RRM 3-14 Preface

EPICS 3.14 Record Reference Manual

Preface

This is the 3.14 version of the EPICS Record Reference Manual. It replaces the format and organization of the previous versions. It was rewritten to make the EPICS database and its records easier to understand, and an introductory chapter, Chapter 1, explains basic database concepts, which will hopefully be very helpful to new EPICS users. In 3.14 version CapFast diagrams were replaced with VDCT equivalent. The remaining chapters all discuss each individual record, occasionally referring back to the introductory chapter when basic concepts are referred to, i.e., how monitors work, how database scanning works, etc.

Although this manual has attempted to be as thorough as possible, it is not yet complete. Hopefully, with more work and additions, it will be something the user can refer to in order to answer just about any question on any detail of any particular record.

Organization

This manual consists of an introductory chapter that explains basic database concepts, (Chapter 1), a chapter which explains fields common to all records, a third chapter which explains fields common to many records, and chapters which explain each individual record. The chapter on fields common to all records summarizes the characteristics of the fields which all records contain, though all records may not use all of them. The chapters on the individual records discuss the fields particular to each record. Of course, there is some overlap because some of the fields common to all record types function peculiarly within an individual record; however, this overlap has been kept to a minimum.

Conventions

There are many typeface and font variations intended to help the reader. The most important is the use of the Courier font to indicate literal strings, strings which should be entered as they appear in a field. For instance, some fields have a set menu of choices. When configuring the database, the choice which the user enters in the field must exactly match one of the menu choices (at least for those who are use VDCT as their database configuration tool). These choices appear in Courier font so that the reader can distinguish them from surrounding text. For instance, here is a passage from the analog output record explaining the OMSL field:

The first field that determines where the desired output originates is the output mode select field (OSML), which can have two possible values: closed_loop or supervisory. If supervisory is specified, the value in the VAL field can be set externally via dbPuts at run-time.

Here supervisory and closed_loop, the two possible choices in the OMSL fields, appear in Courier font and must be entered as is.

Record Tables

The chapter on the fields common to all record types, the chapter on the fields common to many record types, and the chapters on each record contain tables which present certain characteristics about each field. The format of these tables appears similar to the following which comes from the CPID record:

Field	Summary	Type	DCT	Initial	Access	Modify	Rec Proc Monitor	PP
OUT	Output Link	OUTLINK	Yes	0	No	No	N/A	No
ORBL	Output Readback Location	INLINK	Yes		No	No	No	No
more fields	...	...	...	...	...	...	...	...

The tables present the following information:

• The Field column contains the literal name of the particular field as it appears in the database.
• The Summary column contains the full name of the field.
• The Type column gives the EPICS type of the field. These types are defined in dbFldTypes.h
• The DCT column indicates whether the field is configurable prior to run-time.
• The Initial column contains the default initialization value of the field.
• The Access column indicates whether the field can be accessed by the database routines for reading purposes.
• The Modify column indicates whether the field can be changed at run-time, for example, by the operator.
• The Rec Proc Monitor column indicates whether or not the field is monitored at run-time for changes.
• The PP or process passive column indicates whether writing to this field over Channel Access will cause the record to process.

Inaccuracies

There are inaccuracies in the descriptions of the individual record types. Considering the number of record types and support modules now included in the EPICS release and the rate at which they are updated, it's certain that some of the information contained in the description of each of the records either is outdated or was never accurate. In either case, if an inaccuracy is noted, please bring to the attention of the author by sending a brief message describing where the inaccuracy is and what it is ([email protected]).

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EPICS Record Reference Manual - 19 MAY 1998