Netzer Precision VLP-247 Hollow Shaft Rotary Encoder Kit Encoder User Guide

September 27, 2024
Netzer Precision

Specifications

  • Angular resolution: 18-20 bit
  • Nominal position accuracy: Not specified
  • Maximum operational speed: 4,000 rpm
  • Measurement range: Single turn, unlimited
  • Rotation direction: Adjustable CW/CCW*
  • Built In Test BIT: Optional
    • Default same direction from bottom side of the encoder

Product Information

The VLP-247 Absolute Hollow Shaft Rotary Encoder Kit Encoder is a precision encoder designed for harsh environment applications. Based on capacitive technology developed by Netzer Precision Position Sensors, this encoder is built to meet the requirements of demanding applications.

Product Usage Instructions

Mechanical Mounting
Refer to the Mechanical Mounting section in the user manual for detailed instructions on mounting the encoder. Follow the End-of-Shaft Installation guidelines for proper installation.

Operational Mode
The encoder operates in SSi / BiSS mode. Please refer to the user manual for specific instructions on configuring and operating the encoder in these modes.

FAQ

  1. Q: What is the maximum operational speed of the VLP-247 encoder?
    A: The maximum operational speed of the VLP-247 encoder is 4,000 rpm.

  2. Q: How long has the capacitive technology used in the VLP series been developed?
    A: The capacitive technology used in the VLP series has been developed and improved for over 20 years by Netzer Precision Position Sensors.

VLP Encoders Introduction

Designed to meet the requirements of the most demanding applications
The VLP series of Electric Encoders™ are a line of encoders designed for harsh environment applications. These encoders are based on capacitive technology which have been developed and improved for over 20 years by Netzer Precision Position Sensors.

The VLP encoders are characterized by the following features that sets them apart from other similar encoders:

  • Low profile
  • Hollow shaft (Stator / Rotor)
  • No bearings or other contact elements
  • High resolution and excellent precision
  • Immunity to magnetic fields
  • High tolerance to temperature extremes, shock, moisture, EMI, RFI
  • Very low weight
  • Holistic signal generation and sensing
  • Digital interfaces for absolute position

The holistic structure of the VLP Electric Encoder™ makes it unique. Its output reading is the averaged outcome of the entire circumference area of the rotor. This inherent design characteristic provides the VLP encoder with outstanding precision as well as a tolerant mechanical mounting. The absence of components such as ball bearings, flexible couplers, glass discs, light sources & detectors, along with very low power consumption, enables the VLP encoders to deliver virtually failure-free performance.

Technical Specifications

General

Angular resolution 18-20 bit
Nominal position accuracy ±0.006°
Maximum operational speed 4,000 rpm
Measurement range Single turn, unlimited
Rotation direction Adjustable CW/CCW*
Built In Test BIT Optional
  • Default same direction from bottom side of the encoder

Mechanical

Allowable mounting eccentricity ±0.1 mm
Allowable axial mounting tolerance ±0.3 mm
Rotor inertia 876,053 gr · mm2
Total weight 220 gr
Outer Ø / Inner Ø / Height 247 / 171 / 9 mm
Material (stator / rotor) FR4
Nominal air gap (stator, rotor) 1 mm

Electrical

Supply voltage 5V ± 5%
Current consumption ~90 mA
Interconnection Cable (standard 250mm)
Communication SSi, BiSS-C
Serial output Differential RS-422
Clock frequency 0.1-5.0 MHz
Position update rate 35 kHz (Optional – up to 375 kHz)

Environmental

EMC IEC 6100-6-2, IEC 6100-6-4
Operating temperature -40°C to +105°C
Storage temperature -55°C to +125°C
Relative humidity 98% Non condensing
Shock endurance / functional 100g 6msec saw-tooth per IEC 60068-2-27:2009 40g

11msec saw-tooth per MIL-810G
Vibration functional| 7.7grms @ 20 to 2000 Hz per MIL-810G Category 24
Protection| IP 40

Ordering Code

Mechanical Drawings

Unless otherwise specified

  • Dimensions are in: mm Surface finish: N6

Linear tolerances

  • 0.5-4.9: ±0.05 mm 5-30: ±0.1 mm
  • 31-120: ±0.15 mm 121-400: ±0.2 mm

Mechanical Interface Control Drawing

Cable options

Netzer Cat No. CB 00014 CB 00034
Cable type 30 AWG twisted pair x 3 28 AWG twisted pair x 3
Wire type 2 x 30 AWG 25/44 tinned copper Insulation: PFE Ø 0.15
OD: Ø 0.6 ± 0.05 mm 2 x 30 AWG 40/44 tinned copper Insulation: PFE Ø 0.12

OD: Ø 0.64 ± 0.05 mm
Temp. Rating| -55°C to +150°C
Braided shield| Thinned copper braided 95% min. coverage
Jacket| 0.45 silicon rubber (NFA 11-A1)| 0.44 silicon rubber (NFA 11-A1)
Diameter| Ø 2.45 ± 0.16 mm| Ø 3.53 ± 0.16 mm

Storage and Handling

  • Storage temperature: -55°C to +125°C
  • Humidity: Up to 98% non-condensing

ESD Protection
As usual for electronic circuits, during product handling do not touch electronic circuits, wires, connectors or sensors without suitable ESD protection. The integrator / operator shall use ESD equipment to avoid the risk of circuit damage.

ATTENTION OBSERVE PRECAUTIONS FOR HANDLING ELECTROSTATIC SENSITIVE DEVICES

Product Overview

Overview
The VLP-247 absolute position Electric Encoder™ is a rotary position sensor developed for demanding applications. Currently it performs in a broad range of applications, including defense, homeland security, medical robotics and industrial automation. The Electric Encoder™ non-contact technology provides accurate position measurement through the modulation of an electric field. The VLP-247 Electric Encoder™ is a kit-encoder, i.e., its rotor and stator are separate.

  1. Encoder stator
  2. Encoder rotor

Unpacking – standard order
The package of the standard VLP-247 contains the encoder Stator & Rotor.

Optional accessories:

  1. CNV-0003, RS-422 to USB converter (with USB internal 5V power supply path).
  2. NanoMIC-KIT-01, RS-422 to USB converter. Setup & Operational modes via SSi /BiSS interface.
  3. RJ VLP-247 rotary jig
  4. DKIT-VLP-247-SG-S0, Mounted SSi encoder on rotary jig, RS-422 to USB converter and cables.
  5. DKIT-VLP-247-IG-S0, Mounted BiSS encoder on rotary jig, RS-422 to USB converter and cables.

Installation flow chart

Electric Encoder Software Installation

The Electric Encoder Explorer (EEE) software:

  • Verifies correct mounting for an adequate signal amplitude
  • Calibration of offsets
  • General set up and signal analysis

This section describes the steps associated with installing the EEE software application.

Minimum requirements

  • Operating system: MS windows 7/ 10, (32 / 64 bit)
  • Memory: 4MB minimum
  • Communication ports: USB 2
  • Windows .NET Framework, V4 minimum

Installing the software

  • Run the Electric Encoder™ Explorer file found on Netzer website: Encoder Explorer Software Tools
  • After the installation you will see Electric Encoder Explorer software icon on the computer desktop.
  • Click on the Electric Encoder Explorer software icon to start.

Mechanical Mounting

Encoder mounting – End-of-Shaft Installation

Typical encoder installation uses

  • Mounting screws Socket Head Cup Screw 12xM2, 6 each per stator & rotor.
  • Mounting dowel pins 4xØ2, 2 each per stator & rotor (not included with the encoder).

Encoder stator / Rotor relative position
For proper performance the air gap should be 1 mm ±0.3 mm

In an optimal mounting, the signal amplitude values generated by the encoder, would be in the middle of the range of the signal plot shown in the Encoder Explorer software (see plot below). This may vary according to the encoder type. Verify proper rotor mounting with the Encoder Explorer tools “Signal analyzer” or “Signal verification process.”

Note: for more information please read section 7

Electrical Connection

This chapter reviews the steps required to electrically connect the encoder with digital interface (SSi or BiSS-C).

Connecting the encoder

The encoder has two operational modes:
Absolute position over SSi or BiSS-C
This is the power-up default mode

SSi / BiSS interface wires color code

Clock + Grey Clock
Clock – Blue
Data – Yellow Data
Data + Green
GND Black Ground
+5V Red Power supply

SSi / BiSS output signal parameters

Output code Binary
Serial output Differential RS-422
Clock Differential RS-422
Clock frequency 0.1- 5.0 MHz
Position update rate 35 kHz (Optional – up to 375 kHz)

Digital SSi Interface
Synchronous Serial Interface (SSi) is a point to point serial interface standard between a master (e.g. controller) and a slave (e.g. sensor) for digital data transmission.

Built In Test option (BIT)
The BIT indicates critical abnormality in the encoder internal signals.
‘0’ – the internal signals are within the normal limits, ‘1’ – Error
The Part Number of the encoder indicates whether the encoder includes BIT. If no BIT is indicated in the PN, there is no additional error bit.

  Description Recommendations
n Position resolution 12-20
T Clock period
f= 1/T Clock frequency 0.1-5.0 MHz
Tu Bit update time 90 nsec
Tp Pause time 26 – ∞ μsec
Tm Monoflop time 25 μsec
Tr Time between 2 adjacent requests Tr > n*T+26 μsec
fr=1/Tr Data request frequency

Digital BiSS-C Interface
BiSS – C Interface is unidirectional serial synchronous protocol for digital data transmission where the Encoder acts as “slave” transmits data according to “Master” clock. The BiSS protocol is designed in B mode and C mode (continuous mode). The BiSS-C interface as the SSi is based on RS-422 standards.
Built In Test option (BIT)
The BIT indicates critical abnormality in the encoder internal signals.
‘1’ – the internal signals are within the normal limits, ‘0’ – Error
The Part Number of the encoder indicates whether the encoder includes BIT. If no BIT is indicated in the PN, the error bit is always 1.

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