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MS 20
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Open Linear Encoder with single-field scanning
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Easy mounting as a result of large mounting tolerances
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High insensitivity to contamination by use of an extensive Quasi-singlefield scanning principle
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High traversing speed
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Integrated subdividing electronics in the encoder head for up to times 100 interpolation (before quadrature)
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"True" Reference Mark (accurate and repeatable from both traversing directions)
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MS 20: Two independent switch signals (optical) for individual functions
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MS 21: Position of Reference Mark can be selected by the customer
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MS 21: One switch signal for special functions
Scanning Principle
The MS 20, MS 21 incremental Linear Encoders works with the imaging, photoelectric measuring principle and a quasi-singlefiled reflective scanning method. As scale graduation pattern a steel tape (with gold grating) or a glass scale (with chrome grating) with 40µm grating pitch is used. The light from an infrared LED with a small light emitting surface is collimated paralled by a condenser lends and directed through the scanning reticle to the scale. When the scale is moved relative to the encoder head, the light is modulated by the scale gratings and produces a periodic intensity signal that is converted into electrical signals by photo elements back in the encoder head.
The scanning reticle is designed to allo for a large mounting gap and liberal mounting tolerances. This system is insensitve to waviness of the steel tape due to poor mounting conditions. Any minor differences in the grating period of the scale or the scanning reticle will not cause a measuring problem due to the large continuous pattern reflected onto the structured sensor.
This sensor consists of multiple photo elements connected in a pattern to generate four sinusoidal signals, each shifted by 90º. All four signals are generated from one scanning field and all four signals are equally influenced by any contamiantion simultaneously. When all four signals are influenced at the smae time by the same amount, interpolation error is eliminated. |
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*Specification subject to change witout notice*
 MS20 Brochure
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System
resolution
µm |
Accuracy-
grades
Glass scale
±µm/m |
Accuracy-
grades
Steel tape scale
±µm/m |
Grating
pitch
µm |
Output signal
analog
(Vpp) |
Output signal
digital
(interpolation) |
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see * |
±3, ±5 |
±5, ±15 |
40 |
MS 20.04, MS 21.04 |
-- |
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2 |
±3, ±5 |
±5, ±15 |
40 |
-- |
MS 20.64, MS 21.64 (5) |
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1 |
±3, ±5 |
±5, ±15 |
40 |
-- |
MS 20.74, MS 21.74 (10) |
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0,5 |
±3, ±5 |
±5, ±15 |
40 |
-- |
MS 20.44, MS 21.44 (20) |
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0,4 |
±3, ±5 |
±5, ±15 |
40 |
-- |
MS 20.54, MS 21.54 (25) |
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0,2 |
±3, ±5 |
±5, ±15 |
40 |
-- |
MS 20.84, MS 21.84 (50) |
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0,1 |
±3, ±5 |
±5, ±15 |
40 |
-- |
MS 20.94, MS 21.94(100) |
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| * = depending on external interpolation |
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Max. measuring length: |
glass scale to 3040 mm
steel tape scale to 8840 mm |
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Position of the Reference Mark:
(RI) |
standard separated by distances of n x 50 mm
resp. at any location selected by customer
MS 21: selected by customer |
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Output analog: |
typical 1 Vpp |
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Output digital: |
square wave signals (single ended)
with integrated Subdividing Electronics
Maximum Cable length. 10 m
square wave signals (differential) via Line Driver RS 422 standard
with integrated Subdividing Electronics
with analog signal switch-over for setup |
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Tape carrier:
Different types
are available
(Downloads at the end
of the page) |
MS 20/21.xx GK = Glass scale with adhesive tape
MS 20/21.xx GA = Glass scale mounted onto aluminium carrier,
and mounting bolts holes
MS 20/21.xx MK = steel tape scale with adhesive tape
MS 20.xx MP = steel tape scale in aluminium carrier with clamping element,
carrier glued
MS 21.xx MP = on request
MS 20.xx MT = steel tape scale in aluminium carrier with clamping element,
and mounting bolts holes
MS 21.xx MT = on request
MS 20/21.xx MA = steel tape scale mounted onto aluminium carrier,
and mounting bolts holes
MS 20/21.xx MS = steel tape scale mounted onto steel carrier,
and mounting bolts holes
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*Specification subject to change without notice*
Dimensions and Mounting possibilities:
(Adobe Acrobat 5.0 or higher required) |
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