BECKHOFF PT100 User Manual
Page 6
PT100 4-fold temperature measurement
Beckhoff II/O System
Page 6 of 10
Version : 1.1
Date : 12 March 97
Channels are pre-selected in accordance with Select 1-4 priorities.
Select1
Select2
Select4
Significance D0, D1
0
0
0
Measurement channel 1 is
selected.
1
0
0
Measurement channel 2 is
selected.
0
1
0
Measurement channel 3 is
selected.
1
1
0
Measurement channel 4 is
selected.
0
0
1
Control channel a is selected.
1
0
1
Control channel b is selected.
Pre-selection is valid with the falling edge (1=>0) of signal "Valid" D2.3.
Control channels a and b provide a specific bit pattern at selection. This allows for monitoring
of whether or not the microprocessor is active and properly operating.
Set value for control channel a: AA55 hex
Set value for control channel b: 55AA hex
The processor may be restarted by means of the D2.7 reset key if this alternating bit pattern is
not provided.