The **XHS35F-50-R2-FS-XPROGAB** is a high-performance industrial incremental encoder manufactured by **BEI Sensors** (now part of Sensata Technologies). It is specifically designed for hollow-shaft mounting in heavy-duty environments. ### 1. Part Number Breakdown (Specifications) Understanding the alphanumeric code reveals the core electronic and mechanical characteristics: | Code Segment | Feature | Description | | :--- | :--- | :--- | | **XHS35** | Series | Heavy Duty, Explosion Proof / Hazardous Area Rated Encoder. | | **F** | Mounting | Hollow Shaft style (usually 1-inch or 3/8-inch bore). | | **50** | Resolution | 50 Pulses Per Revolution (PPR). | | **R2** | Output Type | Differential Line Driver (RS422 compatible). | | **FS** | Connection | Field Selectable / Standard Connector or Cable. | | **XPROGAB** | Special Options | Specific internal programming or housing features for hazardous locations. | --- ### 2. Electronic Components and Interface The internal electronics of this unit are designed for signal integrity over long distances and resistance to electrical noise. #### A. Sensing Technology The unit uses **Optical Sensing**. A light source (LED) shines through a rotating disk with 50 etched slits. A photodetector converts the light pulses into electrical square waves. #### B. Output Signals (R2 Line Driver) The "R2" designation indicates a **Differential Line Driver** (typically 5-28V DC). * **Channels:** Provides A, B, and Z (Index) signals. * **Complementary Signals:** It also provides $\bar{A}$, $\bar{B}$, and $\bar{Z}$. * **Benefit:** Differential signaling cancels out Electromagnetic Interference (EMI), allowing the encoder to operate near large motors or high-voltage lines. #### C. Electrical Protections * **Reverse Polarity:** Prevents damage if the power supply wires are accidentally swapped. * **Short Circuit Protection:** Protects the output drivers if the signal wires touch ground or each other. * **ESD Protection:** Shielded against static discharge common in industrial handling. --- ### 3. Mechanical & Environmental Specifications | Feature | Specification | | :--- | :--- | | **Supply Voltage** | 5V to 28V DC | | **Bore Size** | Typically 1.0" with insulating inserts available. | | **Housing Material** | Anodized Aluminum or Stainless Steel. | | **Sealing** | IP65 or IP67 (Dust tight and water resistant). | | **Hazardous Rating** | ATEX/IECEx certified for Zone 1 or Zone 2 (depending on specific XPROG sub-type). | --- ### 4. Typical Applications The XHS35F series is most commonly found in: * **Oil & Gas:** Drawworks and top drive speed feedback. * **Mining:** Conveyor belt synchronization in explosive dust environments. * **Large Motors:** Speed control for VFD-driven AC/DC motors in harsh mills.