Bruker BMPC/2, Technical Manual

Page: 35 / 136

35 Z31823_00_05
Software
5.5 Automatic Pump Test
The Automatic Pump Test is a software activated test used to ensure that the second
pump is operational. During normal operation only one of the BMPC/2 vacuum pumps is
needed, the other pump is only required in the event of a malfunction. To ensure correct
operation, the second pump should be tested on a regular basis using the Automatic
Pump Test.
During the pump test the spare pump replaces the active pump and the P1 pressure and
F1 helium flow are monitored. When the pump is working correctly, these parameters
should only deviate within a given range.
To prevent false alarms during the automatic pump test, all alarms are temporarily
disabled.
i
The automatic pump test is only possible if the BMPC/2 is running in automatic mode!
5.5.1 Description of the Test Cycle
The automatic pump test consists of the following series of events:
1. The spare pump is switched on.
2. The helium flow is monitored for 1 minute.
3. When the pump is operating correctly, a short increase in the helium flow can be
seen and the test will proceed to the next step.
The spare pump‘s valve should now be open and the original valve closed. The
pump under test is now working, but the original pump is also still operating.
4. The pump will run for a minute until the values for P1 and F1 have restabilized.
5. After the values have stabilized they will be monitored for a minute. When both
parameters do not deviate more than +/- 15% from the original value than the
pump
test is successful
.
6. After a successful test the valves are switched back to their original position, and
after a 15 second delay, the pump under test is switched off.
The original pump should be running and a decrease of the helium flow should be
observed. This decrease is due to a backflow of gas between the helium flow sen-
sor and the pump under test and its valve.
7. The cycle is complete after another minute when all the values have stabilized.
When a
problem occurs
during the automatic pump test the test cycle is immediately
aborted and the original pump configuration restored. An error message is then dis-
played in the information window and in the event log.