Metrohm 746 VA Trace Analyzer - Manual (Page 553)

7 Safety, Errors, Troubleshooting, Diagnosis, GLP
746 VA Trace Analyzer / 747 VA Stand
7-54
7.6.7 Checking the VA Stand
(performing measurement routine with program simulator)
1 Prepare instrument for diagnostic test (see section 7.6.2).
2
3 press several times and check the on/off switching of the valve
4 press several times and check the on/off switching of the valve
5 press several times and check the on/switching of the motor
The VA Stand includes a dummy cell and a polarogram simulator. In polarography,
this polarogram simulator replaces the electrochemical system (sample, electrode)
and thus performs extremely valuable service if a malfunction occurs to allow the
user to decide whether the malfunction is traceable to the instrument or the electro-
chemical system. This simulator can naturally also be used to practice operating
the instrument.
In the factory a special test method is stored in the VA Stand. This test method
TEST747.mth is written for the polarogram simulator and allows virtually 100% con-
trol of the entire measurement system.
Should the test method be deleted by accident, a new one can be generated with
the aid of the enclosed program sequences.
6 Copy test method TEST747.mth to working storage.
•
• Position cursor on TEST747.mth .
• ,
7 Define sample size.
•
• Position cursor on Sample size/S0 .
•
• < * >,
8 Start TEST747.mth method.
•
The message AE->AE / RE->RE appears on the screen.
• Attach electrode cable AE to clamping screw AE.
• Attach electrode cable RE to clamping screw RE.
•
The message WE -> WE-L appears on the screen.
• Attach electrode cable WE to clamping screw WE-L.
•
The message WE -> WE-D appears on the screen.