Agilent Technologies 8453 User Manual, Installing And Operating Manual page 105

Table 26
Position Encoder, 7-Segment Drivers, Position LED
An encoder wheel on the axis of the valve and three light switches provide a
three bit signal for the 8 possible positions of the valve. The actual position of
the valve is displayed on the front panel by the position LED which is driven
by 7-segment drivers. A fourth light switch is used to sense the fine
positioning (position line is "1" if setpoint position is reached). (These lines
can be accessed, opening the valve-pump controller-valve cable.)
Table 27
Position
Agilent 8453 Dissolution Testing System Installing and Operating Manual
Valve Position Lines (assuming the valve unit is connected and addressed)
(continued)
D2OUT D1OUT
D2IN D1IN
7 1 1
8 1 1
Encoder and Position Lines
Encoder Encoder
Bit 2 Bit 1
1 0 0
2 0 0
3 0 1
4 0 1
5 1 0
6 1 0
7 1 1
8 1 1
Using the Valve Unit and Valve-pump Controller
Servicing Your Valve System
D0OUT
D0IN
0
1
Encoder
Bit 0
0
1
0
1
0
1
0
1
4
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