Hexagon Metrology, Inc.

Absolute Arm - 7 Axis SI

ROMER 7SI 2012 Overview-smThe universal scanning solution for all types of parts and applications.

The newly redesigned Romer Absolute Arm 7-Axis "SI" series with integrated laser scanner delivers the convenience of a fully integrated 3D scanning solution for a variety of applications. Use it for feature inspection to CAD, free-form surface inspection to CAD and reverse engineering. The scanner is incorporated into the seventh axis and rotates around the probe for a more natural feel. The SI version of the Absolute Arm is easily converted to an SE version to accept an externally mounted laser scanner.

Since its weight is balanced with ROMER's Zero-G counterbalance, the arm is the easiest and most ergonomic in the industry. The feature pack contains the scanner interface, so no external controller box is required. Single button automatic laser power control allows scanning of different surface types. No warm up time coupled with no homing procedures means an operator can be up and scanning in just minutes.

ROMER Absolute Arm with integrated scanner is the first portable arm system in the market that is factory calibrated and certified to B89 specifications.

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  1. Patented Infinite Rotation in the principle axes allows access to difficult to reach areas, while avoiding damaging the arm against rotational hard stops.
  2. Kinematic Probe Joint, the same type used in Hexagon Metrology bridge CMMs, provides repeatable connection of probes, with no need for recalibration. Automatic and repeatable probe recognition allows you to store hundreds of calibrated probe profiles for instant recall.
  3. Redesigned, ergonomic Pistol Grip handle increases operator comfort and productivity.  It is easy to hold, and is used to inspect parts or to interact with the software when in "mouse mode". Haptic feedback vibrates the wrist to alert the operator in noisy shop floor environments.
  4. Patented SpinGrips are infinitely rotating, low-friction "approved" hand hold positions for better user ergonomics. SpinGrips allow the arm to "float" in the operator's hands, reducing stress on the arm thus maximizing accuracy and repeatability while minimizing user fatigue.
  5. Absolute Encoders, super high-accuracy rotary encoders, designed specifically for Romer Absolute Arms, improve overall system accuracy while eliminating all complicated "homing" procedures.
  6. Aerospace grade Carbon Fiber Tubes provide a lightweight, stiff structure that is thermally stable. Under normal usage the carbon fiber tubes have a lifetime warranty.
  7. Low Profile Zero-G Counterbalance balances the arm's weight for easy, operation with effortless control, even above and below the arm's centerline. Better ergonomics means lower operator fatigue and better measuring results.
  8. Integrated handle and lifting point under counterbalance allow for easy carrying.
  9. Feature Packs plug into the base and provide interchangeable and upgradeable add-on capabilities such as WiFi connection, battery power, interface for laser scanners and more.
  10. Universal quick mounting base attaches to a variety of available base and stand options including magnetic bases.
  11. Fully integrated scanning solution – no additional cables or controller box
    • One button automatic laser power control – allows to scan on different surface types with minimal operator interaction
    • No warm-up time
    • Factory calibrated and certified scanning systems according to B89.4.22 (for Hexagon scanners only)
    • No coating or surface preparation necessary
    • Scanning and probing interchangeable, automated probe recognition
  12. Calibrated Length Standard – ROMER provides a NIST traceable calibrated length standard with each arm to allow the operator to easily verify and document system performance for ISO or vendor requirements.


The ROMER Absolute Arm Scanner 73 and 75 series offer two different levels of performance and features to suit most inspection requirements.

73-Series 75-Series
Absolute Encoders Included Included
Zero-G Counterbalance with Lock Included Included
SpinGrips N/A Included
TESA TKJ Connector Included Included
3 TESA Hard Probes Included Included
Integrated Scanner Included Included
Feature Pack ROMER Scanning Pack ROMER Scanning Pack
Digital Camera N/A N/A
LED Worklight N/A N/A
Certified Calibration Sphere Included Included
NIST Traceable Length Standard Bar Optional Included
Hard Case Included Included
Dust Cover Included Included
Base Bolt-down base plate Magnetic
Travel Case Included Included
Application Software

For Inspection:
For Reverse Engineering:

PC-DMIS Scanning
PC-DMIS Reshaper

PC-DMIS Scanning
PC-DMIS Reshaper
Utility Software RDS RDS
Factory Calibration and Certification according to B89.4.22* Included Included

*Hexagon Scanners only

Technical Specifications

7-Axis ROMER Absolute Arm with Integrated Scanner Probing and Scanning Specifications – 73 series

Model3 Measuring Range Probing
Point Repeatability1
Volumetric Accuracy2
System Accuracy4 (with RS3)
Arm Weights


2.0 m / 6.6 ft. ± 0.044 mm / 0.0017 in. ± 0.061 mm / 0.0024 in. ±0.0079 mm / 0.0031 in 8.3 kg / 18.3 lbs.


2.5 m / 8.2 ft. ± 0.049 mm / 0.0019 in. ± 0.069 mm / 0.0027 in. ±0.0084 mm / 0.0033 in. 8.6 kg / 19.0 lbs.


3.0 m / 9.8 ft. ± 0.079 mm / 0.0031 in. ± 0.100 mm / 0.0039 in. ±0.119 mm / 0.0047 in. 8.9 kg / 19.6 lbs.


3.5 m / 11.5 ft. ± 0.099 mm / 0.0039 in. ± 0.125 mm / 0.0049 in. ±0.147 mm / 0.0058 in. 9.2 kg / 20.3 lbs.


4.0 m / 13.1 ft. ± 0.115 mm / 0.0045 in. ± 0.151 mm / 0.0059 in. ±0.181 mm / 0.0071 in. 9.5 kg / 20.9 lbs.


4.5 m / 14.8 ft. ± 0.141 mm / 0.0056 in. ± 0.179 mm / 0.0070 in. ±0.214 mm / 0.0084 in. 9.8 kg / 21.6 lbs.

7-Axis Romer Absolute Arm with Integrated Scanner Probing and Scanning Specifications – 75 series

Model3 Measuring Range Probing
Point Repeatability1
Volumetric Accuracy2
System Accuracy4 (with RS3)
Arm Weights


2.0 m / 6.6 ft. ± 0.023 mm / 0.0009 in. ± 0.033 mm / 0.0013 in. ±0.058 mm / 0.0023 in. 8.6 kg / 19.0 lbs.


2.5 m / 8.2 ft. ± 0.027 mm / 0.0011 in. ± 0.038 mm / 0.0015 in. ±0.063 mm / 0.0025 in. 8.9 kg / 19.6 lbs.


3.0 m / 9.8 ft. ± 0.042 mm / 0.0017 in. ± 0.058 mm / 0.0023 in. ±0.083 mm / 0.0033 in. 9.2 kg / 20.3 lbs.


3.5 m / 11.5 ft.

± 0.055 mm / 0.0022 in.

± 0.081 mm / 0.0032 in.

±0.101 mm / 0.0040 in.

9.5 kg / 20.9 lbs.


4.0 m / 13.1 ft. ± 0.067 mm / 0.0026 in. ± 0.098 mm / 0.0039 in. ±0.119 mm / 0.0047 in. 9.8 kg / 21.6 lbs.


4.5 m / 14.8 ft. ± 0.084 mm / 0.0033 in. ± 0.119 mm / 0.0047 in. ±0.138 mm / 0.0054 in. 10.1 kg / 22.3 lbs.

All specifications according to B89.4.22.

1 The Point Repeatability Test is the reference test to determine measurement arm repeatability with ball probe. The cone is in front of the machine. Points are measured from multiple approach directions. The average point and the deviation of each point to the average center are calculated. The result is the maximum range divided by two.

2 The Volumetric Accuracy Test is the most representative test for volume measurement accuracy. A gage block with a known and certified length is measured several times throughout the working volume. This gage block is installed in different positions and measured depending on multiple approach directions. The result is the maximum deviation of the measuring distance less the theoretical length.

3 SI designates the ROMER Absolute Arm with integrated scanner.

4 The Scanning System Accuracy Test most accurately represents the reasonable expectations for machine performance in practical measuring applications while using the laser scanning method. The test consists of measuring a matte grey sphere with 5 different arm articulations. In each articulation of the arm the sphere is scanned from 5 different directions such that the majority of the sphere is scanned. The result is the maximum 3D center to center distance of the 5 spheres.

Ambient conditions:

  • Working temperature: 0°C - 50°C (32°F – 122°F)
  • Storage temperature: -30° -70° C (-22°F – 158°F)
  • Relative humidity: 10% - 90% non-condensing
  • Operational elevation: 0-2000 m (0-6600 ft)

Marks of conformity:

  • CE Compliance: Yes

Power requirement:

  • Universal worldwide voltage 110V-240V

ROMER Integrated Scanner Sensor Specifications


Integrated Scanner RS3
Max. Point acquisition rate 460,000 Points/s
Points per Line 4600
Line Rate 100 Hz
Line width

Min - 46 mm

Mid - 65 mm

Max - 85 mm

Stand off 150mm ± 50 mm / 5.8in ± 1.97in
Point spacing (min) 0.014 mm
Laser power control Fully-automatic – per line
Accuracy (2 sigma)1 30 µm / 0.0012 in
Weight 340 g /11.99 ounces
Controller No
Laser Safety Class 2M
Working temperature 5°C – 40°C (41°F – 104°F)

1 The sensor accuracy is defined as the deviation of the XY location of a calibration artifact through the measuring range of the sensor.

All probing specifications are achieved with a ROMER Absolute Arm mounted on a ROMER base plate or magnetic base and using a 15 mm steel ball probe with a length of 50 mm under stable environmental conditions.

All RS3 scanning specifications are achieved with a ROMER Absolute Arm mounted on a ROMER base plate or magnetic base and a matte grey calibration sphere of 25.4 mm diameter under stable environmental conditions.


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