Array Subroutine Record (aSub)

The aSub record is an advanced variant of the ‘sub’ (subroutine) record which has a number of additional features:

• It provides 20 different input and output fields which can hold array or scalar values. The types and array capacities of these are user configurable, and they all have an associated input or output link.

• The name of the C or C++ subroutine to be called when the record processes can be changed dynamically while the IOC is running. The name can either be fetched from another record using an input link, or written directly into the SNAM field.

• The user can choose whether monitor events should be posted for the output fields.

• The VAL field is set to the return value from the user subroutine, which is treated as a status value and controls whether the output links will be used or not. The record can also raise an alarm with a chosen severity if the status value is non-zero.

Record-specific Menus

Menu aSubLFLG

The LFLG menu field controls whether the SUBL link will be read to update the name of the subroutine to be called when the record processes.

Index	Identifier	Choice String
0	aSubLFLG_IGNORE	IGNORE
1	aSubLFLG_READ	READ

Menu aSubEFLG

The EFLG menu field indicates whether monitor events should be posted for the VALA..VALU output value fields.

Index	Identifier	Choice String
0	aSubEFLG_NEVER	NEVER
1	aSubEFLG_ON_CHANGE	ON CHANGE
2	aSubEFLG_ALWAYS	ALWAYS

Parameter Fields

The record-specific fields are described below.

Subroutine Fields

The VAL field is set to the value returned by the user subroutine. The value is treated as an error status value where zero mean success. The output links OUTA … OUTU will only be used to forward the associated output value fields when the subroutine has returned a zero status. If the return status was less than zero, the record will be put into SOFT_ALARM state with severity given by the BRSV field.

The INAM field may be used to name a subroutine that will be called once at IOC initialization time.

LFLG tells the record whether to read or ignore the SUBL link. If the value is READ, then the name of the subroutine to be called at process time is read from SUBL. If the value is IGNORE, the name of the subroutine is that currently held in SNAM.

A string is read from the SUBL link to fetch the name of the subroutine to be run during record processing.

SNAM holds the name of the subroutine to be called when the record processes. The value in this field can be overwritten by the SUBL link if LFLG is set to READ.

The SADR field is only accessible from C code; it points to the subroutine to be called.

The CADR field may be set by the user subroutine to point to another function that will be called immediately before setting the SADR field to some other routine. This allows the main user subroutine to allocate resources when it is first called and be able to release them again when they are no longer needed.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
VAL	Subr. return value	LONG	No		Yes	Yes	No
OVAL	Old return value	LONG	No		Yes	No	No
INAM	Initialize Subr. Name	STRING [41]	Yes		Yes	No	No
LFLG	Subr. Input Enable	MENU aSubLFLG	Yes		Yes	Yes	No
SUBL	Subroutine Name Link	INLINK	Yes		Yes	No	No
SNAM	Process Subr. Name	STRING [41]	Yes		Yes	Yes	No
ONAM	Old Subr. Name	STRING [41]	Yes		Yes	No	No
SADR	Subroutine Address	NOACCESS	No		No	No	No
CADR	Subroutine Cleanup Address	NOACCESS	No		No	No	No
BRSV	Bad Return Severity	MENU menuAlarmSevr	Yes		Yes	Yes	Yes

Operator Display Parameters

The PREC field specifies the number of decimal places with which to display the values of the value fields A … U and VALA … VALU. Except when it doesn’t.

Output Event Flag

This field tells the record when to post change events on the output fields VALA … VALU. If the value is NEVER, events are never posted. If the value is ALWAYS, events are posted every time the record processes. If the value is ON CHANGE, events are posted when any element of an array changes value. This flag controls value, log (archive) and alarm change events.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
EFLG	Output Event Flag	MENU aSubEFLG	Yes	1	Yes	Yes	No

Input Link Fields

The input links from where the values of A,…,U are fetched during record processing.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
INPA	Input Link A	INLINK	Yes		Yes	Yes	No
INPB	Input Link B	INLINK	Yes		Yes	Yes	No
INPC	Input Link C	INLINK	Yes		Yes	Yes	No
INPD	Input Link D	INLINK	Yes		Yes	Yes	No
INPE	Input Link E	INLINK	Yes		Yes	Yes	No
INPF	Input Link F	INLINK	Yes		Yes	Yes	No
INPG	Input Link G	INLINK	Yes		Yes	Yes	No
INPH	Input Link H	INLINK	Yes		Yes	Yes	No
INPI	Input Link I	INLINK	Yes		Yes	Yes	No
INPJ	Input Link J	INLINK	Yes		Yes	Yes	No
INPK	Input Link K	INLINK	Yes		Yes	Yes	No
INPL	Input Link L	INLINK	Yes		Yes	Yes	No
INPM	Input Link M	INLINK	Yes		Yes	Yes	No
INPN	Input Link N	INLINK	Yes		Yes	Yes	No
INPO	Input Link O	INLINK	Yes		Yes	Yes	No
INPP	Input Link P	INLINK	Yes		Yes	Yes	No
INPQ	Input Link Q	INLINK	Yes		Yes	Yes	No
INPR	Input Link R	INLINK	Yes		Yes	Yes	No
INPS	Input Link S	INLINK	Yes		Yes	Yes	No
INPT	Input Link T	INLINK	Yes		Yes	Yes	No
INPU	Input Link U	INLINK	Yes		Yes	Yes	No

Input Value Fields

Thse fields hold the scalar or array values fetched through the input links INPA,…,INPU.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
A	Input value A	Set by FTA	No		Yes	Yes	No
B	Input value B	Set by FTB	No		Yes	Yes	No
C	Input value C	Set by FTC	No		Yes	Yes	No
D	Input value D	Set by FTD	No		Yes	Yes	No
E	Input value E	Set by FTE	No		Yes	Yes	No
F	Input value F	Set by FTF	No		Yes	Yes	No
G	Input value G	Set by FTG	No		Yes	Yes	No
H	Input value H	Set by FTH	No		Yes	Yes	No
I	Input value I	Set by FTI	No		Yes	Yes	No
J	Input value J	Set by FTJ	No		Yes	Yes	No
K	Input value K	Set by FTK	No		Yes	Yes	No
L	Input value L	Set by FTL	No		Yes	Yes	No
M	Input value M	Set by FTM	No		Yes	Yes	No
N	Input value N	Set by FTN	No		Yes	Yes	No
O	Input value O	Set by FTO	No		Yes	Yes	No
P	Input value P	Set by FTP	No		Yes	Yes	No
Q	Input value Q	Set by FTQ	No		Yes	Yes	No
R	Input value R	Set by FTR	No		Yes	Yes	No
S	Input value S	Set by FTS	No		Yes	Yes	No
T	Input value T	Set by FTT	No		Yes	Yes	No
U	Input value U	Set by FTU	No		Yes	Yes	No

Input Value Data Types

Field types of the input value fields. The choices can be found by following the link to the menuFtype definition.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
FTA	Type of A	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTB	Type of B	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTC	Type of C	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTD	Type of D	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTE	Type of E	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTF	Type of F	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTG	Type of G	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTH	Type of H	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTI	Type of I	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTJ	Type of J	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTK	Type of K	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTL	Type of L	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTM	Type of M	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTN	Type of N	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTO	Type of O	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTP	Type of P	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTQ	Type of Q	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTR	Type of R	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTS	Type of S	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTT	Type of T	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTU	Type of U	MENU menuFtype	Yes	DOUBLE	Yes	No	No

Input Value Array Capacity

These fields specify how many array elements the input value fields may hold.

Note that access to the NOT field from C code must use the field name in upper case, e.g. prec->NOT since the lower-case not is a reserved word in C++ and cannot be used as an identifier.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
NOA	Max. elements in A	ULONG	Yes	1	Yes	No	No
NOB	Max. elements in B	ULONG	Yes	1	Yes	No	No
NOC	Max. elements in C	ULONG	Yes	1	Yes	No	No
NOD	Max. elements in D	ULONG	Yes	1	Yes	No	No
NOE	Max. elements in E	ULONG	Yes	1	Yes	No	No
NOF	Max. elements in F	ULONG	Yes	1	Yes	No	No
NOG	Max. elements in G	ULONG	Yes	1	Yes	No	No
NOH	Max. elements in H	ULONG	Yes	1	Yes	No	No
NOI	Max. elements in I	ULONG	Yes	1	Yes	No	No
NOJ	Max. elements in J	ULONG	Yes	1	Yes	No	No
NOK	Max. elements in K	ULONG	Yes	1	Yes	No	No
NOL	Max. elements in L	ULONG	Yes	1	Yes	No	No
NOM	Max. elements in M	ULONG	Yes	1	Yes	No	No
NON	Max. elements in N	ULONG	Yes	1	Yes	No	No
NOO	Max. elements in O	ULONG	Yes	1	Yes	No	No
NOP	Max. elements in P	ULONG	Yes	1	Yes	No	No
NOQ	Max. elements in Q	ULONG	Yes	1	Yes	No	No
NOR	Max. elements in R	ULONG	Yes	1	Yes	No	No
NOS	Max. elements in S	ULONG	Yes	1	Yes	No	No
NOT	Max. elements in T	ULONG	Yes	1	Yes	No	No
NOU	Max. elements in U	ULONG	Yes	1	Yes	No	No

Input Value Array Size

These fields specify how many array elements the input value fields currently contain.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
NEA	Num. elements in A	ULONG	No	1	Yes	No	No
NEB	Num. elements in B	ULONG	No	1	Yes	No	No
NEC	Num. elements in C	ULONG	No	1	Yes	No	No
NED	Num. elements in D	ULONG	No	1	Yes	No	No
NEE	Num. elements in E	ULONG	No	1	Yes	No	No
NEF	Num. elements in F	ULONG	No	1	Yes	No	No
NEG	Num. elements in G	ULONG	No	1	Yes	No	No
NEH	Num. elements in H	ULONG	No	1	Yes	No	No
NEI	Num. elements in I	ULONG	No	1	Yes	No	No
NEJ	Num. elements in J	ULONG	No	1	Yes	No	No
NEK	Num. elements in K	ULONG	No	1	Yes	No	No
NEL	Num. elements in L	ULONG	No	1	Yes	No	No
NEM	Num. elements in M	ULONG	No	1	Yes	No	No
NEN	Num. elements in N	ULONG	No	1	Yes	No	No
NEO	Num. elements in O	ULONG	No	1	Yes	No	No
NEP	Num. elements in P	ULONG	No	1	Yes	No	No
NEQ	Num. elements in Q	ULONG	No	1	Yes	No	No
NER	Num. elements in R	ULONG	No	1	Yes	No	No
NES	Num. elements in S	ULONG	No	1	Yes	No	No
NET	Num. elements in T	ULONG	No	1	Yes	No	No
NEU	Num. elements in U	ULONG	No	1	Yes	No	No

Output Link Fields

The output links through which the VALA … VALU field values are sent during record processing, provided the subroutine returned 0.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
OUTA	Output Link A	OUTLINK	Yes		Yes	Yes	No
OUTB	Output Link B	OUTLINK	Yes		Yes	Yes	No
OUTC	Output Link C	OUTLINK	Yes		Yes	Yes	No
OUTD	Output Link D	OUTLINK	Yes		Yes	Yes	No
OUTE	Output Link E	OUTLINK	Yes		Yes	Yes	No
OUTF	Output Link F	OUTLINK	Yes		Yes	Yes	No
OUTG	Output Link G	OUTLINK	Yes		Yes	Yes	No
OUTH	Output Link H	OUTLINK	Yes		Yes	Yes	No
OUTI	Output Link I	OUTLINK	Yes		Yes	Yes	No
OUTJ	Output Link J	OUTLINK	Yes		Yes	Yes	No
OUTK	Output Link K	OUTLINK	Yes		Yes	Yes	No
OUTL	Output Link L	OUTLINK	Yes		Yes	Yes	No
OUTM	Output Link M	OUTLINK	Yes		Yes	Yes	No
OUTN	Output Link N	OUTLINK	Yes		Yes	Yes	No
OUTO	Output Link O	OUTLINK	Yes		Yes	Yes	No
OUTP	Output Link P	OUTLINK	Yes		Yes	Yes	No
OUTQ	Output Link Q	OUTLINK	Yes		Yes	Yes	No
OUTR	Output Link R	OUTLINK	Yes		Yes	Yes	No
OUTS	Output Link S	OUTLINK	Yes		Yes	Yes	No
OUTT	Output Link T	OUTLINK	Yes		Yes	Yes	No
OUTU	Output Link U	OUTLINK	Yes		Yes	Yes	No

Output Value Fields

These fields hold scalar or array data generated by the subroutine which will be sent through the OUTA … OUTU links during record processing.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
VALA	Output value A	Set by FTVA	No		Yes	Yes	No
VALB	Output value B	Set by FTVB	No		Yes	Yes	No
VALC	Output value C	Set by FTVC	No		Yes	Yes	No
VALD	Output value D	Set by FTVD	No		Yes	Yes	No
VALE	Output value E	Set by FTVE	No		Yes	Yes	No
VALF	Output value F	Set by FTVF	No		Yes	Yes	No
VALG	Output value G	Set by FTVG	No		Yes	Yes	No
VALH	Output value H	Set by FTVH	No		Yes	Yes	No
VALI	Output value I	Set by FTVI	No		Yes	Yes	No
VALJ	Output value J	Set by FTVJ	No		Yes	Yes	No
VALK	Output value K	Set by FTVK	No		Yes	Yes	No
VALL	Output value L	Set by FTVL	No		Yes	Yes	No
VALM	Output value M	Set by FTVM	No		Yes	Yes	No
VALN	Output value N	Set by FTVN	No		Yes	Yes	No
VALO	Output value O	Set by FTVO	No		Yes	Yes	No
VALP	Output value P	Set by FTVP	No		Yes	Yes	No
VALQ	Output value Q	Set by FTVQ	No		Yes	Yes	No
VALR	Output value R	Set by FTVR	No		Yes	Yes	No
VALS	Output value S	Set by FTVS	No		Yes	Yes	No
VALT	Output value T	Set by FTVT	No		Yes	Yes	No
VALU	Output value U	Set by FTVU	No		Yes	Yes	No

Old Value Fields

The previous values of the output fields. These are used to determine when to post events if EFLG is set to ON CHANGE.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
OVLA	Old Output A	NOACCESS	No		No	No	No
OVLB	Old Output B	NOACCESS	No		No	No	No
OVLC	Old Output C	NOACCESS	No		No	No	No
OVLD	Old Output D	NOACCESS	No		No	No	No
OVLE	Old Output E	NOACCESS	No		No	No	No
OVLF	Old Output F	NOACCESS	No		No	No	No
OVLG	Old Output G	NOACCESS	No		No	No	No
OVLH	Old Output H	NOACCESS	No		No	No	No
OVLI	Old Output I	NOACCESS	No		No	No	No
OVLJ	Old Output J	NOACCESS	No		No	No	No
OVLK	Old Output K	NOACCESS	No		No	No	No
OVLL	Old Output L	NOACCESS	No		No	No	No
OVLM	Old Output M	NOACCESS	No		No	No	No
OVLN	Old Output N	NOACCESS	No		No	No	No
OVLO	Old Output O	NOACCESS	No		No	No	No
OVLP	Old Output P	NOACCESS	No		No	No	No
OVLQ	Old Output Q	NOACCESS	No		No	No	No
OVLR	Old Output R	NOACCESS	No		No	No	No
OVLS	Old Output S	NOACCESS	No		No	No	No
OVLT	Old Output T	NOACCESS	No		No	No	No
OVLU	Old Output U	NOACCESS	No		No	No	No

Output Value Data Types

Field types of the output value fields. The choices can be found by following a link to the menuFtype definition.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
FTVA	Type of VALA	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVB	Type of VALB	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVC	Type of VALC	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVD	Type of VALD	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVE	Type of VALE	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVF	Type of VALF	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVG	Type of VALG	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVH	Type of VALH	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVI	Type of VALI	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVJ	Type of VALJ	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVK	Type of VALK	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVL	Type of VALL	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVM	Type of VALM	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVN	Type of VALN	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVO	Type of VALO	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVP	Type of VALP	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVQ	Type of VALQ	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVR	Type of VALR	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVS	Type of VALS	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVT	Type of VALT	MENU menuFtype	Yes	DOUBLE	Yes	No	No
FTVU	Type of VALU	MENU menuFtype	Yes	DOUBLE	Yes	No	No

Output Value Array Capacity

These fields specify how many array elements the output value fields may hold.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
NOVA	Max. elements in VALA	ULONG	Yes	1	Yes	No	No
NOVB	Max. elements in VALB	ULONG	Yes	1	Yes	No	No
NOVC	Max. elements in VALC	ULONG	Yes	1	Yes	No	No
NOVD	Max. elements in VALD	ULONG	Yes	1	Yes	No	No
NOVE	Max. elements in VALE	ULONG	Yes	1	Yes	No	No
NOVF	Max. elements in VALF	ULONG	Yes	1	Yes	No	No
NOVG	Max. elements in VALG	ULONG	Yes	1	Yes	No	No
NOVH	Max. elements in VAlH	ULONG	Yes	1	Yes	No	No
NOVI	Max. elements in VALI	ULONG	Yes	1	Yes	No	No
NOVJ	Max. elements in VALJ	ULONG	Yes	1	Yes	No	No
NOVK	Max. elements in VALK	ULONG	Yes	1	Yes	No	No
NOVL	Max. elements in VALL	ULONG	Yes	1	Yes	No	No
NOVM	Max. elements in VALM	ULONG	Yes	1	Yes	No	No
NOVN	Max. elements in VALN	ULONG	Yes	1	Yes	No	No
NOVO	Max. elements in VALO	ULONG	Yes	1	Yes	No	No
NOVP	Max. elements in VALP	ULONG	Yes	1	Yes	No	No
NOVQ	Max. elements in VALQ	ULONG	Yes	1	Yes	No	No
NOVR	Max. elements in VALR	ULONG	Yes	1	Yes	No	No
NOVS	Max. elements in VALS	ULONG	Yes	1	Yes	No	No
NOVT	Max. elements in VALT	ULONG	Yes	1	Yes	No	No
NOVU	Max. elements in VALU	ULONG	Yes	1	Yes	No	No

Output Value Array Size

These fields specify how many array elements the output value fields currently contain.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
NEVA	Num. elements in VALA	ULONG	No	1	Yes	No	No
NEVB	Num. elements in VALB	ULONG	No	1	Yes	No	No
NEVC	Num. elements in VALC	ULONG	No	1	Yes	No	No
NEVD	Num. elements in VALD	ULONG	No	1	Yes	No	No
NEVE	Num. elements in VALE	ULONG	No	1	Yes	No	No
NEVF	Num. elements in VALF	ULONG	No	1	Yes	No	No
NEVG	Num. elements in VALG	ULONG	No	1	Yes	No	No
NEVH	Num. elements in VAlH	ULONG	No	1	Yes	No	No
NEVI	Num. elements in VALI	ULONG	No	1	Yes	No	No
NEVJ	Num. elements in VALJ	ULONG	No	1	Yes	No	No
NEVK	Num. elements in VALK	ULONG	No	1	Yes	No	No
NEVL	Num. elements in VALL	ULONG	No	1	Yes	No	No
NEVM	Num. elements in VALM	ULONG	No	1	Yes	No	No
NEVN	Num. elements in VALN	ULONG	No	1	Yes	No	No
NEVO	Num. elements in VALO	ULONG	No	1	Yes	No	No
NEVP	Num. elements in VALP	ULONG	No	1	Yes	No	No
NEVQ	Num. elements in VALQ	ULONG	No	1	Yes	No	No
NEVR	Num. elements in VALR	ULONG	No	1	Yes	No	No
NEVS	Num. elements in VALS	ULONG	No	1	Yes	No	No
NEVT	Num. elements in VALT	ULONG	No	1	Yes	No	No
NEVU	Num. elements in VALU	ULONG	No	1	Yes	No	No

Old Value Array Size

These fields specify how many array elements the old value fields currently contain.

Field	Summary	Type	DCT	Default	Read	Write	CA PP
ONVA	Num. elements in OVLA	ULONG	No	1	Yes	No	No
ONVB	Num. elements in OVLB	ULONG	No	1	Yes	No	No
ONVC	Num. elements in OVLC	ULONG	No	1	Yes	No	No
ONVD	Num. elements in OVLD	ULONG	No	1	Yes	No	No
ONVE	Num. elements in OVLE	ULONG	No	1	Yes	No	No
ONVF	Num. elements in OVLF	ULONG	No	1	Yes	No	No
ONVG	Num. elements in OVLG	ULONG	No	1	Yes	No	No
ONVH	Num. elements in VAlH	ULONG	No	1	Yes	No	No
ONVI	Num. elements in OVLI	ULONG	No	1	Yes	No	No
ONVJ	Num. elements in OVLJ	ULONG	No	1	Yes	No	No
ONVK	Num. elements in OVLK	ULONG	No	1	Yes	No	No
ONVL	Num. elements in OVLL	ULONG	No	1	Yes	No	No
ONVM	Num. elements in OVLM	ULONG	No	1	Yes	No	No
ONVN	Num. elements in OVLN	ULONG	No	1	Yes	No	No
ONVO	Num. elements in OVLO	ULONG	No	1	Yes	No	No
ONVP	Num. elements in OVLP	ULONG	No	1	Yes	No	No
ONVQ	Num. elements in OVLQ	ULONG	No	1	Yes	No	No
ONVR	Num. elements in OVLR	ULONG	No	1	Yes	No	No
ONVS	Num. elements in OVLS	ULONG	No	1	Yes	No	No
ONVT	Num. elements in OVLT	ULONG	No	1	Yes	No	No
ONVU	Num. elements in OVLU	ULONG	No	1	Yes	No	No

---

Record Support Routines

init_record

long (*init_record)(struct dbCommon *precord, int pass)

This routine is called twice at iocInit. On the first call it does the following:

• Calloc sufficient space to hold the number of input scalars and/or arrays defined by the settings of the fields FTA-FTU and NOA-NOU. Initialize fields NE* to the values of the associated NO* field values.

• Calloc sufficient space to hold the number of output scalars and/or arrays defined by the settings of the fields FTVA-FTVU and NOVA-NOVU. For the output fields, also calloc space to hold the previous value of a field. This is required when the decision is made on whether or not to post events.

On the second call, it does the following:

• Initializes SUBL if it is a constant link.

• Initializes each constant input link.

• If the field INAM is set, look-up the address of the routine and call it.

• If the field LFLG is set to IGNORE and SNAM is defined, look up the address of the process routine.

process

long (*process)(struct dbCommon *precord)

This routine implements the following algorithm:

• If PACT is FALSE, perform normal processing

• If PACT is TRUE, perform asynchronous-completion processing

Normal processing:

• Set PACT to TRUE.

• If the field LFLG is set to READ, get the subroutine name from the SUBL link. If the name is not NULL and it is not the same as the previous subroutine name, look up the subroutine address. Set the old subroutine name, ONAM, equal to the current name, SNAM.

• Fetch the values from the input links.

• Set PACT to FALSE

• If all input-link fetches succeeded, call the routine specified by SNAM.

• Set VAL equal to the return value from the routine specified by SNAM.

• If the SNAM routine set PACT to TRUE, then return. In this case, we presume the routine has arranged that process will be called at some later time for asynchronous completion.

• Set PACT to TRUE.

• If VAL is zero, write the output values using the output links.

• Get the time of processing and put it into the timestamp field.

• If VAL has changed, post a change-of value and log event for this field. If EFLG is set to ALWAYS, post change-of-value and log events for every output field. If EFLG is set to ON CHANGE, post change-of-value and log events for every output field which has changed. In the case of an array, an event will be posted if any single element of the array has changed. If EFLG is set to NEVER, no change-of-value or log events are posted for the output fields.

• Process the record on the end of the forward link, if one exists.

• Set PACT to FALSE.

Asynchronous-completion processing:

• Call the routine specified by SNAM (again).

• Set VAL equal to the return value from the routine specified by SNAM.

• Set PACT to TRUE.

• If VAL is zero, write the output values using the output links.

• Get the time of processing and put it into the timestamp field.

• If VAL has changed, post a change-of value and log event for this field. If EFLG is set to ALWAYS, post change-of-value and log events for every output field. If EFLG is set to ON CHANGE, post change-of-value and log events for every output field which has changed. In the case of an array, an event will be posted if any single element of the array has changed. If EFLG is set to NEVER, no change-of-value or log events are posted for the output fields.

• Process the record on the end of the forward link, if one exists.

• Set PACT to FALSE.

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Use of the aSub Record

The aSub record has input-value fields (A-U) and output-value fields (VALA-VALU), which are completely independent. The input-value fields have associated input links (INPA-INPU), and the output-value fields have associated output links (OUTA-OUTU). Both inputs and outputs have type fields (FTA-FTU, FTVA-FTVU, which default to ‘DOUBLE’) and number-of-element fields (NOA-NOU, NOVA-NOVU, which default to ‘1’). The output links OUTA-OUTU will only be processed if the subroutine returns a zero (OK) status value.

Example database fragment

To use the A field to read an array from some other record, then, you would need a database fragment that might look something like this:

record(aSub,"my_asub_record") {
    field(SNAM,"my_asub_routine")
    ...
    field(FTA, "LONG")
    field(NOA, "100")
    field(INPA, "myWaveform_1 NPP NMS")
    ...
}

If you wanted some other record to be able to write to the A field, then you would delete the input link above. If you wanted the A field to hold a scalar value, you would either delete the NOA specification, or specify it as “1”.

Example subroutine fragment

The associated subroutine code that uses the A field might look like this:

static long my_asub_routine(aSubRecord *prec) {
    long i, *a;
    double sum=0;
    ...
    a = (long *)prec->a;
    for (i=0; i<prec->noa; i++) {
        sum += a[i];
    }
    ...
    return 0; /* process output links */
}

Note that the subroutine code must always handle the value fields (A-U, VALA-VALU) as arrays, even if they contain only a single element.

Required export code

Aside from your own code, you must export and register your subroutines so the record can locate them. The simplest way is as follows:

#include <registryFunction.h>
#include <epicsExport.h>

static long my_asub_routine(aSubRecord *prec) {
    ...
}
epicsRegisterFunction(my_asub_routine);

Required database-definition code

The .dbd file loaded by the ioc must then contain the following line, which tells the linker to include your object file in the IOC binary:

function(my_asub_routine)

Device support, writing to hardware

The aSub record does not call any device support routines. If you want to write to hardware, you might use your output fields and links to write to some other record that can write to hardware.

Dynamically Changing the User Routine called during Record Processing

The aSub record allows the user to dynamically change which routine is called when the record processes. This can be done in two ways:

• The LFLG field can be set to READ so that the name of the routine is read from the SUBL link. Thus, whatever is feeding this link can change the name of the routine before the aSub record is processed. In this case, the record looks in the symbol table for the symbol name whenever the name of routine fetched from the link changes.

• The LFLG field can be set to IGNORE. In this case, the routine called during record processing is that specified in the SNAM field. Under these conditions, the SNAM field can be changed by a Channel Access write to that field. During development when trying several versions of the routine, it is not necessary to reboot the IOC and reload the database. A new routine can be loaded with the vxWorks ld command, and Channel Access or the dbpf command used to put the name of the routine into the record’s SNAM field. The record will look up the symbol name in the symbol table whenever the SNAM field gets modified. The same routine name can even be used as the vxWorks symbol lookup returns the latest version of the code to have been loaded.