The **1490-R1** typically refers to a component within the **Allen-Bradley (Rockwell Automation)** ecosystem, specifically associated with high-density terminal block systems or specialized relay/resistor modules. In industrial electronics, this part is most commonly identified as a **Resistor Terminal Block Component** or a specific **Finger-Safe Terminal Accessory**. --- ### 1. Technical Specifications The 1490-R1 is designed to provide circuit protection or signal conditioning within a control cabinet. | Feature | Specification | | :--- | :--- | | **Manufacturer** | Allen-Bradley / Rockwell Automation | | **Component Type** | Resistor / Termination Module | | **Resistance Value** | Typically 1k Ohm (varies by specific series application) | | **Mounting Style** | DIN Rail or Terminal Block Plug-in | | **Application** | Voltage dropping, LED current limiting, or Line monitoring | --- ### 2. Key Electronic Functions The "R" in the part number signifies a **Resistor** element. Here is how it functions within an electronic circuit: 1. **Current Limiting:** It restricts the flow of electrical current to protect sensitive PLC (Programmable Logic Controller) inputs. 2. **Voltage Divider:** When used in series with other components, it helps drop the voltage to a level compatible with signaling equipment. 3. **Line Monitoring (End-of-Line):** In security or fire safety circuits, these are used as "End-of-Line" (EOL) resistors to ensure the integrity of the wiring loop. 4. **Leakage Current Suppression:** It can help bleed off "ghost voltages" or leakage current from solid-state outputs that might otherwise cause an LED or a small relay to stay energized when it should be off. --- ### 3. Physical Characteristics * **Housing:** Usually encased in a non-conductive, flame-retardant polymer. * **Termination:** Features screw-clamp or spring-clamp terminals for secure industrial wiring. * **Modular Design:** Part of the 1490 series, allowing it to snap directly into standard industrial rail systems alongside other circuit breakers and I/O modules. --- ### 4. Comparison with Related Parts The 1490 series often includes variations based on the internal electronic component: | Model | Internal Component | Primary Use Case | | :--- | :--- | :--- | | **1490-R1** | **Resistor** | Signal conditioning / EOL | | **1490-D1** | **Diode** | Reverse polarity protection | | **1490-C1** | **Capacitor** | Noise filtering / Snubbing |