10.2 Technical Information

10.2 MINISCALE PLUS Technical Information

10.2.1 MINISCALE PLUS Performance Parameters

10.2.2 Dimension Tables, Load Capacities and Torque Loads for Standard MINISCALE PLUS

Standard size 7 and 9

Standard size 12 and 15

10.2.3 Dimension Tables, Load Capacities and Torque Loads for Wide MINISCALE PLUS

Wide size 14 and 18

Wide size 24 and 42

10.2.4 MINISCALE PLUS Components and Operating Principle

MINISCALE PLUS is an optical incremental measuring system consisting of a MINIRAIL guideway system and the following additional components:

• A Measuring scale on the guideway
• B Optical sensor on the carriage
• C Flexible sensor printed circuit (must not be subjected to dynamic loads)
• D Interface module

Control cable E with D-Sub 9 connector must be provided by the customer; flexible cables should be used if necessary.

Interface modules are available in various design types. These are described in detail in the "Interface Modules" section.

Using a flat flex cable (FFC) between the flexible sensor printed circuit and the interface module allows flexible positioning of the interface module. FFC cables are suitable for dynamic loads. (For details, see Section 10.2.8)

Measuring Scale and Optical Sensor

The high-precision measuring scale is part of the hardened guideway surface with a scale increment of 100 µm. Two LEDs in the sensor illuminate the measuring scale. Due to illumination of different structural areas, bright and dark fields are formed. These optical signals are detected by the sensor and converted into electrical signals. The raw signals from the sensor are processed by the interface module.

The illumination level of the LEDs is actively controlled. This compensates for ageing effects in the system and for impurities on the measuring scale.

Interface Module Components

Interface Module

The raw signals are processed by the interface module and converted into standard output signals. Analogue or digital interface modules are available.

Ensure that the ZIF connector F is easily accessible and that the LED indicators on the interface module (G and H) are clearly visible. Unlike the analogue interface, the digital interface includes a compensation key I, which must also be easily accessible.

• C Flexible sensor printed circuit
• D Electronics (various design types available)
• F ZIF connector
• G Green LED (operating voltage indicator)
• H Red LED (error indicator)
• I Compensation key (digital interface module only)

Interface modules are available in the following design types:

For customers with electronics expertise, it is also possible, after consultation with SCHNEEBERGER, to assemble the digital interface module themselves and integrate it into their own electronics system.

Order code: KI

10.2.5 Signal Processing

For more information on signal processing, please visit our website download area: www.schneeberger.com

Analogue Output Format

Differential sin/cos analogue signals with reference pulse 1 Vpp (at 120 Ω).

The incremental signals sine and cosine are 90° apart and are related to the marks on the encoder scale. One electrical signal period (360°) corresponds exactly to a scale increment of 100 µm.

The reference pulse always electronically marks the same section of the sine and cosine signal paths. Therefore, the intersection of both signals within the reference pulse marks a precisely defined position on the measuring scale.

The sine signal either lags or leads the cosine signal, depending on the direction of travel.

Digital Output Format

Differential interpolated digital signals with reference pulse (A, B, R) TTL signals (RS422).

The digital interface module both processes the raw signals and interpolates the processed analogue signals. Interpolation achieves a resolution of 100 nm.

The digital signal waveform consists of A and B signals. The distance between two edges of signals A and B corresponds exactly to 100 nm. Therefore, the 100 µm increment of the encoder scale is divided into 1000 segments of 100 nm through interpolation. Signal A either lags or leads signal B, depending on the direction of travel.

The width of the reference pulse is the same as the distance between two signal edges of signals A and B (100 nm).

The edges of the incremental signals and reference signal are synchronised.

10.2.6 Incremental Track

In the standard version, the incremental track extends over the entire guideway length. Position and length can be adjusted according to customer requirements.

S1 = Incremental track start

S2 = Incremental track length

Limitations

• For analogue MINISCALE PLUS guideways, S2 must be at least 30 mm.

Reference Marks

Incremental measuring systems cannot determine the exact position at power-up. Therefore, a reference track is added next to the incremental track. One or more reference points can be marked on the reference track.

Standard Version

The standard reference position for all sizes is defined as follows:

• Reference positioning at the centre of the first and second fixing holes

Special Versions

Any number of reference marks can be selected at any position on the reference track. Reference marks must be synchronised with the measuring scale. This specifically means that reference marks can only be placed in multiples of 0.1 mm, as the scale pitch is 0.1 mm. A minimum distance of at least 1.5 mm should be maintained between reference marks. Additionally, the distance between the end of the incremental track and a reference mark must be at least 2 mm.

Limitations

• For sizes 7 and 9, the mounting holes on the guideway are located on the reference track. Therefore, for these two sizes, reference marks must be located between the mounting holes.
• When specifying reference marks, ensure that the carriage sensor can see them.

10.2.7 Analogue (1VSS) and Digital (TTL) Interface Module Pin Connections

MINISCALE PLUS offers 9-pin D-Sub male connectors or solder terminals as interface connection options.

9-pin D-Sub Male Connector or Solder Terminals:

10-pin ZIF Connector:

10.2.8 Extension Kit

When the interface module cannot be mounted directly on the sensor, an extension kit can be used. A flat flex cable (FFC) is used between the sensor printed circuit and the interface module.

Advantages of the Extension Kit:

• By moving the interface module to a non-moving position, the mass of the moving system can be reduced.
• The shielded FFC cables included in the extension kit are also designed for dynamic loading. The recommended minimum bend radius is 10 mm. In contrast, the flexible sensor printed circuit can only be installed statically.
• FFC cables provide low push force. This can be an advantage in cases where cables in cable chains are too rigid.
• FFC cables can also be folded once during installation.

FFC cables are available in three lengths: 250 mm, 400 mm and 600 mm. Extension cables are supplied with adapter boards.

Adapter

Used for electrical connection between the sensor printed circuit and the extension cable. Two ZIF connectors on the adapter are available for this purpose.

Clamp Plate

Can be used for strain relief or guiding the FFC cable. Two M3 spacer sleeves are mounted on the plate.

Base Plate

Can be used as a base or for clamping cables.

10.2.9 Lubrication

Overview

Lubrication is a design element and must therefore be defined during the development phase of the machine or application. If lubrication is only specified after design and construction are complete, operational difficulties are likely to occur. Therefore, a carefully designed lubrication concept is a sign of advanced and thoughtful design.

Parameters to Consider When Selecting Lubricants: