHB022793R0001 Digital Module

Channel Electrical Isolation: Optoelectronic isolation technology (isolation voltage: 500V AC) is adopted between DI/DO channels, module power supply, and the system bus. This prevents strong on-site electrical signals (e.g., surge from motor start-stop) from intruding into the system bus and damaging the main control unit.

Signal Debouncing: Software debouncing is applied to the switch signals input via DI channels (debounce time: 1ms–100ms adjustable). For example, when the contacts of a limit switch jitter, the module ignores signal fluctuations shorter than the set debounce time to avoid false triggering of control commands.

Relay Output Protection: The relays of DO channels adopt a "break-before-make" switching logic (SPDT contacts) to prevent two output circuits from being energized simultaneously during load switching. It also supports a "forced output" function (configurable via UDC 920 software), allowing manual forced output of specific states (e.g., emergency opening of safety valves) in case of module failure.

DI Channels: Set input type (dry contact/wet contact), debounce time, and signal polarity (high-level active/low-level active).

DO Channels: Set output mode (normally energized/normally de-energized) and fail-safe state (output "on" or "off" when the module is powered off, e.g., closing fuel valves during power outage).

Interlock Logic: Configure direct interlocks between DI and DO channels (e.g., a "high pressure" DI signal triggers a "pump shutdown" DO output). This does not rely on the main control unit, reducing response delay.

Hardware Diagnostics: Real-time monitoring of module power voltage (alerts when voltage is below 18V or above 30V), relay contact status (outputs fault signal if contacts stick), and communication bus connection (red fault light illuminates in case of bus interruption).

Software Diagnostics: The UDC 920 main control unit can read module status words (e.g., "channel fault code," "communication error count") and support remote fault reset (no on-site operation required).

Safety Interlock Function: Complies with the IEC 61508 SIL 2 safety standard and can serve as an input/output unit for safety loops (e.g., emergency shutdown loops of chemical plants). DI channels support "dual-channel redundant acquisition" (two channels acquire the same signal, and validity is confirmed only if the two signals match). DO channels support "dual-output drive" (two outputs control the same actuator to ensure reliable execution of commands).

Hot-Swapping Support: In the UDC 920 system’s "module offline" mode, the module can be hot-swapped (a dedicated tool is required). The replacement process does not affect the operation of other modules, reducing system downtime (suitable for continuous production scenarios such as oil refineries and power plants).

Parameter Backup and Restoration: Module configuration parameters are stored in non-volatile memory (EEPROM) and will not be lost after power outage. Parameters can be backed up via UDC 920 software and quickly imported to a new module after replacement, eliminating the need for reconfiguration.