Release Note 158.0
The Display of Logged SWIC Data
Robert E. West
January 17, 1997
The EPICURE SWIC data logging process reads SWIC scan data every cycle and writes it to disk for later display and analysis. Fifty-one SWICs are currently being read starting at 12 seconds after event T6. To change which SWICs are read, the input list of SWIC names is modified by an appropriately authorized person of the control system group and then the SWIC data logging process is restarted. At approximately midnight, the SWIC data logger closes its current data file and opens a new file. The filename format is DATA-dd-mmm-yyyy.DAT, where dd is the day of the month, mmm is the month, and yyyy is the year. If all 51 SWICs return data every cycle, the size of each data file exceeds 72 megabytes or 148,000 disk blocks. This amount of SWIC logging fills 80% of a 9 gigabyte disk in approximately 100 days.
Logged SWIC data is displayed using the application executed by the entry "Display Logged Swics" (#33) on the general EPICURE menu. The user interface of this application is very similar to that of the SwicDisplay application (#31) used to display data currently being read from selected SWIC modules. No voltage or position information is logged for the SWICs, so these fields of the display are not significant. This application does not communicate with any hardware modules, so no values can be set.
Above the area for the first SWIC on the display are two additional fields: starting time and frequency. The starting time of the desired logged data is entered in the box next to the string STARTING TIME using the standard format of dd-mmm-yyyy hh:mm followed by a carriage return. When a valid entry is made in this field, the display application will next retrieve data starting at or after this time. The starting time of the next data to retrieve is only reset when this field is updated. In all other cases, the time of the next data to retrieve is one cycle later than the time of the previously retrieved data. The frequency of display is entered in the box next to the string FREQUENCY. No logged data is accessed until a value is entered in this field. A frequency value of 1 to 60 means display the next cycle of data every n seconds, where n is the entered value. A frequency value of 0 means display the next cycle of data and then wait for the next input from the user.
The specification of SWIC names is the same as that used by the application which displays SWIC data currently being read from the modules. Any SWIC may be selected from the list of available SWICs, but not all are being logged. If there is no logged data for the specified starting time, a data pending message is displayed.
The following SWIC modules are currently having their scan data read each cycle and saved on disk for later display and analysis: