HEIDENHAIN IK 220 - Handbuch (Seite 73)

Hardware
73
Encoder inputs
The IK 220 supports encoders with the following interfaces:
• 11 µA
PP
• 1 V
PP
• EnDat 2.1
• SSI
The power supply for the encoders (typ. 5.12 V) is generated
from the +12 V of the PCI bus. Max. 800 mA of the +5 V power
supply for the encoders may be used for both axes.
The additional current taken from the +12 V of the PCI bus is:
I
(12V)
= I
(5V)
* 5.12 V * 1.35 / 12 V
Example: I
(5 V)
= 0.8 A * 5.12 V * 1.35 / 12 V = 461 mA
It must be ensured that the power supply limits for the encoder
are not exceeded. A voltage converter (370 225-xx) can be used
for large cable lengths. The voltage converter has an efficiency
of approx. 72 %, meaning that the permissible current con-
sumption of both axes is reduced to 0.72 * 800 mA = 576 mA.
Specification of the 11-µA
PP
interface
Signal amplitudes
I
1
, I
2
(0°, 90°)
I
0
(reference mark )
7 µA
PP
to 16 µA
PP
3.5 µA to 8 µA
Signal levels for error
message
≤
2.5 µA
PP
Maximum input frequency Standard: 33 kHz,
switchable to 175 kHz
Cable length Max. 60 m