EMERSON DB1-1

Description

Product Description

The EMERSON DB1-1 is a discrete on-delay timer module designed for use within the iconic Emerson (formerly Gould Modicon) 584 and 984 series programmable logic controllers (PLCs). This physical function module provides reliable, hardwired timing logic that operates independently from the main processor’s scan cycle. The DB1-1 module is inserted into a dedicated slot in the PLC rack and functions by accepting a discrete input signal; upon energization, it initiates a predetermined time delay before energizing its output relay. This straightforward, robust design makes the EMERSON DB1-1 a trusted solution for adding dedicated timing functions to legacy control systems, offering an additional layer of reliability and simplicity for critical timing sequences where software timers may be deemed insufficient.

Product Parameters

• Function: On-Delay (Delay on Operate) Timer.
• Time Range: Typically adjustable via a dial or DIP switches on the front face, often covering multiple ranges (e.g., 0.1 to 10 seconds, 1 to 100 seconds). The specific range is model-dependent.
• Input Voltage: Designed to operate on the standard DC logic level supplied by the Emerson 584/984 PLC backplane (commonly 24V DC).
• Output Type: Discrete relay output (Form C or similar) capable of switching a load, with ratings typically around 2A at 24V DC or 120V AC.
• Mounting: Plugs directly into a designated I/O or function module slot in the compatible Emerson PLC rack.
• Indicators: Features LED status indicators for power, input activation, and output energization.

Advantages and Features

• Processor-Independent Operation: The EMERSON DB1-1 executes its timing function in hardware, unaffected by processor loading, scan time variations, or program changes. This guarantees deterministic timing performance.
• High Reliability & Simplicity: As a dedicated hardware module, it offers extreme reliability for critical timing functions. Its operation is simple to understand, troubleshoot, and validate.
• Legacy System Support: It is an essential spare part for maintaining and supporting the vast installed base of Emerson Modicon 584 and 984 PLC systems, which are still operational in many industries.
• Easy Configuration: Timing is set mechanically via a dial or switches, requiring no software programming for the timer function itself.
• Rugged Design: Built to withstand the electrical noise and environmental conditions of industrial settings common to its era.

Application Cases in Application Fields

• Manufacturing (Legacy Lines): Providing sequenced start-up delays for motors on old conveyor systems or stamping presses controlled by Emerson 984 PLCs.
• Water & Wastewater Treatment: Used in pump control panels to enforce minimum run times or off-delays between pump alternations in lift stations.
• Power Plant Auxiliary Systems: Controlling timing sequences for valve operations or fan interlocks in boiler feedwater or ash handling systems.
• Batch Processing: Creating simple, failsafe mix or cure time delays in older chemical or food processing equipment.

Comparisons with Competing Products

When compared to modern alternatives or other legacy timer modules:

• vs. Software Timers: Unlike a timer instruction in a modern PLC, the EMERSON DB1-1 is a dedicated hardware device. It does not use program memory or scan time, offering inherent failsafe characteristics that software cannot replicate if the processor faults.
• vs. Other Legacy Hardware Timers (e.g., Allen-Bradley Bulletin 700): The DB1-1 is specifically engineered for seamless integration into the Emerson/Modicon PLC rack system, drawing power and interfacing logically within that ecosystem. Stand-alone timers require separate mounting, wiring, and power supplies.
• vs. Newer PLCs: For modern systems, this functionality is entirely integrated into software. The DB1-1‘s value is almost exclusively in supporting and maintaining existing, legacy Emerson PLC installations where upgrading is not feasible.

Selection Suggestions and Precautions

• Selection Advice: The EMERSON DB1-1 should be selected specifically as a replacement part for an existing, failing module in an Emerson 584 or 984 PLC system. It is not a choice for new system designs. Verify the exact model and time range required by checking the label on the existing timer or the original system documentation.
• Precautions:
  1. System Compatibility: Confirm the specific Emerson/Modicon PLC model (e.g., 984-385, 584L) and rack type to ensure physical and electrical compatibility. Not all racks support all function modules.
  2. Time Range Verification: Ensure the selected DB1-1 module’s adjustable time range matches the application requirements of the control sequence it is part of.
  3. Configuration: Before installation, set the time delay dial or DIP switches to the required setting as per the control schematic or operational records.
  4. Obsolescence: This is a legacy component. Be cautious of surplus market sources and verify the functionality of the module prior to installation in a critical application.
  5. Modernization Planning: Reliance on the EMERSON DB1-1 indicates a legacy system. Consider procuring a strategic spare and simultaneously develop a long-term system modernization plan to mitigate eventual obsolescence risks.

EQ3700DW GE FCSDCS
G761-3039B GE
GK771K200A GE DCS
HFU640UY060J GE DCS
HFU640UY200J GE DCS
IS200TVBAH2ACC GE FCS