HEIDENHAIN PT 855 for Milling - Manual (Page 104)

II - 5 Measured Value Output
102 Technical Information POSITIP 855
Fig. 45: Time diagram for measured value
output with Ctrl B
II - 5
Measured Value Output
POSITIP can output measured values over the data interface.
Starting measured value output
There are three ways to start measured value output:
• Transmit control character to the data interface
• Send signal to switching input
• Signal from edge finder
The delay between the latch signal and measured value output
depends on the selected signal.
Transit time of encoder signals
After approximately 4 µs the encoder signals are present in a buffer
which is interrogated by the internal latch signal. The measured
value that is output is therefore the value that existed approximately
4 µs prior to the internal latch.
Starting measured value output with Ctrl B
t
1
: Delay between Ctrl B command and internal latch
t
1
£ 0.5 ms
t
2
: Delay between internal latch and measured value output
t
2
£ 30 ms + (5 ms · N)
N = number of rotary axes with Deg/Min/Sec display
t
3
: Time between end of data output and next latch with
Ctrl B
t
3
³ 0 ms
t
D
: Duration of measured value output
The duration of measured value output (t
D
) depends on:
• The selected baud rate (BR)
• The number of axes (M)
• The number of blank lines (L)
t
D
= [s]
C t r l B C t r l B
t
1
t
3
t
2
t
D
R X D
T X D
BR
176 · M + L · 11