SSI encoder interface (encoder 3)

SSI clock frequency

200 kHz (fixed value)

Frequency of the clock signal within a pulse train controlled by the CSA31A safety option.

SSl pause time

20 – 200 µs

The pause time t_P controlled by the inverter is the minimum waiting time between the end of one pulse train and the start of the next pulse train. The pause time resolution is 1 µs.

The pause time must be greater than the monoflop time specified by the encoder manufacturer.

SSI frame rate

1 ms

Rate at which the position is polled from the encoder.

Startup time

0 – 32 s

Required time until an SSI encoder can supply data after the supply voltage is switched on.

Refresh time

0 – 30 ms

Encoders need time to update the SSI position. The time between 2 updated positions is the refresh time. The resolution is 1 µs.

Static tolerance band

10⁸ (≈10% of the entire range of values)

Static tolerance band for monitoring the absolute position. Setting value in encoder increments.

Speed filter time

1 – 300 ms

Time interval in which position changes of the encoder are added up to obtain the speed by division. Also sets the response time of the speed-related safety sub-functions.

Acceleration filter time

10 – 100 ms

Time interval in which position changes of the encoder are added up to obtain the acceleration by dividing twice. Also sets the response time of the acceleration-related safety sub-functions.

SSI fault tolerance

1 – 10

Number of faulty SSI frames that are still accepted by the system without triggering a fault.

SSI frame length

≥ 48 bits

Number of all data bits and status bits.

Position data

≥ 32 bits

Number of data bits.

Coding of position data

as binary code and Gray code

Maximum length of the encoder cable

30 m