FID User's Guide
JACK C. SCHMIDT
.5cm The Cryogenic Controls System has undergone massive changes since the last Experimental run. The Apple personal computers have been replaced with VAXstations that communicate with the multibus through a VME interface. This upgrade has brought about the redesigning of application software needed to control the cryogenic systems.
The new FID (Frig Interactive Display) application was designed after reviewing the advantages and disadvantages of the Closed Loop applications available on the Apples and on the ACNET system. Diagram 1 shows the FID screen. The screen layout was designed with the KISMIF (Keep It Simple, Make It Fun) principle in mind. All loop information returned from the multibus is displayed on the screen and menus have been implemented to make the application user-friendly. Loop values may now be stored to a file and recalled at the users request.
The input of loop data has changed greatly from the Apple system. There are no USC commands. The user has full control over the screen and isn't required to learn complex abbreviations to set loop elements. The user locates the cursor over a settable field, types in new information, and enters a carriage return to send the information to the front end. The new value will be left justified and displayed in bold video. When the front end responds with new readback, the data is right justified and displayed in the settable field. If a carriage return is not entered, the settable field is overwritten with data from the front end as soon as the user moves the cursor out of the settable field. Loop selection is achievable by either menu selection or typing in a new name in the appropriate field on the screen and entering a carriage return. In both instances, the program accesses the loop file for the appropriate record and converts the input and output device names to TANS. These TANs are compared to the TANs returned from the front end. If they match, the text names stored in the file are written to the device name fields; if there is a mismatch, the front end TANs are displayed.
Menus have been added to the FID application to create a user-friendly environment. To access the menu bar (line 2 of the FID screen) press the Do key or click on the menu with the mouse. Menu movement in the horizontal and vertical menus is accomplished by the arrow keys or by positioning the mouse over the field and clicking. Menu item selection is accomplished by entering a carriage return or by double-clicking the mouse. To exit a menu without making a selection, press Ctrl-Z. Copies of the FID screen at the end of this document show the menus available to the program user.
The menu bar contains six items that allow the user access to specific functions of the FID application. list [Page] When selected the Page option displays a pulldown menu of items that deal with the screen. [Multibus] Selects which multibus will be accessed for data. A multibus must be selected before a loop is chosen or an error message will result. [Loops] When selected puts up a pulldown menu with the twenty loops listed for that multibus. This allows the user to switch loops without having to type in a new loop name. [Mode] This is a new feature of the FID application. A pulldown menu is displayed with four choices, allowing the user to select a particular type of loop along with the loop number. [Print] Lists the print queues available and routes a copy of the screen to the chosen queue. [Exit] Exits the FID program and returns the user back to the calling environment.
The Page pulldown menu displays four choices (Dia 2). These allow the user to save and restore loops to files and to display stored file information when necessary. list [Restore] Downloads file information for displayed loop and mode to the multibus. [Save] Saves current screen to a record in a file. Record is based on loop number, multibus number, and mode. [Compare] Displays the file information on the screen in inverse video along with the current multibus values (Dia 3). [Normal] Removes the file information from the screen.
The mode pulldown menu allows the user to select one of four running modes for the loop (Dia 5). This refers to information stored in the records and not what is actually at the front end. By selecting a new mode the user is able to access file information pertinent to that loop . list [Cooldown] The cooldown mode is for tuning a loop during a cooldown. [Intermediate] When a cryogenic system is between cooldown and normal running modes it is said to be in the intermediate mode. [Normal] This mode contains the values a loop should operate at under 'normal' conditions. [Test] This mode was created to let the operator 'play' with a loop and save the values.
The FID screen consists of five types of display fields: text entry, text display, toggle, numerical entry and numerical display. Cursor movement between fields is accomplished by use of the arrow keys (one cell at a time) or by defined keys that allow settable field jumping ( pf3 --- next field, pf4 --- previous field), or by locating the mouse over the field and clicking.
Loop gains are now settable. If a user adjusts a gain, the user will notice a change in the appropriate k-factors. If a user changes a k-factor, the user will notice a change in the gain values. The gain and k-factor settings are based on the following equations:
eqnarray* PG & = & -(K_1 + 2K_2)
IG & = & K_0 + K_1 + K_2ST
DG & = & K_2 ST
K_0 & = & PG + IG ST + DGST
K_1 & = & - PG - 2 DGST
K_2 & = & DGST eqnarray*
Notice that these equations will not produce linear results. In other words, if PG is changed, new K0 and K1 values will be calculated. If K0 is changed, then IG will be recalculated, not PG.
Errors that occur with data acquisition from the front end will be displayed in abbreviated format in the field affected. The following is a list of common errors and what they mean.
list [LESSDATA] The multibus has returned less information than the Closed Loop application expected to see. If this error occurs, try entering the loop name again. If the error continues, call one of the computer people. [MOREDATA] The multibus has returned more information than the Closed Loop application expected to see. If this error occurs, try entering the loop name again. If the error continues, call one of the computer people. [TBLRNGERR] The returned data information is outside the range table defined in the database. Adjusting the loop settings will remove this error.