Software Manual Freedom EVOware Standard 2.3 Freedom ...

14 - Advanced Programming Features for Scripts
Variables and Expressions in Scripts
14.1.4.13 RACK_OFFSET
This variable lets you modify the labware selection for the basic commands
Aspirate, Dispense, Mix and Move LIHA. If e.g. RACK_OFFSET equals 1,
Freedom EVOware searches for the next labware of the same type on the
worktable. The search direction is from rear to front of the worktable and then from
left to right. Negative values in RACK_OFFSET cause Freedom EVOware to
search in the opposite direction.
Set RACK_OFFSET to 0 to deactivate the offset.
14.1.4.14 RACK_VOLUME_x
The Te-MO, the MCA96 and the MCA384 do not support liquid level detection. If
you want to use a liquid class for these pipetting arms which specifies liquid level
detection, the liquid level must be emulated. To do this, specify the well volume
(well capacity) of the labware you are using by assigning a value to this variable.
Replace the X in the variable name with the labware label (labware name), e.g.
use RACK_VOLUME_SOURCE if you named the labware SOURCE. For
mechanical reasons, the same volume is pipetted by all of the tips.
Instead of setting this parameter to the well volume (well capacity), you can use
the LiHa command Detect Liquid before you aspirate with the Te-MO, MCA96 or
MCA384 to detect the actual liquid level in one of the wells. Then copy the value
reported in the DETECTED_VOLUME_x variable to the RACK_VOLUME_x
variable (see 14.1.4.2 “DETECTED_VOLUME_x”, 14-5).
Liquid level detection can be used e.g. to ensure minimal tip contamination by
limiting the tip immersion depth. The Te-MO and MCA96 only use the emulated
liquid level detection for aspiration. The MCA384 uses it for dispensing, too. The
value of the RACK_VOLUME_x varable is not updated by subsequent pipetting
commands, even if they affect the volume of liquid in the wells.
14.1.4.15 REPLACE_DITI_GRID
If you are using DITIs, Freedom EVOware provides special facilities to ensure that
sufficient DITIs are present on the worktable for your script or process and to
automatically fetch new DITI racks as and when needed.
For each Get DITI command in your pipetting script, Freedom EVOware
automatically sets the two variables REPLACE_DITI_GRID and
REPLACE_DITI_SITE to the correct grid and site for the selected DITI type before
executing the command.
If your script includes an Activate DITI Handling command and all of the DITIs in
the rack have been used, Freedom EVOware calls the DITI replacement script
which is specified in the command. The replacement script is normally
implemented using one or more Transfer Labware commands
The worktable location of the DITI rack which needs replacing is specified in the
replacement script with the variables REPLACE_DITI_GRID and
REPLACE_DITI_SITE.
These two variables are only used by the automatic DITI handling feature in
Freedom EVOware Standard. Freedom EVOware Plus uses a different concept
for automatic DITI handling.
See 17.1 “Using the Automatic DITI Handling feature”, 17-1) for more
information.
Freedom EVOware Software Manual, 393172, en, V2.3 14 - 7