HEIDENHAIN IK 220 - Handbuch (Seite 71)

Technical Description of the IK 220
71
The IK 220's interpolation electronics subdivides the signal
period of the input signal up to 4096-fold.
The 44-bit wide measured value is formed from the
interpolation value (12 bits) and the value of the period counter
(32 bits). The measured values are saved in 48-bit wide data
registers, whereby the upper bits are expanded in two's
complement representation with sign.
The measured values are called and latched either through
external latch inputs, via software or timers, or by reference-
mark traverse.
The counter components contain a CPU; the appropriate
firmware is loaded to the counter.
Cycle time of the firmware: 25 µs
Offset, phase and amplitude of the sinusoidal encoder signals
can be adjusted by software.
Time to access measured values
Incremental encoders
• Without compensation of the encoder signals, without
calculation of compensation values:
Max. 100 µs
• With compensation of the encoder signals, without
calculation of compensation values:
Max. 110 µs
• With compensation of the encoder signals, with calculation of
compensation values:
Max. 160 µs
EnDat/SSI
The access time varies depending on the encoder.
EnDat: 440 kHz clock frequency (one-time call)
SSI: 360 KHz clock frequency