calc module Documentation

Release Notes

Records

aCalcoutRecord.html

The aCalcout record is much like the calcout record in EPICS base, but it supports array fields and calculations, and its output link can wait for completion.

sCalcoutRecord.html

The sCalcout record is much like the calcout record in EPICS base, but it supports string fields and calculations, and its output link can wait for completion.

transformRecord.html

The transform record is sort of like 16 calcout records collected together into a single record. The 16 calc expressions use a common set of 16 value fields, but each calc expression writes to its own value field.

swaitRecord.html

The swait record is much like the calcout record in EPICS base, but it uses an older form of retargetable links, and its output link waits for completion. The swait record is not recommended for new development; use a calcout record instead.

EPICS Databases, MEDM display files, and autosave-request files

arrayTest.db
arrayTest.adl

This database contains an aSub record that maintains two array fields: "$(P)arrayTest.VALA", and "$(P)arrayTest.VALB". The "VALB" field contains double values from 0 to $(N)-1, where $(N) is a macro supplied to the dbLoadRecords() command that loads the database. The "VALA" field contains double values from M to M+$(N)-1, where M is supplied at run time to the field "$(P)arrayTest_start".

CalcRecord.adl
CalcRecord_full.adl

The calc record, in EPICS base, does not come with display files. But, frequently, one would like to be able to display and interact with a calc record embedded in a database. The files serve that purpose.

calcExamples.adl
calcAlgebraicExamples.adl
calcArrayExamples.adl
calcBitwiseExamples.adl
calcMiscExamples.adl
calcRelationalExamples.adl
calcStringExamples.adl
calcTrigExamples.adl

These files document the expressions evaluated by calc, calcout, sCalcout, and aCalcout records.

calcout_settings.req

The calcout record, in EPICS base, does not come with an autosave-request file.

yyCalcoutRecord.adl
yyCalcoutRecord_full.adl

The calcout record, in EPICS base, does not come with display files. But, frequently, one would like to be able to display and interact with a calcout record embedded in a database. The files serve that purpose.

interp.db
interp_settings.req
interp.adl

This database implements array interpolation, and hosts three arrays: an independent variable array, X, whose PV name is "$(P)interp.VALA"); and two dependent variable arrays, Y1(X) and Y2(X), whose PV names are, respectively, "$(P)interp.VALB", and "$(P)interp.VALC".

The arrays can be loaded at boot time, using autosave; written to at run time by a CA client; or built up element by element at run time, by setting the MODE switch ("$(P)interp_mode") to "Add Entry".

To interpolate, one sets the mode switch to "Interpolate", and writes a number to the X-input field, "$(P)interp_x". This causes an underlying aSub record to interpolate the Yi arrays to find values that would correspond with that value of X, to display them as "$(P)interp_y1" and "$(P)interp_y2", and, optionally, to write them to the external PVs named in the link fields "$(P)interp_y1.OUT", and "$(P)interp_y2.OUT".

The interpolation performed is a Lagrange interpolation, where the degree of the polynomial can be specified by writing to "$(P)interp.F". The order must be in the range 1..10. Currently the database doesn't visibly enforce these limits, but silently clips to them if they are violated.

To add an element to the arrays, one sets the mode switch to "Add Element", writes Yi values to "$(P)interp_y1" and "$(P)interp_y2", and then writes the corresponding X value to "$(P)interp_x". The number of entries, "$(P)interp_n" will then increase by one.

The arrays can be cleared by setting the mode switch to "Clear All" and writing anything to X.

For more information, see interp.README.

userAve10.db
userAve10_settings.req
userAve.adl
userAve10.adl

These files implement, manage, and display a set of 10 sub records programmed (thanks to Frank Lenkszus) to calculate the average of M values, where M is given by "$(P)userAve$(N).A", which are read via the input link "$(P)userAve$(N).INPB". These records are intended for use in run-time programming. The records can operate in two ways:

Running average ("$(P)userAve$(N)_mode" == "CONTINUOUS")

After M values have been recorded, output the average of the most recent M value whenever a new value is read.

One-shot average ("$(P)userAve$(N)_mode" == "ONE-SHOT")

Clear the output, read M values, output the average of those values, and ignore new values until a restart command is received ("$(P)userAve$(N).C is set to 1).

In either mode, the record uses its alarm field to indicate whether the output value it is displaying ("$(P)userAve$(N).VAL") is valid (i.e., is the result of M readings). Until M readings have been read, the record will be in alarm (STAT=="SOFT", SEVR=="MAJOR"). After M readings have been averaged, STAT=="NO_ALARM", SEVR=="NO_ALARM".

userCalcN.db
userCalcN_noDisable.db
userCalcs10.db
userCalcN_settings.req
userCalcs10_settings.req
swait_settings.req
userCalc.adl
userCalcMeter.adl
userCalc_full.adl
userCalc_help.adl
userCalcs10.adl
userCalcs20.adl

A userCalc is simply a swait record implemented for use in run-time programming. "Implemented" means that a database containing several uncommitted swait records, with an overall enable switch, is loaded; corresponding entries are made in autosave files to save and restore selected field values; and reasonably comprehensive MEDM displays are provided so that a user can exercise most of the records' features.

Although the swait record is not recommended for new development, it is retained in this case because many users have become accustomed to the way it behaves -- in particular, to the way its links are programmed: they take only a PV name, without the link attributes (e.g., NPP, NMS) that standard EPICS links have.

userCalcOuts10.db
userCalcOuts10_settings.req
userCalcOut.adl
userCalcOut_full.adl
userCalcOuts10.adl

Just like a userCalc, but based on the calcout record, instead of the swait record.

userArrayCalcs10.db
userArrayCalcs10_settings.req
acalcout_settings.req
userArrayCalc.adl
userArrayCalcPlot.adl
userArrayCalcPlots10.adl
userArrayCalc_full.adl
userArrayCalc_plot.adl
userArrayCalcs10.adl
arrayPlot8.adl

Just like a userCalc, but based on the aCalcout (array calcout) record, instead of the swait record.

userStringCalcs10.db
userStringCalcs10_settings.req
scalcout_settings.req
userStringCalc.adl
userStringCalc_demo.adl
userStringCalc_full.adl
userStringCalcs10.adl

Just like a userCalc, but based on the aCalcout (array calcout) record, instead of the swait record.

yysCalcoutRecord.adl
yysCalcoutRecord_demo.adl
yysCalcoutRecord_full.adl

MEDM displays for a plain sCalcout record, i.e., one that is not also a userStringCalc.

userTransform.db
userTransforms10.db
userTransforms20.db
userTransforms10_settings.req
userTransforms20_settings.req
userTransform.adl
userTransform_full.adl
userTransforms10.adl
userTransforms20.adl

Just like a userCalc, but based on the transform record, instead of the swait record.

Transform.adl
Transform_full.adl
Transforms10.adl
transforms10.db
transforms10_settings.req
transform_settings.req

Just like a userTransform, but individually enabled/disabled.

yyTransform.adl
yyTransform_full.adl

MEDM displays for a plain transform record, i.e., one that is not also a userTransform.

waitRecN.db
yyWaitRecord.adl
yyWaitRecord_full.adl

MEDM displays for a plain swait record, i.e., one that is not also a userCalc, and a database to load a single swait record. These files are retained mostly for backward compatibility.

How to build and use

• Edit configure/RELEASE to specify the paths to EPICS base, and to the sscan module. If you don't have sscan, or don't want it to be used by the calc module, comment the definition out, and the calc module will adjust its build accordingly. The only thing calc can't build without sscan is the swait record, which is retained in calc mostly for historical reasons.

  The swait record is the original "userCalc" record, and many users at APS have become accustomed to the way it works. The calcout record from EPICS base, with "Async Soft Channel" device support, is a reasonable substitute for the swait record,

• Run Gnu Make to build.
• Note that the calc module is not useful on its own, but only produces code that can be used by other modules. (A good example of a module that uses the calc module is synApps' xxx module.) A module that uses calc should include calcSupport.dbd into the .dbd file it creates for loading into an ioc, or for export to other modules, and it should link to libcalc.