Gradient function, Programming the pressure ramp (menu display) – Heidolph Hei-VAP Precision User Manual
Page 39

Operation
Operation
76
77
Copy data record
The data record is copied and saved under a new name. An entry of the new program
name will be required. A duplication of the issuance of the program name will be
checked.
Delete data record
Deletes the data record permanently.
Gradient function
A pressure ramp can be programmed with the gradient function, with which various
pressure values can be accessed. The respective pressures are controlled linear over
time. A pressure drop, i.e. by 50 mbar within 10 minutes, therefore results in a slight
increase of the pressure/time curve than the same pressure reduction in 5 minutes. The
maximum attainable increase of the pressure/time curve is limited by the pump capacity
and the leak rate of the system.
Rename the data record
The name can be entered similar to the “save” function. The system checks for
duplicates when naming.
Programming the pressure ramp (menu display)
The user can set the pressure and time in each line with gradient increments (but not the
sum time (total), since this is calculated automatically). The selected element is always
highlighted. The displayed gradient increments and the special elements on the right of
the menu entries are automatically scrolled upward and downward, since there is a total
of 20 gradient increments.
The currently selected entry (a pressure or a time) is called up by pressing the
Hei-GUIDE and the user can set the desired value by turning the Hei-GUIDE. Pressing the
Hei-GUIDE again will confirm the set value.
Entering and confirming value = “---” at “Vacuum” or “Duration” will delete the respective
values. The following value pairs slide upward by one increment.
Last increment with a value of > 0 at duration results in the total processing period.
1. The data record can be saved by using softkey “Store Favorite“ (1).
2. Softkey “Esc“ (1) discards the changes and returns to the actual value display.
3. The gradients can be entered in sub-menu “Enter pressure/time steps“.
4. Up to 20 gradient steps can be entered, whereby each gradient step consists of
pressure and time.
Heating bath
Setting of the bath temperature. Setting range is between
20 °C and maximum heating bath temperature (MAX TEMP is
adjustable in Setup) with a highest range of 210 °C.
Rotation
Setting of rotation speed of the distillation flask. Setting
range is between 10 and 280 rpm.
Max. power pump
Setting the maximum suction power of vacuum pump.
Setting range from 10 to 100%. A reduction of the suction
power results in a higher return rate of the solvent.
Hysteresis
Setting the pressure difference of the target value at which
the vacuum is re-adjusted. Setting range 1 – 50mbar
(only by using value controlled pump Rotavac valve control
or Rotavac valve tec, or House vacuum.)
Enter Pressure/Time
Steps
Changes the sub-menu for programming the pressure-time
ramps.
The pressure and time can be set in each line. However, the Sum of time
cannot be set, since this is automatically calculated.
The starting point is always at a time value of 0 and the atmospheric
pressure.
The following values can be changed in the menu view: