String Output Record (stringout)
The stringout record is used to write an arbitrary ASCII string of up to 40 characters to other records or software variables.
Parameter Fields
The record-specific fields are described below, grouped by functionality.
Scan Parameters
The 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 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 value: closed_loop
or supervisory
. If supervisory
is specified,
DOL is ignored, the current value of VAL is written, and the VAL can be changed
externally via dbPuts at run-time. If closed_loop
is specified, the VAL
field’s value is obtained from the address specified in the Desired Output
Link field (DOL) which can be either a database link or a channel access
link.
DOL can also be a constant, in which case VAL will be initialized to the
constant value. However to be interpreted as a constant instead of a CA link
the constant can only be numeric, so string output records are best initialized
by dirctly setting the VAL field. Note that if DOL is a constant, OMSL
cannot be closed_loop
.
Field |
Summary |
Type |
DCT |
Default |
Read |
Write |
CA PP |
---|---|---|---|---|---|---|---|
VAL |
Current Value |
STRING [40] |
Yes |
Yes |
Yes |
Yes |
|
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 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
monitor()
routine. There are two possible choices:
Operator Display Parameters
These parameters are used to present meaningful data to the operator. These fields are used to display the value and other parameters of the string output either textually or graphically.
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 |
Run-time Parameters
The old value field (OVAL) of the string input is used to implement value change monitors for VAL. If VAL is not equal to OVAL, then monitors are triggered.
Field |
Summary |
Type |
DCT |
Default |
Read |
Write |
CA PP |
---|---|---|---|---|---|---|---|
OVAL |
Previous Value |
STRING [40] |
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 |
Alarm Parameters
The possible alarm conditions for the string output record are the SCAN, READ, and INVALID alarms. The severity of the first two is always MAJOR and not configurable.
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.
Alarm Fields lists the fields related to alarms that are common to all record types.
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 |
Record Support
Record Support Routines
init_record
long (*init_record)(struct dbCommon *precord, int pass)
This routine initializes SIMM if SIML is a constant or creates a channel access link if SIML is PV_LINK. If SIOL is PV_LINK a channel access link is created.
This routine next checks to see that device support is available. The routine next checks to see if the device support write routine is defined. If either device support or the device support write routine does not exist, an error message is issued and processing is terminated.
If DOL is a constant, then the type double constant, if non-zero, is converted to a string and stored into VAL and UDF is set to FALSE. If DOL type is a PV_LINK then dbCaAddInlink is called to create a channel access link.
If device support includes init_record()
, it is called.
process
long (*process)(struct dbCommon *precord)
See “Record Processing”.
Record Processing
Routine process implements the following algorithm:
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.
If PACT is FALSE and OMSL is CLOSED_LOOP, recGblGetLinkValue is called to read the current value of VAL. See “Soft Output”. If the return status of recGblGetLinkValue is zero then UDF is set to FALSE.
Check severity and write the new value. See “Simulation Mode” and Invalid Output Action Fields for details on how the simulation mode and the INVALID alarm conditions affect output.
If PACT has been changed to TRUE, the device support write output routine has started but has not completed writing the new value. In this case, the processing routine merely returns, leaving PACT TRUE.
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 OVAL is not equal to VAL.
NSEV and NSTA are reset to 0.
Scan forward link if necessary, set PACT FALSE, and return.
Device Support
Fields Of Interest To Device Support
Each stringout output record must have an associated set of device support routines. The primary responsibility of the device support routines is to write a new value whenever write_stringout 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 |
|
VAL |
Current Value |
STRING [40] |
Yes |
Yes |
Yes |
Yes |
|
OUT |
Output Specification |
OUTLINK |
Yes |
Yes |
Yes |
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 *prec)
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_stringout
long write_stringout(stringoutRecord *prec)
This routine must output a new value. It returns the following values:
0: Success.
Other: Error.
Device Support for Soft Records
The Soft Channel
device support module writes the current value of VAL.
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.