Using SSI encoder
SSI support details
As SSI is loosely defined standard, drive's SSI support may not cover all possible variations of the protocol. The following characteristics are supported:
- Read clock 1.5-2 MHz
- Strectched first clock for slower encoders
- Multiturn & singleturn readout
- Multiturn resolution from 0-16 bits
- Singleturn resolution 4-32 bits
- Sum of MT+ST resolutions must be between 4 and 32 bits
- Binary and Gray code support
Current firmware version limitations:
- No absolute encoder information is utilized, motor still needs to do Phasing a.k.a. phase search and Homing to get absolute operation.
List of tested SSI encoders:
|AMS||AS5311||12 bit magnetic encoders||All OK|
|RLS||Orbis BR10SCB14B12BD00||14 bits absolute||All OK|
|SICK||TTK70-AXA0-K02||24 bits absolute, gray code||All OK|
|Kübler||8.F3663.4121.G322||12 bit multiturn, 13 bit single turn, gray code||All OK|
|Zettlex||INC-4-100-211001-SSI2-RFC6-5-AN||21 bit singleturn, Zettlex's "SSI2" format||Ok with workaround (use [FBMT] parameter as described below).
Zettlex encoders have uncommon SSI data formats with leading zeroes or status bits while GraniteCore drives assumes SSI data to begin with position information. Use Multi-turn bitsFBMT to skip those non-position info bits if necessary, and in such case keep Apply absolute position readingHAP disabled. However, if possible, choose Zettlex's SSI3, SSI5 or SSI8 formats which output position data bits first.
|Zettlex||INC-3-75-211001-SSI1-RFC9-12-AN and INC-4-37.080-171001-SSI1-RC371-12-S||Zettlex's "SSI1" format|
If you have tested another kind of encoder, please help us to inform the community by letting us know your encoder model and result by dropping a message into Granite Devices support.
Wiring SSI encoder
Wiring of SSI depends on the variant of SSI protocol present.
Typical SSI encoder has differential signal lines and a supply voltage lines:
- Power supply lines (2 wires)
- Clock input (2 wires)
- Data output (2 wires)
Connection to IONI Pro drive by following table:
|BiSS wire||IONI drive pin||IONICUBE D-Sub 15 pin number||Remarks|
|Cable shield||Connector shell|
|5V input||9||Pin 9 is 5V supply output from IONICUBE to encoder|
|Cable termination resistors may be necessary for reliable operation, for more details, see Terminating differential encoder lines.|
AMS SSI encoder chips
AMS SSI encoders are wired following way to IONI encoder connector:
|AMS wire||IONI drive pin||IONICUBE D-Sub 15 pin number||Remarks|
|VDD5V (5V input)||9||Pin 9 is 5V supply output from IONICUBE to encoder|
Refer to IONI & IONICUBE user guide for more info on wiring encoders.
To configure SSI, use Granity version 1.11.1 or later. Configuration steps:
- Find out encoder MT and ST resolutions from encoder manufacturer's data sheet
- Select Serial data encoder from Feedback deviceFBD
- Select SSI type from Serial encoder typeFBS
- Set number of MT and ST bits into parameters Single-turn bitsFBST and Multi-turn bitsFBMT. If MT not specified in encoder data sheet, set it zero.