A25S Absolute Rotary Encoder - GURLEY Precision Instruments

Catalogue A25S Absolute Rotary Encoder

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External Electronics Assembly

SETTING THE DIP SWITCHES

Open the electronics assembly by removing the 4 Philips-head screws and lifting off the top cover (the one with the label). The dip switches can be set as follows (this information is also printed on the pc board):

Position 1 Position 2

Count increases Parity is even

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ELECTRICAL INSTALLATION

We recommend that the +5V supply (300 mA max, excluding atypical data bus termination requirements) for the encoder be provided from a linear regulated power supply located within 20 feet of the installation. Dual supply and return pins are provided to facilitate remote sensing, an option provided on most commercially available linear supplies. A cleanly regulated switch-mode power supply may be adequate in some cases. If the encoder is operated from the same supply as the customer's digital interfacing logic, an LC filter to suppress RFI on the instrument branch of the supply may be desirable. Where possible, terminate the instrument shield (Pin 13 and the D-Sub connector shell) at circuit ground potential as close as possible to the ground terminal of the power supply. The cover is effective primarily against electric field interference. In cases where intense magnetic field disturbances are expected, attention to cable routing and additional magnetic industrial shielding may be wise precautions.

These recommendations should be sufficient to assure reliable operation. However, optical encoder installations are known for their mechanical and electrical variety. Gurley will gladly render applications assistance for difficult installations.


	rotation
	Count increases OFF with cw shaft	Parity is odd

SETTING THE DIP SWITCHES

It may be desirable to unplug the electronics to snake the cable through a tight spot. First, open the electronics assembly by removing the 4 Philips-head screws and lifting off the top cover (the one with the label). Carefully unplug the ribbon cable and the separate shield connector from the electronics board. When re-mating the transducer to the electronics, make sure that they have the same serial number. A mismatch of these components will result in gross position errors and void the warranty.

MOUNTING THE ELECTRONICS

The simplest way to mount the electronics is with bracket AX06626 for a single box, or bracket AX06627 to mount a pair of boxes, as in an azimuth/elevation or other two-axis systems. Another choice is to bolt the box directly to a mounting surface: First, open the electronics assembly by removing the 4 Philips-head screws and lifting off the top cover (the one with the label). Unscrew 4 hex stand-offs, and lift out the electronics board and the cable; you don't have to unplug the cable from the pc board. Drill two clearance holes in diagonally opposite corners of the bottom of the lower cover. There's plenty of room under the pc board for screw heads. After the lower cover is bolted in place, carefully reassemble the package by reversing the previous three steps. Or, if your enclosure provides adequate mechanical and EMI protection, you can use the board without the box (order PKG code 0). You can mount the board on stand-offs, but be sure to provide adequate strain relief for the ribbon cable from the transducer.

OUTPUT PINOUTS

SHIELDED MALE 25-PIN D SUBMINIATURE CONNECTOR


PIN	14-BIT	15-BIT	16-BIT	17-BIT	SERIAL
1	D5	D6	D7	D8	NC
CM	D4	D5	D6	D7	NC
CO	D3	D4	D5	D6	NC
4	D2	D3	D4	D5	NC
	D1	D2	D3	D4	NC
6	D0	D1	D2	D3	NC
7	NC	D0	D1	D2	NC
	NC	NC	D0	D1	NC
9	OEL	OEL	OEL	D0	INT
10	INT	INT	INT	INT	INT
11	+5V	+5V	+5V	+5V	+5V
12	+5V	+5V	+5V	+5V	+5V
13	CASE	CASE	CASE	CASE	CASE
14	D13	D14	D15	D16	NC
15	D12	D13	D14	D15	NC
16	D11	D12	D13	D14	NC
17	D10	D11	D12	D13	NC
18	D9	D10	D11	D12	NC
19	D8	D9	D10	D11	NC
20	D7	D8	D9	D10	DATA
21	D6	D7	D8	D9	DATA
22	OEH	OEH	OEH	OE	CLK
23	PAR	PAR	PAR	PAR	CLK
24	GND	GND	GND	GND	GND

25	GND	GND	GND	GND	GND

PERFORMANCE CERTIFICATION

Before shipment, Gurley tests all absolute encoders for monotonicity, which guarantees that all output code states are present and in the correct order, and for accuracy, which verifies that the digital output matches the shaft angle input within the stated tolerance. These tests are performed on our exclusive METRA test system (Master Encoder for Testing Rotary Accuracy), and a printed accuracy plot accompanies each encoder.

The heart of METRA is an exclusive Gurley-designed optical encoder with a resolution of 2²¹ measuring steps/rev, and NIST-traceable absolute accuracy of ±1/3 arcsec. (The certified accuracy is limited by available angle standards, not by METRA itself.)

When testing for accuracy, the encoder under test (EUT) is coupled to METRA with precision fixturing. As the two industrial encoders are rotated together, the position information from METRA is used to interrogate the EUT at 2,097,152 positions around a revolution. Thus, this test verifies the location of every single output state of the EUT. This method reveals all encoder errors and does not depend on statistical assumptions based on an incomplete data set.

Gurley Precision Instruments 514 Fulton Street Troy, NY 12180 U.S.A. (800) 759-1844, (518) 272-6300, fax (518) 274-0336, Online at www.gurley.com, e-mail: info@gurley.com

A25S

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