Agilent Technologies 8453 User Manual, Installing And Operating Manual page 102

4 Using the Valve Unit and Valve-pump Controller
Servicing Your Valve System
Valve and Pump Actuation Electronics
Figure 42
The block diagram,
electronics of the valve unit for channel 1 only. Pumps are not shown.
Control Logic
The control logic of the valve-pump controller performs the handshake with
the spectrophotometer, and defines the timing for the valve actuation, and for
data-in and data-out lines.
The data valid line DV(-) and read/write line R/W(-) from the GPI0 port of the
spectrophotometer are used for handshake. A "0" on the read/write line
indicates a write cycle of the spectrophotometer, that is address and data are
written into the valve-pump controller, see
102
channel 1
pump
pump
select 1
drive
logic
valve
data in
latch
valve
select 1
DV (-)
R/W (-)
control
logic
rdy (-)
U1
data out
Valve and Pump Actuation Electronics
Figure
Agilent 8453 Dissolution Testing System Installing and Operating Manual
Agilent 89079A
+5V
pump on,
CCW
24VAC
direction,
CW
+5V
valve
run
position
manual
advance U2
comparator
position
42, shows part of the valve-pump controller and the
motor
switch
M
remote/
manual
switch
remote
LED
+5V
position
encoder
position
LED
7-segment
drivers
Figure 43.