Array Analog Output (aao)

The array analog output record type is used to write array data. The array data can contain any of the supported data types. The record is in many ways similar to the waveform record but outputs arrays instead of reading them. It also allows the device support to allocate the array storage.

Parameter Fields

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

Scan Parameters

The array analog output record has the standard fields for specifying under what circumstances the record will 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

Write Parameters

These fields are configurable by the user to specify how and where to the record writes its data. The OUT field determines where the array analog output writes its output. It can be a hardware address, a channel access or database link, or a constant. Only in records that use soft device support can the OUT field be a channel access link, a database link, or a constant. Otherwise, the OUT field must be a hardware address. See Address Specification for information on the format of hardware addresses and database links.

Operator Display Parameters

These parameters are used to present meaningful data to the operator. They display the value and other parameters of the waveform either textually or graphically.

Alarm Parameters

The array analog output record has the alarm parameters common to all record types.

Monitor Parameters

These parameters are used to determine when to send monitors placed on the VAL field. The APST and MPST fields are a menu with choices “Always” and “On Change”. The default is “Always”, thus monitors will normally be sent every time the record processes. Selecting “On Change” causes a 32-bit hash of the VAL field buffer to be calculated and compared with the previous hash value every time the record processes; the monitor will only be sent if the hash is different, indicating that the buffer has changed. Note that there is a small chance that two different value buffers might result in the same hash value, so for critical systems “Always” may be a better choice, even though it re-sends duplicate data.

Run-time Parameters

These parameters are used by the run-time code for processing the array analog output record. They are not configured using a configuration tool. Only the VAL field is modifiable at run-time.

VAL references the array where the array analog output record stores its data. The BPTR field holds the address of the array.

The NORD field holds a counter of the number of elements that have been written to the output,

Field

Summary

Type

DCT

Default

Read

Write

CA PP

VAL

Value

DOUBLE[]

No

Yes

Yes

Yes

BPTR

Buffer Pointer

NOACCESS

No

No

No

No

NORD

Number elements read

ULONG

No

Yes

No

No

OMSL

Output Mode Select

MENU menuOmsl

Yes

Yes

Yes

No

DOL

Desired Output Link

INLINK

Yes

Yes

Yes

No

The following steps are performed in order during record processing.

Fetch Value

The OMSL menu field is used to determine whether the DOL link field should be used during processing or not:

  • If OMSL is supervisory the DOL field are not used. The new output value is taken from the VAL field, which may have been set from elsewhere.

  • If OMSL is closed_loop the DOL link field is read to obtain a value.

Note: The OMSL and DOL fields were added to the aaoRecord in Base 7.0.7.

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


Record Support

Record Support Routines

init_record

static long init_record(aaoRecord *prec, int pass)

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

Checks if device support allocated array space. If not, space for the array is allocated using NELM and FTVL. The array address is stored in the record.

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

This routine next checks to see that device support is available and a device support write routine is defined. If either does not exist, an error message is issued and processing is terminated

process

static long process(aaoRecord *prec)

See “Record Processing” section below.

cvt_dbaddr

static long cvt_dbaddr(DBADDR *paddr)

This is called by dbNameToAddr. It makes the dbAddr structure refer to the actual buffer holding the result.

get_array_info

static long get_array_info(DBADDR *paddr, long *no_elements, long *offset)

Obtains values from the array referenced by VAL.

put_array_info

static long put_array_info(DBADDR *paddr, long nNew)

Writes values into the array referenced by VAL.

get_units

static long get_units(DBADDR *paddr, char *units)

Retrieves EGU.

get_prec

static long get_precision(DBADDR *paddr, long *precision)

Retrieves PREC if field is VAL field. Otherwise, calls recGblGetPrec().

get_graphic_double

static long get_graphic_double(DBADDR *paddr, struct dbr_grDouble *pgd)

Sets the upper display and lower display limits for a field. If the field is VAL the limits are set to HOPR and LOPR, else if the field has upper and lower limits defined they will be used, else the upper and lower maximum values for the field type will be used.

Sets the following values:

upper_disp_limit = HOPR
lower_disp_limit = LOPR

get_control_double

static long get_control_double(DBADDR *paddr, struct dbr_ctrlDouble *pcd)

Sets the upper control and the lower control limits for a field. If the field is VAL the limits are set to HOPR and LOPR, else if the field has upper and lower limits defined they will be used, else the upper and lower maximum values for the field type will be used.

Sets the following values

upper_ctrl_limit = HOPR
lower_ctrl_limit = LOPR

Record Processing

Routine process implements the following algorithm:

  1. Check to see that the appropriate device support module exists. If it doesn’t, an error message is issued and processing is terminated with the PACT field still set to TRUE. This ensures that processes will no longer be called for this record. Thus error storms will not occur.

  2. Call device support write routine write_aao.

  3. If PACT has been changed to TRUE, the device support read routine has started but has not completed writing the new value. In this case, the processing routine merely returns, leaving PACT TRUE.

  4. Check to see if monitors should be invoked.

    • Alarm monitors are invoked if the alarm status or severity has changed.

    • Archive and value change monitors are invoked if APST or MPST are Always or if the result of the hash calculation is different.

    • NSEV and NSTA are reset to 0.

  5. Scan forward link if necessary, set PACT FALSE, and return.



Device Support

Fields Of Interest To Device Support

Each array analog output record record must have an associated set of device support routines. The primary responsibility of the device support routines is to write the array data value whenever write_aao() is called. 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

NSEV

New Alarm Severity

MENU menuAlarmSevr

No

Yes

No

No

NSTA

New Alarm Status

MENU menuAlarmStat

No

Yes

No

No

OUT

Output Specification

OUTLINK

Yes

Yes

Yes

No

NELM

Number of Elements

ULONG

Yes

1

Yes

No

No

FTVL

Field Type of Value

MENU menuFtype

Yes

Yes

No

No

BPTR

Buffer Pointer

NOACCESS

No

No

No

No

NORD

Number elements read

ULONG

No

Yes

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 no more than a small 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(dbCommon *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, dbCommon *precord, IOSCANPVT *ppvt)

This routine is called by the ioEventScan 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. It must be provided for any device type that can use the ioEvent scanner.

write_aao

long write_aao(dbCommon *precord)

This routine must write the array data to output. It returns the following values:

  • 0: Success.

  • Other: Error.

Device Support For Soft Records

The Soft Channel device support module is provided to write values to other records and store them in arrays. If OUT is a constant link, then write_aao() does nothing. In this case, the record can be used to hold arrays written via dbPuts. If OUT is a database or channel access link, the array value is written to the link. NORD is set to the number of items in the array.

If the OUT link type is constant, then NORD is set to zero.