DS-58[20]-32 Absolute Posi on, Rotary Electric Encoder

Transcription

1 DS-58[20]-32 Data Sheet, V 1.0a, May DS-58[20]-32 Absolute Posi on, Rotary Electric Encoder The DS-58[20] is a member of the DS series of Electric Encoders, based on Netzer Precision proprietary technology. These encoders offer many advantages, some unparalleled: Low profile (10 mm). Hollow, floa ng sha. No bearings or other contac ng elements. High precision. High tolerance to temperature, shock, moisture, EMI, RFI and magne c fields. Analog or mul ple digital interface op ons. Extremely low power op ons. The DS-58[20] is suited to demanding applica on such as: aerospace, medical, instrumenta on, automa on, etc. Mechanical - common to all types Allowable moun ng eccentricity (2) ±0.3 mm Allowable rotor axial mo on (2) ±0.3 mm Rotor iner a 800 gr mm 2 Total weight Outer diameter / Inner diameter / Profile Material (stator, rotor) 36 gr 58 / 20/ 10 mm Ultem polymer Electrical - common to all types Supply voltage 5V ± 5% (3) Interconnec on 250 mm Teflon-coated, flying AWG-32 leads Environment - common to all types EMC (4) IEC , IEC Opera ng temperature range -55 C to +125 C (5) - analog output -55 C to +85 C (5) - digital output The holis c (1) structure of the Electric Encoder provides generous moun ng tolerance, thus obvia ng the need for internal ball bearings. The lack of bearings and components such as flexible couplers, glass disc, light sources and detectors, along with very low power consump on makes the DS-58[20] encoder virtually failure free. The internally shielded, DC operated Electric Encoder includes an electric field generator, a field receiver, a sinusoidal shaped dielectric rotor, and processing electronics. The outputs signals of Electric Encoder are analog Sine / Cosine represen ng the rota on angle. The digital outputs are obtained by further processing which may be either internal or external to the encoder. Rela ve humidity Shock endurance Vibra on endurance <98 % - non condensing IEC ; 100 g for 11 ms IEC ;20 g Hz Outputs op ons Analog Digital Sine/Cosine SSi AqB + Index Performance - common to all types Electrical Cycles/Revolu on Fine/Coarse channels (7) 32 / 3 Angular resolu on (using 12 bit A/D conversion) (8) 18 bits Sta c error (with offset compensa on) (9) < 20 mdeg Maximum opera onal speed (10) 1,500 rpm Measurement range Unlimited rota on

2 Digital SSi Interface (absolute posi on) DS Sn-02 Output signal parameters Signal latency (11) Output code Serial output SSi Clock SSi Monoflop me Clock Frequency Maximum payload Electrical parameters Current consump on ~250 μsec Binary Differen al RS-422 Differen al RS μsec MHz 19 bit ~ 180 ma The na ve outputs signals are analog Sine / Cosine represen ng the electric angle. The digital output - Synchronous Serial Interface (SSi) transmits the absolute posi on data from the Electric Encoder in response to controller clock pulses. The encoder and controller are linked by clock and data differen al signal lines. Figure 1 illustrates the SSi ming diagram as implemented in the Electric Encoder. The digital SSi op on also provides advanced calibra on and monitoring op ons using the NCP (Netzer Communica on Protocol) and factory supplied so ware tools. Electric Encoder SSi-CLK / NCP RX SSi-CLK / NCP RX SSi-DATA / NCP TX SSi-DATA / NCP TX Gnd 1 (gray) 2 (blue) 3 (yellow) 4 (green) 5 (black) Host System 120 5V 5V SSi - Wires color code # Name Color Func on 1 Clock + Grey 2 Clock - Blue SSi Clock 3 Data - Yellow 4 Data + Green SSi Data 5 GND Black Ground 6 +5V Red Power supply 5V 6 (red) Calibra on and analysis over NCP Absolute posi on Host system Electric Encoder - 2 -

3 Digital SSi Interface (absolute posi on) DS Sn-02 Figure - 1 n = total number of data bits. T = clock period (sec) - user defined. 1/T = clock frequency MHz (user defined). t1 = minimum me required for the encoder to freeze data and preset the shi registers before receiving the first rising edge to prompt the MSB t2 = data transmission delay (increases with cable length) t3 = required delay to refresh posi on data between subsequent posi on reads. Posi on calibra on & signal analysis with SSi interface: The Electric Encoder processing capabili es enable calibra on, built-in tests and advanced setup, using factory supplied so ware tools, such as: A. Simple calibra on procedure using the SSi Explorer (CAA, offsets and zero posi on se ng ). B. On-line aid for valida ng proper mechanical moun ng. C. On-line NCP protocol for calibra on and advanced analyisis

4 Digital AqB + Index interface (incremental) DS An-02 Output signal parameters Signal latency (11) Format Phase rela onship with CW sha rota on (as seen from top) Index pulse width Electrical parameters Current consump on 250 μsec Differen al RS-422 A leads B ½ A ~ 130 ma Wires color code # Name Color Func on 1 GND Black Ground 2 +5V Red Supply voltage 3 A+ Yellow 4 A- Yellow/Black 5 B+ Blue 6 B- Blue / Black 7 Z+ Orange 8 Z- White For factory use Quadrature outputs Index Host system Electric Encoder - 4 -

5 Analog Sine/Cosine output (absolute posi on) DS Output signal parameters Signal latency (11) 250 μsec Fine-mode output noise (DC to 1kHz) (12) 100 μv (p-p) Fine-mode output amplitude (13) 0.5V ± 20% Coarse-mode output amplitude 0.5V ± 20% Phase rela onship (CW sha rota on - seen Sine leads Cosine from top) Signal bandwidth DC to 1 khz Electrical parameters Output resistance <1 Ω Current consump on ~ 10 ma (14) Coarse and Fine channels The DS-58[20] has two opera on modes: a Coarse-mode and a Fine-mode - equivalent to two separate encoders in a common housing. The modes are selectable by a logic C/F command; logic 0 (0V to +0.5V) selects the Coarse-mode, which has 3 Electrical Cycle/Revolu on (EC/R) while logic 1 (+3V to +5V) selects the Finemode which has 32 EC/R. The switching me is less than 1 ms. The Coarse-mode outputs need to be read only upon system ini a on a er which the encoder is permanently switched to the Fine mode. Coarse and Fine sine/ cosine pairs are used to calculate the ini al absolute posi on, from that point tracking the Fine-channel outputs provides the absolute mechanical rota on angle with the specified accuracy and resolu on. All output signals are referenced to an internally generated voltage Vr (~2.25V) Absolute Posi on calcula on: The analog Sine /Cosine outputs convey the electric angle of the Coarse or Fine signals. The absolute mechanical angle is computed by digi zing the analog signals and applying factory-supplied algorithms. Please refer to AN-02 and AN-03. Wires color code # Name Color Func on 1 GND Black Ground 2 C/F Grey Coarse / Fine 3 Sine Blue Sine signal 4 Vr Green V reference 5 Cosine Yellow Cosine signal 6 +5V Red Power supply A/D Electric angle Algorithm Mechanical angle Electric Encoder Host system - 5 -

6 Notes 1. The output signals are generated by the whole area of the rotor - see AN Accuracy may degrade depending on moun ng tolerances and the Sine/Cosine amplitudes may exceed the A/D conversion range -see AN The encoder includes an internal 4.5V LDO voltage regulator. 4. Standard DS encoders are insensi ve to ESD, stray magne c and capaci ve coupling from the host system current consump on. However it is advisable to allow a discharge path of no more than several tens of kω between the machine sha and the electronic s ground, not leaving it electrically floa ng. 5. Consult factory. 6. For higher ingress protec on the encoder should be mounted inside a sealed enclosure. 7. The number of electrical sine/cosine cycles generated in one mechanical rota on. 8. The angular resolu on is determined by the ra o of the Fine - channel amplitude and the encoder inherent noise see AN Not including dynamic error. For higher sta c accuracy consult factory. 10. Determined by the Fine-channel EC/Rs and the internal low pass filters, for higher rota on speed consult factory. 11. An inherent signal delay inversely propor onal to the internal filter s cut-off frequency (1 khz, 3rd order Bessel) and resul ng in a dynamic error propor onal to the rota on speed - see AN For measuring the noise and valida ng the interconnec on see AN With the rotor at its nominal axial posi on - see AN For a micro-power version with current consump on down to 50 3V consult factory. Resolu on In bits Steps /360 mdeg /step Arc-sec /step mrad /step 12 4, , , , , , (DS-58) 262, , ,048, ,097, ,194, Related documents: DS-58[20] Mechanical Installa on Guide - 6 -

7 Ordering DS SG - 02 DS Product line OD EC/R Outputs 0 - Analog: Sine/Cosine A - Digital : AqB + index S - Digital : SSi Loose wires 250mm Resolu on CPR 4,096 8,192 Binary 16,384 32,768 65, ,072 Bit Code A B C D E F G 262,144 Decimal Encoder clamps Resolu on CPR 8,000 16,000 32,000 64, , ,000 Bit Code K L M N O P 250 mm Teflon - insulated, AWG-32 loose wires - 7 -

8 Demo Units: Demo units with a rota ng sha are available with analog or digital outputs, USB based interface with the encoder and SSi explorer enable instant setup for demonstra on, integra on and analysis. CAT # : DKIT-DS with analog output CAT # : DKIT-DS AG-02 with AqB + Index output CAT # : DKIT-DS SG-02 with SSi output - 8 -