1. HAMILTON MICROLAB® STAR
Sequence Controlled Loops

2. Sequence Controlled Loops
Loop continuously until current position marker of controlling sequence goes past end position marker and is therefore set to zero
Main use to control loops when you don’t know the length of the controlling sequence in advance i.e
Number of positions in sequence used controlled by a user input "How many samples today?"
Sequence generated based on worklist

3. How to set up a Seq controlled loop
Select sequences that will be used in asp/dis steps in loop
If using fresh tips for each asp/dis step select tip sequence as well
Always set reset to never for tip sequence or tip seq will be reset after loop and method will try to pick up tips from positions that have already been used

4. Why include tip sequence
Enables the seq controlled loop to handle the situation where the last loop has less than 8 samples (on 8 channel instrument)
On last loop all sequences effectively set to same length as controlling seq
If controlling seq only has 4 positions left, tip sequence effectively set to have only 4 positions and 4 tips will be picked up

5. When not to include tip sequence
Do not include tip sequence in list of sequences to iterate over and adjust if keeping same set of tips on for loop (i.e dispensing buffer)
Can lead to the incorrect number of channels being used (see advanced user section for more details)

6. Examples
Transfer samples from one plate to another using new tips each time
Key Features
Include tip seq in seq controlled loop
Increment sequence on aspirate and dispense
Demo method seq_controlled_loops_demo_fresh_tips

7. Examples Adding buffer to plate using one set of tips Key Features
DO NOT include tip seq in seq controlled loop
No sequence increment on asp in order to reuse buffer reservoir
Demo method seq_controlled_loops_demo_one_set_tips

8. HAMILTON MICROLAB® STAR
Advanced Users section

9. How do seq controlled loops work
Start of loop
Checks condition for running loop is still valid i.e current position marker of controlling seq not zero
Sets Max property of each seq included in loop to the Max value of the SHORTEST sequence
Max is maximum number of positions available in seq
Max = (End – current) +1

10. How do seq controlled loops work
During loop
Perform asp/dis step using Max number of positions (if max>number of channels, uses number of channels positions)
Sequences incremented as per settings in asp/dis steps (Max is then recalculated at start of next loop based on new current position marker)

11. Example – transfer samples (fresh tips)
Example - What happens at the start of the loop
Before loop (Current/end/max)
Start of loop 1
(Current/end/max)
Source Seq (controlling)
1/20/20
Destination Seq
1/96/96
1/96/20
Tip Seq
1/192/192
1/192/20
8 Channel instrument

12. How do seq controlled loops work
Example - What happens during the loop
loop 1
Start (Cur/end)
Start
(Max)
loop 2
loop 2 Start (Max)
loop 3 Start (Cur/end)
loop 3 Start (Max)
loop 4 start
(Cur/end)
Source Seq (controlling)
1/20 20
9/20 12
17/20 4
0/20
Destination Seq
1/96
9/96
17/96
21/96
Tip Seq
1/192
9/192
17/192
Source, destination and tip seq incremented during asp/dis step in loop

13. How do seq controlled loops work
In loop 3, as Max is set to 4, only 4 tips are picked up and 4 positions used in source and destination sequences
At start of loop 4, condition to run loop no longer valid as current position marker of controlling sequence equals Zero.
Loop broken and loop 4 does not execute

14. How do seq controlled loops work
What happens if you include tip sequence in seq controlled loop but use same set of tips for loop.
Conditions that will cause a pipetting issue
Length of pipetting sequences must trigger a second loop
Tip sequence must be incremented
Number of tips in tip sequence, (End-current)+1, must between one and two times the number of channels used in the pipetting step.

15. Example – one set tips (tips seq included in seq controled loop)
Example – 8 channel instrument
loop 1
Start (Cur/end)
Start
(Max)
loop 2
loop 2 Start (Max)
Source Seq (i.e buffer)
1/8 8 1
Destination Seq (controlling)
1/24
9/24
Tip Seq
1/9
9/9
As tip seq included in the loop, Max of all sequences set to Max of shortest sequence at start of loop 2
As max is now 1, a single channel will be used to complete seq controlled loop
Destination seq and tip seq incremented during asp/dis step in loop

16. Examples – Using NTRs
When using NTR’s and GB NTR DirectUse library, putting tip sequence into loop doesn’t work
Example - transfer samples using new tips each time
Key Features
At start of loop get Max of controlling seq (SeqLib)
Create channel pattern based on Max using GB Create_Channel_Pattern library
Use gettips_channels step of NTR DirectUse library to pick up tips using channel pattern created

17. Examples – Using NTRs
Example - transfer samples using new tips each time
Demo method seq_controlled_loops_NTR_fresh_tips
Example – Adding buffer to plate using same set of tips
NTRDirectUse gettips_channels step outside of loop and channel pattern based on number of tips required
Demo method seq_controlled_loops_NTR_one_set_tips