3 process control – Metrohm 774 Oven Sample Processor User Manual

Page 41

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3.3 Methods and Sequences

774 Oven Sample Processor, Instructions for use

35

The LEARN function is available for the following commands:

Command Adaptive parameter

Type of function


LIFT

Lift position in mm

absolute

WAIT

pause time in seconds

additive

DOS

Dosing volume in mL

additive

SCN Rm

Status of the 8 remote lines

"live" value

SCN RS

Received character string

"live" value


TRACE function

The "TRACE" function is a valuable aid for processing a complete sequence
or method, or excerpts, step-by-step for test purposes. Each command line
in a sequence can be carried out directly by pressing the <START> key.
When the action is finished the following command line is displayed.
"Tracing" can be used directly after the entry of a command line or at any
time after the parameter menu has been opened and a sequence has been
selected.

3.3.3 Process control


<START> is used to start a method from the normal state. If not inter-
rupted manually and if no unexpected errors occur the sample series will be
processed properly and terminated with the final sequence. The sample
sequence is carried out several times according to the entry in 'No. of sam-
ples', starting with the sample beaker which has been defined as 'SAM-
PLE
'.

If the sample series is interrupted with <STOP> the Oven Sample Proces-
sor immediately returns to the normal state. Unprocessed samples are not
taken into account; the final sequence is not carried out. If settings for this
occurrence have been entered under '>manual stop' then the correspond-
ing actions or commands will be carried out via the interface in order to
stop the connected instruments as well or to carry out other actions.

The sample series can also be interrupted with <HOLD>. The command
which is currently active is immediately terminated. <START> can be used
to continue the method with the following command in the sequence which
is active. Connected peripheral units are not stopped with the <HOLD>
key. In the 'HOLD' condition the current oven temperature is maintained.

<CLEAR> interrupts a sample series when the currently active sequence
has ended (soft termination). The sample which is currently being proc-
essed will be processed to the end.

<QUIT> terminates the command currently being carried out and starts
the next command line of the sequence.

If errors occur during a sample series then a corresponding error mes-
sage
will appear; this must be confirmed with <QUIT>. The sample
changer then goes to the HOLD status (see above). When the error has
been remedied <START> can be used to continue or, if necessary,
<STOP> can be used to terminate the sample series completely.
If the gas flow limits are exceeded or undercut this does not interrupt the
method sequence. The gas flow can be corrected manually with the gas
flow regulator.

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