Release Note 149.0
The Specification of Logged Data
Robert E. West
August 14, 1995
This document describes the first part, the EPICURE data logging editing utility for specifying the devices from which data is to be collected and recorded.
A user interacts with the data logging editing utility via a menu interface implemented using the EPICURE Screen Management (ESM) software. Standard conventions of an ESM menu interface are the following:
A data collection and recording process may be executing on each of multiple VAX nodes. Each data logging process has its own set of device parameters and its own file for recording the data. The user identifies the desired set of device parameters by selecting the name of the VAX node on which the data logger is executing.
Each data logging process has six data acquisition lists with each list collecting data at a different rate or at a different time in the accelerator cycle. A rate or time is specified by a frequency time descriptor (FTD). For example, a rate of every 10 seconds is represented by an FTD of R10.0. Once per accelerator cycle at 4 seconds after the occurrence of phase clock event 5 is represented by an FTD of T5+4.0. The assignment of FTDs to data acquisition lists is controlled by system parameters which the user is not able to modify. The user specifies a data acquisition list by selecting the associated FTD from the assigned set.
The user selects the item READ from the OPERATIONS menu to input and display the device names contained in the file associated with the specified data logger and acquisition list. The total number of devices in the file which are marked for logging is displayed in the upper right portion of the screen. The device names are displayed in four vertical sections with 15 devices in each section. Three fields are displayed for each device: (1) a flag indicating whether or not data collection and recording is to be done for this device, (2) the device's name, and (3) indicators for the reading, setting, and status properties of the device.
Columns on the display containing the property fields are labeled with "RET". "R" stands for Reading, "E" stands for sEtting, and "T" stands for sTatus. A period under one of these letters indicates the device has no such property. An underscore indicates the device has this property but it has not been selected to be logged. An asterisk indicates this property is to be logged.
If there are more than 60 devices in the file, then it is necessary to move from one display screen to another. To move to the next screen, position the cursor over the N in the upper right corner immediately below the menu bar and double click mouse button #1. To move to the previous screen, position the cursor over the P in the upper left corner immediately below the menu bar and double click mouse button #1. In the upper right portion of a screen is displayed the number of this screen over the total number of display screens.
There are a maximum of three screens. Each screen may display a maximum of 60 devices in 4 columns with 15 devices in each column. A maximum of 180 device names may be specified for a single data acquisition list. Since it is possible that each device may have the three properties of reading, setting, and status, a maximum of 540 device accesses may be executed by a single data acquisition list.
A data collection file is a circular file with a section allocated for each of the six data acquisition lists. After some period of time, the oldest data in a section is going to be overwritten by the newest data. This period of time is called the duration of the data acquisition list and is displayed in the upper right portion of a screen. The duration is a function of the size of the area on disk, the number of devices and properties which are being logged, and the rate at which they are being logged. Changing the logging status of a device or property or adding or deleting a device changes the number of logged devices and the duration of the list.
Columns on the display containing the logging flag fields are labeled with "No". The usual entry in this field is an X, meaning no logging of the device name is to be performed. If the field is blank, data for the device will be collected and logged. Positioning the cursor in this field and double clicking mouse button #1 toggles the field contents between blank and X, blank meaning log and X meaning don't log. This field may also be over-typed with a blank or an X. Input is terminated by pressing carriage return or double clicking mouse button #1.
A displayed device name is modified by positioning the cursor over the name and over-typing. The keyboard input is terminated by pressing carriage return or double clicking mouse button #1.
The property field contains three columns. The left column is for the reading, the center column is for the setting, and the right column is for the status. A period in a column indicates that device does not have that property. An underscore indicates the property exists but it has not been selected to be logged. An asterisk indicates the property has been selected. Positioning the cursor in a property's column and pressing carriage return or double clicking mouse button #1 toggles the logging indicator between an asterisk and an underscore. If a device has only one property or only one has been selected, then no toggling is done, i.e., the asterisk is not changed.
The user saves the modified list of devices by selecting SAVE from the OPERATION menu. The disk file associated with the selected data logger and acquisition list is then updated with the new information. However, the data acquisition list being executed by the logging process is not updated with the new information. Selecting RESTART from the OPERATION menu stops the currently executing data acquisition list, builds a new data acquisition list using the information in the associated disk file, and then starts the new list. A reply box appears on the display screen when the data logging process completes processing the RESTART request.
The set of device names being displayed may be saved to a user's own file by selecting FILE from the OPERATION menu, entering the name of the file in the dialogue box, and then selecting SAVE from the next dialogue box, The device information is then written to a new file with the specified name. Conversely, device information may be accessed from a user's file by selecting FILE from the OPERATION menu, entering the name of the file in the dialogue box, and then selecting READ from the next dialogue box. Normally, a file read in this manner is one which has previously been output by the data logging editing utility and therefore contains all the expected information. However, the utility can also input a file containing only device names. In this case, the device names are consecutively displayed on the screen and the first existing property of each device is flagged for data collection and logging. The properties are examined in the order of reading, setting, and then status. A file of selected device names extracted using the EPICURE data base reporter utility may be used to generate the corresponding data logging device file by selecting the FILE entry from the OPERATION menu.
The menu bar across the top of the workstation window contains the following items:
After an item is selected from this menu, the FTD and the number of the associated data acquisition list are displayed in the header of the display. This menu is displayed after the selection of a logger.