Event Record (event)

The normal use for this record type is to post a soft-event and/or process a forward link. Soft Channel device support is provided to allow the soft-event name to be read from an input link. Hardware device support for this record can provide an interrupt handler routine to trigger processing of the record when an I/O Intr event occurs.

Parameter Fields

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

Scan Parameters

The event record has the standard fields for specifying under what circumstances it should be processed. These fields are described in Scan Fields.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
SCAN	Scan Mechanism	MENU menuScan	Yes		Yes	Yes	No
PHAS	Scan Phase	SHORT	Yes		Yes	Yes	No
EVNT	Event Name	STRING [40]	Yes		Yes	Yes	No
PRIO	Scheduling Priority	MENU menuPriority	Yes		Yes	Yes	No
PINI	Process at iocInit	MENU menuPini	Yes		Yes	Yes	No

Event Name Parameters

The VAL field is a string (prior to the Base-3.15.1 release it was a short integer) providing the name of an IOC soft-event. This named soft-event gets posted whenever the record is processed.

When the soft-event name is known at design time, the VAL field should be set to the name in a loaded database file. Soft-event names do not have to be registered before use, a handle for the name is automatically created and stored when a name is first seen and the same handle returned later if the same name is re-used.

The EPVT field holds the handle for the soft-event named in the VAL field. Looking up the handle for a soft-event name is fast and uses a hash table.

For records that use the default Soft Channel device support, the soft-event name can be fetched through the INP field link, written to the VAL field and the handle looked up during record processing.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
VAL	Event Name To Post	STRING [40]	Yes		Yes	Yes	No
EPVT	Event private	NOACCESS	No		No	No	No

Input Specification

The device support routines use the address in this record to obtain input. For records that provide an interrupt handler, the INP field should specify the address of the I/O card, and the DTYP field should specify a valid device support module.

The address format differs according to the card type used. See Address Specification for information on the format of hardware addresses and specifying links.

For soft records, the INP field can be a constant, a database link, or a channel access link, and the DTYP field should be empty or set to Soft Channel.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
INP	Input Specification	INLINK	Yes		Yes	Yes	No
DTYP	Device Type	DEVICE	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 Event record has the alarm parameters common to all record types. Alarm Fields lists other fields related to alarms that are common to all record types.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
STAT	Alarm Status	MENU menuAlarmStat	No	UDF	Yes	No	No
SEVR	Alarm Severity	MENU menuAlarmSevr	No		Yes	No	No
AMSG	Alarm Message	STRING [40]	No		Yes	No	No
NSTA	New Alarm Status	MENU menuAlarmStat	No		Yes	No	No
NSEV	New Alarm Severity	MENU menuAlarmSevr	No		Yes	No	No
NAMSG	New Alarm Message	STRING [40]	No		Yes	No	No
ACKS	Alarm Ack Severity	MENU menuAlarmSevr	No		Yes	No	No
ACKT	Alarm Ack Transient	MENU menuYesNo	Yes	YES	Yes	No	No
UDF	Undefined	UCHAR	Yes	1	Yes	Yes	Yes

Simulation Mode Parameters

The following fields are used to operate the event record in the simulation mode. See Fields Common to Input Record Types for more information on these fields.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
SIOL	Sim Input Specifctn	INLINK	Yes		Yes	Yes	No
SVAL	Simulation Value	STRING [40]	No		Yes	Yes	No
SIML	Sim Mode Location	INLINK	Yes		Yes	Yes	No
SIMM	Simulation Mode	MENU menuYesNo	No		Yes	Yes	No
SIMS	Sim mode Alarm Svrty	MENU menuAlarmSevr	Yes		Yes	Yes	No
SSCN	Sim. Mode Scan	MENU menuScan	Yes	65535	Yes	Yes	No
SDLY	Sim. Mode Async Delay	DOUBLE	Yes	-1.0	Yes	Yes	No

Record Support

Record Support Routines

init_record

This routine initializes SIMM with the value of SIML if SIML type is a CONSTANT link or creates a channel access link if SIML type is PV_LINK. SVAL is likewise initialized if SIOL is CONSTANT or PV_LINK.

If device support includes init_record(), it is called.

The string in VAL is converted to a soft-event handle in EPVT.

process

See next section.

special

When the VAL field is set, the new string is converted to a soft-event handle in EPVT.

Record Processing

Routine process() implements the following algorithm:

1. readValue() is called. See Input Records for more information.

2. If PACT has changed to TRUE, the device support read routine has started but has not completed reading a new soft-event name. In this case, the processing routine returns immediately, leaving PACT TRUE.

3. Set PACT to TRUE.

4. Post the soft-event whose handle is in EPVT.

5. Check to see if monitors should be invoked. Alarm monitors are invoked if the new alarm status or severity are non-zero.

6. Scan forward link if set, set PACT to FALSE, and return.

Device Support

Fields of Interest To Device Support

Each record must have an associated set of device support routines. The device support routines are primarily interested in the following fields:

Field	Summary	Type	DCT	Default	Read	Write	CA PP
PACT	Record active	UCHAR	No		Yes	No	No
DPVT	Device Private	NOACCESS	No		No	No	No
UDF	Undefined	UCHAR	Yes	1	Yes	Yes	Yes
NSEV	New Alarm Severity	MENU menuAlarmSevr	No		Yes	No	No
NSTA	New Alarm Status	MENU menuAlarmStat	No		Yes	No	No
INP	Input Specification	INLINK	Yes		Yes	Yes	No
PRIO	Scheduling Priority	MENU menuPriority	Yes		Yes	Yes	No
VAL	Event Name To Post	STRING [40]	Yes		Yes	Yes	No
EPVT	Event private	NOACCESS	No		No	No	No

Device Support Routines

Device support consists of the following routines:

report

long report(int level)

This optional routine is called by the IOC command dbior and is passed the report level that was requested by the user. It should print a report on the state of the device support to stdout. The level parameter may be used to output increasingly more detailed information at higher levels, or to select different types of information with different levels. Level zero should print only a 1-line summary.

init

long init(int after)

This optional routine is called twice at IOC initialization time. The first call happens before any of the init_record() calls are made, with the integer parameter after set to 0. The second call happens after all of the init_record() calls have been made, with after set to 1.

init_record

long init_record(precord)

This routine is optional. If provided, it is called by the record support init_record() routine.

get_ioint_info

long get_ioint_info(int cmd, struct dbCommon *precord, IOSCANPVT *ppvt)

This routine is called by the dbScan system each time the record is added or deleted from an I/O event scan list. cmd has the value (0, 1) if the record is being (added to, deleted from) an I/O event list. The get_ioint_info routine is optional, but must be provided by any device support that implements I/O Intr scanning for the event record type.

read_event

long read_event(precord)

This routine returns the following values:

• 0: Success.

• Other: Error.

Device Support For Soft Records

A Soft Channel device support module is available. The INP link field is used to fetch the soft-event name.

The read_event() routine reads a string through INP and stores it in VAL, then looks up the named soft-event handle and sets EPVT.

See Input Records for details on soft input.