Metrohm 843 Pump Station with membrane pump - Manual (Page 28)

7.2 Remote interface
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843 Pump Station with Membrane Pumps
Note
Before utilizing any particularly aggressive media, it is imperative that
you determine whether or not the materials mentioned above are
resistant to them
In addition, the membrane pump has an exceptionally long service life.
The only parts subject to wearing are the membrane and the valve plates.
The dosing precision of the membrane pump is significantly enhanced by
a valve (see Figure 3, page 7) on the pump outlet. This is responsible for
the following three functions:
￭ Pressurizing function
The pressurizing valve ensures constant backpressure while conveying
in systems with fluctuating pressures, in a vacuum or out of a depres-
surized area.
￭ Overflow function
The valve prevents non-permitted high rises in pressure in the pressure
system.
￭ Anti-injector function
The pressurizing valve prevents the occurrence of an injector effect
(aspiration of outside air caused by negative pressure) while dosing in
tubing systems with high flow speeds.
7.2 Remote interface
7.2.1 Pin allocation of the remote interface
1
5
6
9
5
1
9
6
Figure 11 Pin allocation of remote socket and plug
The above pin allocation display applies for all Metrohm instruments with
9-pin D-Sub remote connectors.
The two remote interfaces are linked with one another in the instrument.
Various signal lines are looped through from Remote 1 to Remote 2,
without executing a function in the instrument.