• About
  • Summary
  • System Specification
  • Measurement Specification

KMS 306 (PMR) Media Testing

Kerr Mapping System 306 (KMS 306) provides a mapping of the magnetic properties (Hc, Hk, Hs, Hn, Hn', and SR) of the Perpendicular Magnetic Recording (PMR) mediaat any point of the entire disk in accordance to the user's setting or at any predefined position and plots a full hysteresis loop within secods.

The system is fully automated and capable of high-throughput quality control testing of magnetic disk media. The system can handle an entire standard 25-disk cassette and disk of 4 different sizes (65mm, 48mm, 27.4mm & 21.6mm). Users can customized the test sequence through the system's operating software to suit their testing needs.

The system is equipped with user-friendly graphic interfaces which provide flexibility to usage by different user groups such as operators, technicians and engineers.

  • High magnetic field up to 18,000 Oersteds and above
  • 2 to 100 seconds programmable sweep rate
  • High magnetic field resolution
  • Auto Field Feedback ensure constant dH/dt
  • Measurement of Hc, Hk, Hs, Hn, Hn' & SR of disk media
  • Non-destructive, non-contact measurement
  • Measures up to 4 different meadia disk sizes
  • Rapid mapping and High accuracy to provide fast process feedback
  • User programmable location and Maps for Measurement
  • Re-checks same measurement point without losing disk datum and position
  • In the near future, Blue laser Diodes would be used


Size (in mm)
1273W x 813D x 1717H
Weight (in KG) :

Operating Environment Requirements

Operating Environment
Cleanroom Class 1,000 or better
Temperature Range :
20°C ± 2°C (68°F ± 3.6°F)
Relative Humidity :
70% and below, Non-condensing

Electrical Requirements

Input Voltage
230VAC, 10A, Single Phase, 3-wire configuration
Frequency :
Input Connection :
3-meter line cord with 208VAC, 8A BS1363 plug

Air Input Requirements

High Pressure Air (HPA)
Clean, dry air at 0.45 ± 0.03 MPa
Incoming Air Inlet :
Ø6mm tubing
Disk Vaccum Setting :

Measurement Specification

Positioning System
Ball screw assist nano-step stepping motor
Disk Holding Chuck
Air pneumatic actuated
Magnetic Properties Measurable
Coercivity (Hc), Squareness Ratio (SR), Hn, Hn', Hs & Hk
H, Field Strength Range
24,000 Gauss Max

Measurement Duration (Sweep Rate)


Min. 2sec, max. 100sec

(1 sec is possible but not recommended)
2,000 to 7,000 Oe
± 0.5%
15 Oe
SR :
0.50 to 0.98
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©2007 Seidensha Singapore Pte. Ltd.
Last Updated May 2010