POSITIP 855 - heidenhain - DR. JOHANNES HEIDENHAIN GmbH

II - 5 Measured Value Output
Starting measured value output
Starting measured value output over external switching input
You can start start measured value output over the switching input
at the D-sub connection EXT by sending a pulse or by making
contact.
Contact at pin 9: make contact against 0 V
Pulse at pin 8: pulse duration te ³ 1.2 µs
The contact or pulse can also be sent over a TTL logic device
(such as SN 74 LS XX):
U H ³ 3.9 V (U MAX = 15 V)
U L £ 0.9 V with I L £ 6 mA
te: Minimum duration, pulse
te ³ 1.2 ms
te: Minimum duration, contact
te ³ 7 ms
t1: Delay between pulse and internal latch
t1 £ 0.8 µs
t1: Delay between contact and internal latch
t1 £ 4.5 ms
t2: Delay between internal latch and measured value output
t2 £ 30 ms + (5 ms · N)
N = number of rotary axes with Deg/Min/Sec display
t3: Delay between end of data output and next latch over
external switching input
t3 ³ 0 ms
tD: Duration of measured value output
The duration of measured value output (tD) depends on:
• The selected baud rate (BR)
• The number of axes (M)
• The number of blank lines (L)
tD =
176 · M + L · 11
[s]
BR
Fig.47: Time diagram for measured value
output over external switching input
POSITIP 855 Technical Information 103
PIN 9
PIN 1
(0V)
EXT
EXT
PIN 8
PIN 1
(0V)
Fig.46: Signal by make contact against 0 V or
by pulse
TXD
t e
t 1
t 2
t D
t e
t 3