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IMD 100 Integration manual 4189360015 Rev. G
Electrical HW connections and requirements
Page 43 of 243
Info
Some SSI encoders have no connector and the cable is already connected to the encoder
from the factory.
5.3.4.1 SSI encoder requirements
Only absolute encoder with some specific data formats is supported. The SSI encoder must comply
with the following requirements:
Unit
Specifications
Note
SSI Encoder type
N/A
Absolute encoder, single-turn,
or multi-turn
Incremental encoder is not
supported
SSI encoder supply
voltage
V DC 5 or 24
SSI encoder current
A DC 24 V DC: Max. 0.2
5 V DC: Max 0.5
Internal thermal fuse in IMD
SSI encoder interface
differential input / output
V DC Complies with RS485
(IMD input impedance is 150 Ω)
SSI encoder resolution
Bits
Single-turn: 12+1
Multi-turn: 12+12(+1)
Single turn: 12 bit resolution per
revo special bit
Multi-turn:
12 bit resolution per one revo
12 bits for number of turns + special
bit (special bit is optional)
SSI encoder output format
N/A
Single-turn: Binary
Multi-turn: Gray code
SSI encoder clock
frequency
kHz
The top of the clock frequency
range must be higher than
500 Hz
(the IMD clock frequency is
approximately 400 kHz)
The clock pulses sent from the IMD are according to the following:
Info
After sending the LSB (multi-turn) or special bit (single-turn), the encoder sends a zero.
This zero is used to determine whether the SSI input is OK (status in Reg. 0x9B, bit 31). If
a wrong type encoder is configured, the SSI input indication will be mainly off, but at some
positions it might be on.
tp (rest position)
923
S
31 clock pulses
2.5
S
(400 kHz)