The normal use for the long output or "longout" record type is to store long integer values of up to 32 bits and write them to hardware devices. The
Soft Channel device support layer can also be used to write values to other records via database or channel access links. The OUT field determines how the record is used. The record supports alarm limits and graphics and control limits.
The fields in this record fall into the following categories:
The longout record has the standard fields for specifying under what circumstances it will be processed. These fields are listed in "Scan Fields". In addition, "Scanning Specification" explains how these fields are used. Note that I/O event scanning is only supported for those card types that interrupt.
The record must specify where the desired output originates, i.e., the 32 bit integer value it is to write. The output mode select (OMSL) field determines whether the output originates from another record or from database access. When set to
closed_loop, the desired output is retrieved from the link specified in the desired output (DOL) field (which can specify either a database or channel access link) and placed into the VAL field. When set to
supervisory, the desired output can be written into the VAL field via dpPuts at run-time.
A third type of value for the DOL field is a constant in which case, when the record is initialized, the VAL field will be initialized with this constant value.
The VAL field's value will be clipped within limits specified in the fields DRVH and DRVL if these have been configured by the database designer:
DRVL <= VAL <= DRVH
Note: These limits are only enforced as long as DRVH > DRVL. If they are not set or DRVH <= DRVL they will not be used.
Field Summary Type DCT Default Read Write CA PP DOL Desired Output Loc INLINK Yes Yes Yes No OMSL Output Mode Select MENU (menuOmsl) Yes Yes Yes No DRVH Drive High Limit LONG Yes Yes Yes Yes DRVL Drive Low Limit LONG Yes Yes Yes Yes VAL Desired Output LONG Yes Yes Yes Yes
The OUT link field determines where the record is to send its output. For records that write values to hardware devices, the OUT output link field must specify the address of the I/O card, and the DTYP field must specify the name of the corresponding device support module.
For soft records, the OUT output link can be a constant, a database link, or a channel access link. If the link is a constant, the result is no output. The DTYP field must then specify the
Soft Channel device support routine.
See "Address Specification" for information on the format of hardware addresses and database links.
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
These parameters are used to present meaningful data to the operator. They display the value and other parameters of the long output either textually or graphically.
EGU is a string of up to 16 characters describing the units that the long output measures. It is retrieved by the
get_units record support routine.
The HOPR and LOPR fields set the upper and lower display limits for the VAL, HIHI, HIGH, LOW, and LOLO fields. Both the
get_control_double record support routines retrieve these fields.
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 EGU Engineering Units STRING  Yes Yes Yes No HOPR High Operating Range LONG Yes Yes Yes No LOPR Low Operating Range LONG Yes Yes Yes No NAME Record Name STRING  No Yes No No DESC Descriptor STRING  Yes Yes Yes No
The possible alarm conditions for long inputs are the SCAN, READ, INVALID, and limit alarms. The SCAN and READ alarms are not configurable by the user because their severity is always MAJOR. The INVALID alarm is called by the record support routine when the record or device support routines cannot write the record's output. The IVOA field specifies the action to take in this case.
The limit alarms are configured by the user in the HIHI, LOLO, HIGH, and LOW fields using floating-point values. For each of these fields, there is a corresponding severity field which can be either NO_ALARM, MINOR, or MAJOR. The HYST field contains the alarm deadband around each limit alarm.
See the See "Alarm Specification" for a complete explanation of alarms and these fields. For an explanation of the IVOA and IVOV fields, see "Output Records". "Alarm Fields" lists other fields related to a alarms that are common to all record types.
Field Summary Type DCT Default Read Write CA PP HIHI Hihi Alarm Limit LONG Yes Yes Yes Yes HIGH High Alarm Limit LONG Yes Yes Yes Yes LOW Low Alarm Limit LONG Yes Yes Yes Yes LOLO Lolo Alarm Limit LONG Yes Yes Yes Yes HHSV Hihi Severity MENU (menuAlarmSevr) Yes Yes Yes Yes HSV High Severity MENU (menuAlarmSevr) Yes Yes Yes Yes LSV Low Severity MENU (menuAlarmSevr) Yes Yes Yes Yes LLSV Lolo Severity MENU (menuAlarmSevr) Yes Yes Yes Yes HYST Alarm Deadband LONG Yes Yes Yes No IVOA INVALID output action MENU (menuIvoa) Yes Yes Yes No IVOV INVALID output value LONG Yes Yes Yes No
These parameters are used to determine when to send monitors placed on the value field. The monitors are sent when the value field exceeds the last monitored field by the appropriate delta. If these fields have a value of zero, everytime the value changes, a monitor will be triggered; if they have a value of -1, everytime the record is scanned, monitors are triggered. The ADEL field is the delta for archive monitors, and the MDEL field is the delta for all other types of monitors. See "Monitor Specification" for a complete explanation of monitors.
Field Summary Type DCT Default Read Write CA PP ADEL Archive Deadband LONG Yes Yes Yes No MDEL Monitor Deadband LONG Yes Yes Yes No
The LALM, MLST, and ALST fields are used to implement the hysteresis factors for monitor callbacks. Only if the difference between these fields and the corresponding value field is greater than the appropriate delta (MDEL, ADEL, HYST)--only then are monitors triggered. For instance, only if the difference between VAL and MLST is greater than MDEL are the monitors triggered for VAL.
Field Summary Type DCT Default Read Write CA PP LALM Last Value Alarmed LONG No Yes No No ALST Last Value Archived LONG No Yes No No MLST Last Val Monitored LONG No Yes No No
The following fields are used to operate the long output in the simulation mode. See "Fields Common to Many Record Types" for more information on the simulation mode fields
Field Summary Type DCT Default Read Write CA PP SIOL Sim Output Specifctn OUTLINK Yes 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
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 VAL is initialized to its value 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.
See next section.
Sets the upper display and lower display limits for a field. If the field is VAL, HIHI, HIGH, LOW, or LOLO, 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 upper control and the lower control limits for a field. If the field is VAL, HIHI, HIGH, LOW, or LOLO, 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_alarm_limit = HIHI upper_warning_limit = HIGH lower_warning_limit = LOW lower_alarm_limit = LOLO
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 "Output Records" for more information. If the return status of recGblGetLinkValue is zero then UDF is set to FALSE.
Check alarms. This routine checks to see if the new VAL causes the alarm status and severity to change. If so, NSEV, NSTA and LALM are set. It also honors the alarm hysteresis factor (HYST). Thus the value must change by more than HYST before the alarm status and severity is lowered.
Check severity and write the new value. See "Invalid Alarm Output Action" for information on how INVALID alarms affect output records.
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 ADEL and MDEL conditions are met.
NSEV and NSTA are reset to 0.
Scan forward link if necessary, set PACT FALSE, and return.
Each long output record must have an associated set of device support routines. The primary responsibility of the device support routines is to output a new value whenever write_longout 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
Device support consists of the following routines:
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.
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.
This routine is optional. If provided, it is called by the record support
get_ioint_info(int cmd,struct 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.
This routine must output a new value. It returns the following values:
Soft Channel module writes the current value of VAL.
If the OUT link type is PV_LINK, then dbCaAddInlink is called by
write_longout calls recGblPutLinkValue to write the current value of VAL.
See "Soft Output" for a further explanation.