TEC HV TEST STAND LOG

Auxilliary Tests

Prior to the normal suite of tests, the 1469 modules were set (at default trip currents) to 3500 volts, without loads, for several hours.  Tbis was done to assure that an infrequent trip problem noted in the prototypes was no longer present in the new modules.

Test date:  2-4 March, 1999
Test Adminsitered by :  Achim Franz and Ryan Roth                          Number of Modules Tested:   8 (1 - 8)
Module Type:  1469P                                                                                      Sub-System:  TEC
Test Database Name:   03.03.09.29.17                                                       Test Database FileName:  03.03.09.29.17.TheDB.DB

Long Term Test Run From   March 3 09:40:11 to March 4 10:12:42      LT Voltage = -3500V

Non-Load LT Channel Trip = -0.25 uA                                                 Non-Load LT Bulk Trip = -10 uA

Load LT Channel Trip = -5 uA                                                              Load LT Bulk Trip = -40 uA
 

Module Serial#        Channel Name    Errors?     Set Aside?   LT Load?
**************************************************************************
B51209                Bulks 00 - 02    No           No           No
                      Chans 00 - 23    No

B51067                Bulks 00 - 02    No           No           No
                      Chans 00 - 23

B51138                Bulks 00 - 02    No                        No
                      Chans 00 - 23

B51207                Bulks 00 - 02    No           No           No
                      Chans 00 - 23    No

B67769                Bulks 00 - 02    No           No           No
                      Chans 00 - 23

B67746                Bulks 00 - 02    No                        No
                      Chans 00 - 23    No

B51132                Bulks 00 - 02    No                        No
                      Chans 00 - 23    No

B51074                Bulks 00 - 02    No           No           Yes
                      Chans 00 - 23

**************************************************************************

Notes:

  1. Testing these modules uncovered some problems with the EPICS and HV software which had previously escaped notice.  As a result, considerable time was taken to go over these modules and the code.  In addition, the long term test was run for more that 24 hours.  The problems were related to an infrequent interruption of VxTasks on the IOC which eventually caused a crash.  Modules with large number of channels seem to be especially prone to this.  The problem is still under investigation, but it has been determined that it is not caused by these modules specifically.
We have found that, when testing 1469s over long periods without loads and with low (~0.25 microAmp) Trip Currents, the channels can infrequently trip.  In this case, this behavoir was restricted to the modules B51067, B51138, B67746, and B51132.  The plot of the 14 affected channels are shown below; two bulk supplies also tripped, but, as their information is not stored in the database, it is not shown here (each bulk suppy only tripped once or twice over the entire testing period, and so is not considered significant).  Note that the long term testing software stops enabling a channel after it trips more than 20 times -- here this occured for three channels:  B51132_09, B51138_10, and B51067_23.



The following modules were retested with loads and then passed as not having a significant problem:  B51067, B51132, B51138.

Test date:  25-26 March, 1999
Test Adminsitered by :  Achim Franz and Ryan Roth                          Number of Modules Tested:   6 (9 - 14)
Module Type:  1469N                                                                                    Sub-System:  TEC
Test Database Name:    03.25.09.36.40                                                    Test Database FileName:  03.25.09.36.40.TheDB.DB

Long Term Test Run From   March 25 11:42:13 to March 26 16:27:20    LT Voltage = -3500V

Non-Load LT Channel Trip = -0.30 uA                                                       Non-Load LT Bulk Trip = -10 uA

Load LT Channel Trip = -5 uA                                                                      Load LT Bulk Trip = -40 uA
 

Module Serial#        Channel Name    Errors?     Set Aside?   LT Load?
**************************************************************************
B67767                Bulks 00 - 02    No           No           No
                      Chans 00 - 23    No

B67734                Bulks 00 - 02    No           No           No
                      Chans 00 - 23

B67741                Bulks 00 - 02    No           No           No
                      Chans 00 - 23

B67763                Bulks 00 - 02    No           No           No
                      Chans 00 - 23    No

B51079                Bulks 00 - 02    No           No           No
                      Chans 00 - 23

B67752                Bulks 00 - 02    No           No           Yes
                      Chans 00 - 23

**************************************************************************

Notes:

  1. There were no problems with the short-term tests of these modules.  In addition, there was a very low occurance of trips during the long-term test.  It is known that the 1469s tend to trip frequently during the long-term test because of the lack of load and the low trip current setting.  Here, the trip current setting was rounded up to -.30 microamps (this was done by the module software), resulting in a much lower trip occurance.  Only four channels tripped during the long-term test, with a maximum of five times.  Here are their plots:


TEC 1469 Long Term Trips

Test date:  26 April, 1999
Test Adminsitered by :   Ryan Roth                                                           Number of Modules Tested:   4 (1-4)
Module Type:  1471N                                                                                    Sub-System:  TEC
Test Database Name:    04.26.09.15.50                                                    Test Database FileName:  04.26.09.15.50.TheDB.DB

Long Term Test Run From  09:37:01 26 April to 09:18:25 27 April          LT Voltage = -4800V

LT Regular and Peak Trip Current = -7 uA                                                LT Loads = 1 GigaOhm

Module Serial#        Channel Name    Errors?     Set Aside?   LT Load?
**************************************************************************
B68016                Chans 00 - 07    No           Yes(1)       Yes

B68006                Chans 00 - 07    No           No           Yes

B68015                Chans 00 - 07    Yes(2)       No           Yes

B68142                Chans 00 - 07    No           No           Yes

**************************************************************************

Notes:

  1. This module possessed a HVL of -5055 V -- it will be sent back to Physics to be remodified to a HVL less than 5kV.
  2. Channel B68015_04, during the intial part of the long-term test, consistently had a Peak Current trip (15 times).  However, after about 4 hours under voltage, it never tripped again; it seems to be functioning normally now, so it will not be set aside for repair.  A graph of its voltage and current are shown below:
TEC1471_1.gif
 Test date:  27 April, 1999
Test Adminsitered by :   Ryan Roth                                                           Number of Modules Tested:   4 (5-8)
Module Type:  1471N                                                                                    Sub-System:  TEC
Test Database Name:    04.27.09.39.18                                                    Test Database FileName:  04.27.09.39.18.TheDB.DB

Long Term Test Run From  10:00:05 27 April to 08:51:37 28 April          LT Voltage = -4800V

LT Regular and Peak Trip Current = -7 uA                                                LT Loads = 1 GigaOhm

Module Serial#        Channel Name    Errors?     Set Aside?   LT Load?
**************************************************************************
B68139                Chans 00 - 07    Yes          Yes(1)       Yes

B68033                Chans 00 - 07    Yes          Yes(2)       Yes

B68369                Chans 00 - 07    No           No           Yes

B68356                Chans 00 - 07    No           Yes(3)       Yes

**************************************************************************

Notes:

  1. Channel B68139_01 frequently reported a voltage 3-4 Volts greater than demand, while its MVDZ was set to 1.1 Volts.  In addition, channel B68139_05 consistently tripped during the long term test, giving first peak current trips, then voltage supply limit trips then finally settling on voltage change rate trips.  This module will be sent back to LeCroy for repair.
  2. Channel B68139_00 reported a voltage of -41.3 V when the HV was on and the Demand Voltage set to zero.  It will be sent back to LeCroy for repair.
  3. Module B68356 has an HVL that is about 70 V higher than the required 5kV satey limit, and is being re-modified.

    4. Due to a minor problem, the HV was shut off for a period of less than ten minutes during the long-term test.  Because of this, the test database will record that the voltages of all channels dropped to near-zero for one event.  The test was restarted immediately and allowed to run longer than usual to make up for the mishap.  Eventually, the erroneous readbacks will most likely be removed from the database.