Description
The Siemens Milltronics RBSS (7MH7134-2AB30) is a high-resolution, wheel-driven return belt speed sensor. It tracks the mechanical travel speed of bulk material conveyor belts and transmits digital pulse frequency telemetry directly to instrumentation integrators (such as the Milltronics BW500) or PLC weigh-feeing systems (such as the Siemens SIWAREX FTC) to calculate totalized material flow rates.
Commercial and Logistics Details
- Product Condition: New Original (Factory Sealed)
- Warranty Period: 12 Months
- Standard Lead Time: 2–5 business days from order confirmation
- Pricing Note: Price varies depending on targeted material options and localized project scope; contact our application engineering group for a firm, formal quote.
Technical Architecture & Field Deployment Notes
In aggregate mining, cement handling, and heavy mineral processing applications, tracking actual belt speed rather than motor shaft speed is essential to account for physical belt slippage under heavy loads. The 7MH7134-2AB30 addresses this by interfacing directly with the clean side of the return belt profile.
Mechanical Action & Pulse Generation
The assembly uses a dynamic trailing arm structure housing a 5-inch diameter polyurethane tread sensor wheel. As the return belt drives this wheel, a 60-toothed internal speed sprocket rotates past an integrated magnetic sensor. This design generates an precise output frequency profile equivalent to 60 pulses per revolution, or 150.4 pulses per meter (4.58 pulses per foot) of linear belt travel.
Field Installation Guidelines
- Mounting Position: Install the unit’s crossbar between structural conveyor stringers immediately before or after a return belt idler frame. The natural weight of the trailing arm ensures the polyurethane wheel maintains continuous traction without slipping against the moving belt surface.
- Electrical Interfacing: The sensor outputs an NPN open collector sinking signal. When running extensive cabling distances back to the main control enclosure, utilize high-quality shielded 3-conductor 22 AWG wire to suppress transient induced voltage from nearby high-power conveyor drive motors.
Technical Specifications
| Parameter | Value |
| Brand | Siemens (Milltronics) |
| Model Number | RBSS |
| Part Number | 7MH7134-2AB30 |
| Operating Input Speed | 2 to 450 rpm |
| Output Resolution | 60 pulses per revolution (150.4 pulses/m) |
| Output Driver Configuration | NPN open collector sinking |
| Input Supply Voltage | 4.5 to 28 V DC (16 mA nominal draw) |
| Enclosure Fabrication | Standard polyester painted mild steel (C5-M rated) |
| Sensor Wheel Construction | Polyurethane tread, 5-inch diameter |
| Integral Cable Specification | 3 meters (10 ft), 3-conductor 22 AWG |
| System Ingress Protection | IP67 rated |
| Regulatory Compliances | CE, UKCA, RCM, EAC, KC |
| Net Shipping Weight | 16.5 kg (36.4 lbs) |
Frequently Asked Questions
Does this specific part number require an external switch isolator?
No. The 7MH7134-2AB30 is the standard fabrication model and does not require a specialized external switch isolator barrier for standard electrical installations. If your site plan dictates deployment within hazardous environments containing explosive dust or gases, verify configuration details for intrinsically safe models (such as ATEX II 1G zones) with the OEM datasheet.
What maintenance steps are recommended for high-dust mining environments?
Regularly inspect the polyurethane wheel tread for material build-up or irregular flat spots, which alter the effective tracking diameter and distort weighing accuracy. Additionally, verify that the pivot pin on the steel trailing arm moves freely so the wheel’s weight can consistently track any vertical bouncing of the conveyor belt.
Can I connect this sensor directly to a generic PLC high-speed counter card?
Yes. Because the output signal uses a standard NPN open collector sinking architecture, it can wire directly into standard 24 V DC PLC digital inputs or specialized high-speed counter modules (e.g., SIMATIC S7 ET 200SP TM Count modules). Ensure the input card pull-up resistor parameters match the sensor’s voltage constraints.
