SLIM Tach SL1250

SLIM Tach® SL1250 Incremental Encoder

 SLIM Tach SL1250
RIM Tach 1250

Quick Specs...

  • Mounts to NEMA 12.5 inch C face motor
  • Thin, compact, and occupies only 1.4 inches of motor shaft
  • Rugged, reliable, magnetoresistive technology
  • Easy installation with no brackets or couplings
  • Hard, anodized aluminum construction

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Overview Industry/Application Specifications Related Info  

Overview / Design Principle:

Employing NorthStar’s innovative magneto-resistive technology, this dependable product combines high accuracy with reliable service. Made of anodized aluminum and with a net thickness of only 1.4 inches, the SLIM Tach® SL1250 comes with one or two electrically independent and totally isolated output modules and a high temperature version for operation needs up to 120° C.

The SLIM Tach® S1250 assembly is imprinted with magnetic poles, providing higher pulse counts than traditional encoders. Its totally encapsulated electronics make it immune to machine vibration and contaminants. It is resistant to dirt, grease, water, oil, fibers, and dust, making it reliable in hot, wet environments. A high power line driver comes standard. Clean, crisp signals are ensured over long cable lengths, decreasing the need for signal repeaters and saving on total installation costs.

The SLIM Tach® 1250’s pulse wheels are available in thru-shaft sizes from 0.625 inch to 3.75 inches. The pulse wheels are keyless and very easy to align. The SL1250’s thin profile leaves plenty of room on the motor shaft for a brake or pulley and it mounts without bearings, adapter plates, or couplings, eliminating a common source of mechanical problems.

Features and Benefits:

  • Thru-shaft sizes from 0.625 to 3.75 inches
  • 64, 128, 256, 512, or 1024 pulses per revolution (PPR) with optional index pulse
  • 5-15VDC operation, bi-directional quadrature signals with high power, differential line driver outputs


NorthStar’s SLIM Tach® 1250 is an economical, bearingless, heavy duty encoder designed for 12.5 inch C face motors. Available with resolutions to 1024 PPR.

Standard Operating Characteristics
Code: Incremental
Pulses per Revolution: 60-2048
Phasing Sense: A leads B for Counter-Clockwise rotation (CCW) viewing encoder-mounted end
Quadrature Phasing: 90° ± 22°
Symmetry: 180° ± 54°
Index: 270° gated to falling B edge

Input Voltage Requirement: 5-15 or 5-26 Volts DC
Current Requirement: With Electrical Option L or H: 45 mA typical per sensor module plus line driver load
With Electrical Option V or 5: 65 mA typical per sensor module plus line driver load
Output Signals: With Elec Option L or H: 5-15 V Line Driver, 150mA
With Elec Option V: 5-26 V Line Driver, 100mA
With Elec Option 5: 5V Line Driver, 150mA
Frequency Response: 0 - 120kHz Data & Index
Electrical Immunity: 2kV ESD, Reverse Polarity, Short Circuit
Connector: 10 pin industrial duty latching, sealed NEMA 4 &12, IP65; MS connector or pig-tail

Shaft Speed: 5,000 RPM
Mounting Configuration: 12.5” C face mount for NEMA MG1-4 standards (excluding C-Face runout)
Housing Material: Cast Aluminum
Acceleration Rate: 12,000 rpm/sec max
Shaft Length Required: 1.1” min
Allowable Shaft End-Play: ± 0.045”
Allowable Shaft Runout: 0.003” TIR
Weight: 11 lbs.

Operating Temperature Range: Standard: -40°C to +90°C
Extended: -40°C to +120°C
Storage Temperature Range: -40°C to +120°C
Humidity: to 98% RH (non-condensing)
Shock (Sensor Module): 1 meter drop test, 30 G’s Min
Vibration: 18 G’s @ 5-2000 Hz spectrum

Available Specifications:

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