SSI Rotary Absolute Encoders

Knowledge Base: Third Party Recommendations Sensors
1

Many Delta customers have successfully used the following absolute rotary encoders with SSI output:

Dynapar
Delta has tested the multi-turn SSI AI25.
According to the specs, the SSI versions of the following encoders are also compatible: AC36, AD25, AD34, AD35, AD36 (not more than 31 or 32 bits total), AR62/63, AX65, AX70/71
http://www.dynapar.com Search for AI25

Encoder Products Company
A36S: Single and multi-turn, 8 to 14 bits per turn, 40 bits for turns, for a max of 54 bits (no kidding!) However, the RMC75 and RMC200 can only handle up to 32 bits, and the RMC150 SSI can handle only 31 bits.
These are fairly small form factor encoders, with very reasonable prices!
Important! Order the P2 option for SSI.
http://encoder.com/products/absolute-encoders/absolute-encoders/model-a36sb/

Leine Linde
Delta has tested the multi-turn ISA 608 SSI gray
According to the specs, the SSI versions of the following encoders are also compatible: 500 Robust, 600 Industrial, 900 Premium
http://www.leinelinde.com/products/heavy-duty-encoders/

Scancon
Has some very small form factor SSI encoders. Make sure to choose an SSI encoder with the RS-422 interface.
For example: 2RMHF-SSI: Single- or multi-turn
scancon.dk/

Sensata (formerly BEI Sensors
H25, H25X, HS35, L18: Single-turn.
Important! Order the S3 option for SSI.
http://www.sensata.com

HMT25: Multi-turn. Make sure to order the number of turns as 4096. Lower numbers of turns will cause unused bits, which will confuse the Count Offset adjustment portion of RMCTools’ Scale/Offset wizard.
http://www.beiied.com/PDFs2/HMT25_Absolute_Encoder.pdf

Sick Stegmann
AFS60: Single-turn
AFM60: Multi-turn

If you will be using the encoder on a rotary axis, specify the resolution as a power of 2 *(e.g. 4096, 8192, 32,768).

For more details, or to suggest a product to be added to this list, send an email to support@deltamotion.com.

2

What is the “S3 Option”. Says to consult the factory.

3

It appears the S3 simply means SSI. The reference to note 3 seems to apply to all the Voltage/Output options. Then note 3 itself doesn’t mention anything about SSI.
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4

Hi,
We are interfacing the absolute encoder AD36/1219af.OR/BV with the drive. The data sheet suggests that the output is gray code and 19/12 bit is the resolution, but we are struggling in identifying the bits, such as how many bits are for multi turn or single turns, these information is not given,
Kindly ifr you may help out.

Muzammil

5

Hello Muzammil,

Looking at the datasheet, the 12/19 you are referring to is 12 bits for Multiturn data, and 19 bits for single turn data, for a total of 31 bits.

This means this sensor can track up to 2^12 = 4096 full rotations before the count wraps over, and then 2^19 = 524,288 counts within a single rotation of the encoder. So, it depends on what units your application needs. For example, if you need scaling in degrees, you would have 524288/360 = 1456.356 counts/degree. The encoder will simply give you a number, total counts. How you scale that number depends on what you need to do with your system and how accurate you need the measurement to be.

Hopefully this helps.