HEIDENHAIN PWM 8 User Manual
Page 54
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TTL signal level
UH
≥
2.5 V with
−
IH = 20 mA
UL
≤
0.5 V with IL = 20 mA
Load capacity
−
IH
≤
20 mA
IL
≤
20 mA
CLoad
≤
1000 pF
Switching times
Rise time:
t+
≤
100 ns
Fall
time:
t
−
≤
100 ns
The fault detection signal
UaS
indicates a malfunction, such as break of a supply line, lamp failure etc.
TTL square-wave signals can be transferred over cable lengths up to 300 m to the subsequent electronics.
For this purpose a supply voltage of 5 V
±
10% (for RAN 460: range between 10 and 30 V) must be ensured
at the linear or rotary encoder.
In the subsequent electronics TTL square-wave signals can be interpolated 100-fold max. by means of
phase-locked control loops.
Recommended input circuit of the subsequent electronics
Recommended differential line receivers
AM 26 LS 32
MC 3486
SN 75 ALS 193
SN 75 ALS 195
We recommend not to exceed the cable length related to the scanning frequency, since otherwise the
switching times resp. the edge gradient cannot be maintained.