ABB DX531, article 1SAP245000R0001, is an S500 digital input/output module with eight two-wire 120/230 V AC inputs and four relay outputs. It is intended for applications where high-voltage sensing and relay switching must share one plug-in module.

• Detects eight 120/230 V AC field signals through the documented two-wire input circuits.
• Switches four independent loads through changeover relay contacts.
• Displays input and relay-output states locally for commissioning and maintenance checks.
• Separates the plug-in electronics from permanent field wiring through the S500 terminal-unit concept.
• Combines sensing and switching for high-voltage control circuits in one station position.

• Monitoring mains-voltage limit switches, auxiliary contacts and field status signals.
• Switching contactors, alarms or interposing circuits within the documented relay ratings.
• S500 stations that require eight AC inputs and four relay outputs at one module position.
• Maintenance replacement for article 1SAP245000R0001 with the existing TU531 or TU532 terminal unit.
• Machine and process panels where two-wire AC input behavior must be retained.

• ABB lists DX531 article 1SAP245000R0001 in the Active lifecycle phase.
• Keep the installed input voltage, two-wire circuit design and relay-contact allocation in the asset record.
• Do not substitute DX522: it uses 24 V DC inputs and provides eight rather than four relay outputs.
• Confirm the terminal-unit type and field-voltage segregation before maintenance.
• Test all eight AC inputs and four changeover relay paths after exchange.