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Mini Multimode Encoder Signal Filters
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Request further information or a quote Read Eliminating Phantom Movement in Encoder Applications paper Technology Overview (pdf) Product Leaflet (pdf) Encoder filter FAQ (Frequently Asked Questions) Jump to Model Selection Table Buy Mini Encoder Filters Online
The filters complement, safeguard, maintain and extend the capabilities and performance of incremental encoders (or pulse generators). Their design is characterized by typical industrial application considerations: low ownership cost, standard interfacing, fool-proof installation, transparent operation, results-oriented and all-inclusive design.
Mini Multimode Encoder Filter
Mini multimode encoder signal filter
The filters remove all types of electrical noise (common and differential mode, dV/dt transients, ground loop generated etc.) in the encoder signal lines as well as the corrupting effects of mechanical noise and vibration (phantom movement, dither etc.). They reconstruct the encoder signals to reflect the correct encoder position and speed signaling. Performance is safeguarded and problems such as:
  • Motion system position drift,
  • Home reference loss,
  • False triggering of the receiving inputs, and
  • Receiving input saturation, latch-up or failure
are eliminated. (The subject is treated extensively and in detail in our paper Eliminating Phantom Movement in Encoder Applications).  See also the Frequently Asked Questions page.

In addition to the above, our specialty multimode frequency averaging filters process the encoder signals to reproduce them at average input frequency in speed/velocity control applications.

The Mini line of multimode filters are standard, all-in-one, comprehensive products, each device addressing all and any combination of known encoder application issues.  The filters process digital quadrature encoder signals with the following features:

  1. Unfiltered: the outputs are buffered replicas of the inputs.
  2. Filtered: the encoder inputs are processed for electronic noise only.
  3. Recovered x1: the encoder inputs are processed for electronic noise and analyzed for mechanical position to recover corrupted motion sequences. The outputs are in quadrature format and the mark (or index) channel is processed for electrical noise.
  4. Recovered x4: Same as the Recovered x1 mode, but with output resolution quadrupling. The output signals are a clock/direction or an up/down pair at four times the input frequency instead of the quadrature format.

The above all-in-one, multimode approach is justified when considering that in practical applications there is typically more than one mechanism at play eroding encoder performance at any time (see our paper on this or the encoder filter FAQ page). This makes a multimode filter the only effective, efficient, viable and conclusive solution to encoder noise problems.

Model options are characterized by input/output type and speed capability:

Mini Multimode Encoder Filter Model Line-up and Features Overview
Model Single-ended input types Differential input types, Single-ended output types Differential output types Available speed grades Power supply Buy Online
EFD44   EIA422   EIA422 Basic 5 VDC (input) and 5 VDC (output) Yes
EFD42S   EIA422 10-28 V PNP and Push-Pull only   Basic 5 VDC (input) and 10-28 VDC (output) Yes
EFD42D   EIA422 All 10-28 V 10-28 V Basic 5 VDC (input) and 10-28 VDC (output) Yes
EFD24 All 10-28 V 10-28 V   EIA422 Basic 10-28 VDC (input) and 5 VDC (output) Yes
EFD22S All 10-28 V 10-28 V 10-28 V PNP and Push-Pull only   Basic 10-28 VDC (input) and 10-28 VDC (output) Yes
EFD22D All 10-28 V 10-28 V All 10-28 V 10-28 V Basic 10-28 VDC (input) and 10-28 VDC (output) Yes

The speed grade specifies the maximum quadrature input frequency which can be processed.  The limit is different for each filter mode:

Maximum Quadrature Input Frequency Capability per Filtering Mode
Speed Grade Unfiltered Filtered Recovered x1 Recovered x4
Basic 300 kHz 125 kHz 100 kHz 31.3 kHz

The Terminator series addresses more demanding applications featuring higher speed processing, an internal twin isolated supply and a cast aluminium IP65 enclosure.

You can buy small quantities of all our filters online here.

OEM Encoder Filter
The technology is also available
in custom versions for OEMs.

Download technology overview PDF leaflet, product PDF leaflet or request further information or a quote/offer

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