Long String Output Record (lso)

The long string output record is used to write an arbitrary ASCII string with a maximum length of 65535 characters.

Parameter Fields

The record-specific fields are described below, grouped by functionality.

Scan Parameters

The long string output record has the standard fields for specifying under what circumstances it will be processed. These fields are listed in Scan Fields.

Desired Output Parameters

The long string output record must specify from where it gets its desired output string. The first field that determines where the desired output originates is the output mode select (OMSL) field, which can have two possible values: closed_loop or supervisory. If closed_loop is specified, the VAL field’s value is fetched from the address specified in the Desired Output Link field (DOL) which can be either a database link or a channel access link. If supervisory is specified, DOL is ignored, the current value of VAL is written, and VAL can be changed externally via dbPuts at run-time.

The maximum number of characters in VAL is given by SIZV, and cannot be larger than 65535.

DOL can also be a constant instead of a link, in which case VAL is initialized to the constant value. Most simple string constants are likely to be interpreted as a CA link name though. To initialize a string output record it is simplest to set the VAL field directly; alternatively use a JSON constant link type in the DOL field.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
VAL	Current Value	STRING or CHAR[SIZV]	No		Yes	Yes	Yes
SIZV	Size of buffers	USHORT	Yes	41	Yes	No	No
DOL	Desired Output Link	INLINK	Yes		Yes	Yes	No
OMSL	Output Mode Select	MENU menuOmsl	Yes		Yes	Yes	No

Output Specification

The output link specified in the OUT field specifies where the long string output record is to write its string. The link can be a database or channel access link. If the OUT field is a constant, no output will be written.

In addition, the appropriate device support module must be entered into the DTYP field.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
OUT	Output Specification	OUTLINK	Yes		Yes	Yes	No
DTYP	Device Type	DEVICE	Yes		Yes	Yes	No

Monitor Parameters

These parameters are used to specify when the monitor post should be sent by the monitor() routine. There are two possible choices:

APST is used for archiver monitors and MPST for all other type of monitors.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
MPST	Post Value Monitors	MENU menuPost	Yes		Yes	Yes	No
APST	Post Archive Monitors	MENU menuPost	Yes		Yes	Yes	No

Operator Display Parameters

See Fields Common to All Record Types for more on the record name (NAME) and description (DESC) fields.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
NAME	Record Name	STRING [61]	No		Yes	No	No
DESC	Descriptor	STRING [41]	Yes		Yes	Yes	No

Alarm Parameters

The long string input record has the same alarm parameters common to all record types. Alarm Fields lists the fields related to alarms that are common to all record types.

The IVOA field specifies an action to take when the INVALID alarm is triggered. When Set output to IVOV, the value contained in the IVOV field is written to the output link during an alarm condition. See Invalid Output Action Fields for more information on the IVOA and IVOV fields.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
IVOA	INVALID Output Action	MENU menuIvoa	Yes		Yes	Yes	No
IVOV	INVALID Output Value	STRING [40]	Yes		Yes	Yes	No

Run-time Parameters

The old value field (OVAL) of the long string input record is used to implement value change monitors for VAL. If VAL is not equal to OVAL, then monitors are triggered. LEN contains the length of the string in VAL, OLEN contains the length of the string in OVAL.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
OVAL	Previous Value	STRING or [SIZV]	No		Yes	No	No
LEN	Length of VAL	ULONG	No		Yes	No	No
OLEN	Length of OVAL	ULONG	No		Yes	No	No

Simulation Mode Parameters

The following fields are used to operate the record in simulation mode.

If SIMM (fetched through SIML) is YES, the record is put in SIMS severity and the value is written through SIOL. SSCN sets a different SCAN mechanism to use in simulation mode. SDLY sets a delay (in sec) that is used for asynchronous simulation processing.

See Output Simulation Fields for more information on simulation mode and its fields.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
SIML	Simulation Mode link	INLINK	Yes		Yes	Yes	No
SIMM	Simulation Mode	MENU menuYesNo	No		Yes	Yes	No
SIOL	Simulation Output Link	OUTLINK	Yes		Yes	Yes	No
SIMS	Simulation Mode Severity	MENU menuAlarmSevr	Yes		Yes	Yes	No
SDLY	Sim. Mode Async Delay	DOUBLE	Yes	-1.0	Yes	Yes	No
SSCN	Sim. Mode Scan	MENU menuScan	Yes	65535	Yes	Yes	No

Device Support Interface

The record defines a device support entry table type lsodset in the generated lsoRecord.h file as follows:

typedef struct lsodset {
    dset common;
    long (*write_string)(struct lsoRecord *prec);
} lsodset;
#define HAS_lsodset

The support module must set common.number to at least 5, and provide a pointer to its write_string() routine; the other function pointers may be NULL if their associated functionality is not required for this support layer. Most device supports also provide a common.init_record() routine to configure the record instance and connect it to the hardware or driver support layer.

Device Support for Soft Records

Device support for DTYP Soft Channel is provided for writing values to other records or other software components.

Device support for DTYP stdio is provided for writing values to the stdout, stderr, or errlog streams. INST_IO addressing @stdout, @stderr or @errlog is used on the OUT link field to select the desired stream.