The Data Fanout or "dfanout" record is used to forward data to up to eight other records. It's similar to the fanout record except that the capability to forward data has been added to it. If has no associated device support.
The fields in this record can be classified into the following categories:
The data fanout 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.
Since the data fanout record supports no direct interfaces to hardware,
it cannot be scanned on I/O interrupt,
so its SCAN field cannot be I/O Intr.
The data fanout record must specify where the desired output value originates,
i.e.,
the data which is to be fowarded to the records in its output links.
The output mode select (OMSL) field determines whether the output originates from another record or from run-time 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 a channel access link,
and placed into the VAL field.
When set to supervisory,
the desired output can be written to the VAL field via dbPuts at run-time.
The DOL field can also be a constant in which case the VAL field is initialized to the constant value.
Note that there are no conversion parameters, so the desired output value undergoes no conversions before it is sent out to the output links.
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 VAL Desired Output DOUBLE Yes Yes Yes Yes
The OUTA-OUTH fields specify where VAL is to be sent. Each field that is to forward data must specify an address to another record. See "Address Specification" for information on specifying links.
The SELL, SELM, and SELN fields specify which output links are to be used.
SELM is a menu, with three choices:
Index Identifier Choice String 0 dfanoutSELM_All All 1 dfanoutSELM_Specified Specified 2 dfanoutSELM_Mask Mask
If SELM=="All", then all output links are used, and the values of SELL and SELN are ignored.
If SELM=="Specified", then the value of SELN is used to specify a single link which will be used. If SELN==0, then no link will be used; if SELN==1, then OUTA will be used, and so on.
SELN can either have its value set directly, or have its values retrieved from another EPICS PV. If SELL is a valid PV link, then SELN will be set to the values of the linked PV.
If SELM=="Mask", then SELN will be treated as a bit mask. If bit one of SELN is set, then OUTA will be used, if bit two is set, OUTB will be used. Thus if SELN==5, OUTC and OUTA will be used.
Field Summary Type DCT Default Read Write CA PP OUTA Output Spec A OUTLINK Yes Yes Yes No OUTB Output Spec B OUTLINK Yes Yes Yes No OUTC Output Spec C OUTLINK Yes Yes Yes No OUTD Output Spec D OUTLINK Yes Yes Yes No OUTE Output Spec E OUTLINK Yes Yes Yes No OUTF Output Spec F OUTLINK Yes Yes Yes No OUTG Output Spec G OUTLINK Yes Yes Yes No OUTH Output Spec H OUTLINK Yes Yes Yes No
These parameters are used to present meaningful data to the operator. They display the value and other parameters of the data fanout record either textually or graphically.
The EGU field can contain a string of up to 16 characters describing the value on the VAL field.
The HOPR and LOPR fields determine the upper and lower display limits for graphic displays and the upper and lower control limits for control displays.
They apply to the VAL,
HIHI,
HIGH,
LOW,
and LOLO fields.
The record support routines get_graphic_double or get_control_double retrieve HOPR and LOPR.
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 [16] Yes Yes Yes No HOPR High Operating Range DOUBLE Yes Yes Yes No LOPR Low Operating Range DOUBLE Yes Yes Yes No NAME Record Name STRING [61] No Yes No No DESC Descriptor STRING [41] Yes Yes Yes No
The possible alarm conditions for data fanouts are the SCAN, READ, INVALID, and limit alarms. The SCAN and READ alarms are called by the record routines. The limit alarms are configured by the user in the HIHI, LOLO, HIGH, and LOW fields using floating point values. The limit alarms apply only to the VAL field. The severity for each of these limits is specified in the corresponding field (HHSV, LLSV, HSV, LSV) and can be either NO_ALARM, MINOR, or MAJOR. In the hysteresis field (HYST) can be entered a number which serves as the deadband on the limit alarms.
See "Alarm Specification" for a complete explanation of alarms and these fields. "Alarm Fields" lists other fields related to alarms that are common to all record types.
Field Summary Type DCT Default Read Write CA PP HIHI Hihi Alarm Limit DOUBLE Yes Yes Yes Yes HIGH High Alarm Limit DOUBLE Yes Yes Yes Yes LOW Low Alarm Limit DOUBLE Yes Yes Yes Yes LOLO Lolo Alarm Limit DOUBLE 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 DOUBLE Yes Yes Yes No
These parameters are used to determine when to send monitors placed on the VAL field. These monitors are sent when the value field exceeds the last monitored fields by the specified deadband, ADEL for archivers monitors and MDEL for all other types of monitors. 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. See "Monitor Specification" for a complete explanation of monitors.
Field Summary Type DCT Default Read Write CA PP ADEL Archive Deadband DOUBLE Yes Yes Yes No MDEL Monitor Deadband DOUBLE Yes Yes Yes No
These parameters are used by the run-time code for processing the data fanout record. Ther are not configurable. They are used to implement the hysteresis factors for monitor callbacks.
Field Summary Type DCT Default Read Write CA PP LALM Last Value Alarmed DOUBLE No Yes No No ALST Last Value Archived DOUBLE No Yes No No MLST Last Val Monitored DOUBLE No Yes No No
init_record()This routine initializes all output links that are defined. Then it initializes DOL if DOL is a constant or a PV_LINK. When initializing the output links and the DOL link, a non-zero value is returned if an error occurs.
process()See next section.
get_units()The routine copies the string specified in the EGU field to the location specified by a pointer which is passed to the routine.
get_graphic_double()If the referenced field is VAL,
HIHI,
HIGH,
LOW,
or LOLO,
this routine sets the upper_disp_limit member of the dbr_grDouble structure to the HOPR and the lower_disp_limit member to the LOPR.
If the referenced field is not one of the above fields,
then recGblGetControlDouble() routine is called.
get_control_double()Same as the get_graphic_double routine except that it uses the dbr_ctrlDouble structure.
get_alarm_double()This sets the members of the dbr_alDouble structure to the specified alarm limits if the referenced field is VAL:
upper_alarm_limit = HIHI
upper_warning_limit = HIGH
lower_warning_limit = LOW
lower_alarm_limit = LOLO
If the referenced field is not VAL,
the recGblGetAlarmDouble() routine is called.
process() routine first retrieves a value for DOL and places it in VAL if OMSL is set to colsed loop mode.
If an error occurs,
then UDF is set to FALSE.recGblePutLinkValue() for each link.process() routine returns.
A -1 is returned if there was an error writing values to one of the output links.