Metrohm 838 Advanced Sample Processor Manual - Manual (Page 15)

2.1 Operating principles
Metrohm 838 Advanced Sample Processor, Operation 7
Important:
For safety reasons it is only possible to rotate the sample rack when
the lift or both lifts are located in the shifting position or above it. Dur-
ing a rack rotation the lift (or both lifts) are automatically first raised to
the predefined shift height.
When a method is started a second time, without switching off and on
again, the last accessed sample position is memorized and be ap-
plied in the next method run.
9
LIFT
Raises or lowers the lift. The predefined lift positions (working position,
rest position, rinsing position, shifting position, special position) can
be selected with the <SELECT> key. They can be entered and
saved separately for each rack in the configuration menu.
As well as the predefined lift positions it is also possible to enter abso-
lute lift positions in mm via the numerical keys.
PUMP
4
The <PUMP> key is used for switching the peristaltic pump. The
pump rate can be selected in 15 steps. Selecting a sign (+ or –) with
the pump rate allows to set the direction of the rotation of the pump
drive.
Under <PARAM>, >manual stop you can define whether the peri-
staltic pump should be switched off with the <STOP> key or not.
5
STIR
The <STIR> key is used for controlling the stirrers. A stirrer can be
switched on permanently or switched on for a given period and then
switched off again. The <SELECT> key is used to select both the
stirrer and the function. The current status of the stirrer is shown di-
rectly in the display.
Example:
STIR: T1 : ON s Display: STIR +- (+=on -=off)
STIR: MSB2 : 10 s Display: STIR 10 s
In this case in the first line the stirrer at tower 1 is switched on. The stir-
rer is selected with the <SELECT> key. As can be seen in the sec-
ond line, the duration of the stirring process can also be entered.
The stirring rate can be set for each stirrer in the parameter menu.
Under <PARAM>, >manual stop you can define which stirrers can
be switched off with the <STOP> key.
DOS
6
The <DOS> key is used to control the connected dosing devices.
Both positive and negative volumes can be dosed. Negative volumes
are used for aspirating liquids, e.g. during pipetting.
As well as entering the volume to be dosed (with the numerical keys),
<SELECT> can also be used to select additional functions:
- Filling the dosing or exchange unit (fill)
- Initializing the exchange of a Dosing unit (release)
- Preparing the tubing systems and cylinder (prep.)
- Emptying the tubing system and the dosing cylinder (empty)
- Ejecting the cylinder contents (Eject)