Merck Millipore Mobius Chrom 20 System User Manual page 91

Mobius Chrom 20 System with Flexware
®
Set the system to Global Auto and Default (Step 1 & 2) at the start of an operation, to ensure
that the status of components is known.
CAUTION Valves that have been manually forced (not set on Auto) will not be affected by
the System Default. Having the Global Auto step or clicking the All Auto button
may be used to set the valves to Auto, but always visually check the Process
Display to make sure that all valves are in their correct state before executing an
operation!
Next, the flowpath is defined (Steps 3–6), starting from the inlet and moving sequentially to
the bubble trap, column and finally the outlet. Having established a valid flowpath, the pump
parameters are set (Steps 7–8). It is important to set these before starting the pump. Finally,
the pump is started (Step 9).
The steps use a step time of 2 seconds to allow their occurrence at discrete times rather than
rapidly one after another (see below).
Note The computer is faster than hardware such as pumps and valves. Allow adequate time
(1 or 2 seconds minimum) for an action to take place before proceeding to another step.
This holds true for the end of an operation. If you specify that a valve closes at the
end of an operation, the computer may send this command, and then end the operation
before the last action (valve closing) physically takes place. You may specify None as the
last action, and list a wait time as the criterion, or select Go to Default as the final action
to ensure that all actions have completed. It is good practice to use Go to Default at the
start of an operation.
When operating the system in flow control mode, allow adequate time for the flow rate
to stabilize, prior to bypassing the bubble trap. The system will automatically hold the
pump at the same speed it is operating at when the bubble trap is bypassed. This is
because the control will become unstable when not using the bubble trap.
Assemblies
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