The normal use for the mbbo record type is to send a binary value (representing one of up to 16 states) to a Digital Output module. It is used for any device that uses more than one contiguous bit to control it. The mbbo record can also be used to write discrete values to other records via database or channel access links.
The record-specific fields are described below, grouped by functionality.
The mbbo 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 multi-bit binary output record, like all output records, must specify where its output originates. The output mode select (OMSL) field determines whether the output originates from another record or from database access (i.e., the operator). 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 DOL field is ignored and the current value of VAL is simply written. VAL can be changed via dpPuts at run-time when OMSL is
supervisory. The DOL field can also be a constant, in which case the VAL field is initialized to the constant value. If DOL is a constant, OMSL cannot be set to
The VAL field itself usually consists of an index that specifies one of the states. The actual output written is the value of RVAL, which is converted from VAL following the routine explained in the next section. However, records that use the
Soft Channel device support module write the VAL field's value without any conversion.
Field Summary Type DCT Default Read Write CA PP OMSL Output Mode Select MENU (menuOmsl) Yes Yes Yes No DOL Desired Output Loc INLINK Yes Yes Yes No VAL Desired Value ENUM Yes Yes Yes Yes
The device support routines write the desired output to the location specified in the OUT field. If the record uses soft device support, OUT can contain a constant, a database link, or a channel access link; however, if OUT is a constant, no value will be written.
For records that write their values to hardware devices, the OUT output link must specify the address of the I/O card, and the DTYP field must specify the corresponding device support module. Be aware that the address format differs according to the I/O bus used. See "Address Specification" for information on the format of hardware addresses.
For mbbo records that write to hardware, the value written to the output location is the value contained in RVAL, which is converted from VAL, VAL containing an index of one of the 16 states (0-15). RVAL is then set to the corresponding state value, the value in one of the fields ZRVL through FFVL. Then this value is shifted left according to the number in the SHFT field so that the value is in the correct position for the bits being used (the SHFT value is set by device support and is not configurable by the user).
The state value fields ZRVL through FFVL must be configured by the user before run-time. When the state values are not defined, the states defined (SDEF) field is set to FALSE at initialization time by the record routines. When SDEF is FALSE, then the record processing routine does not try to find a match, RVAL is set equal to VAL, the bits are shifted using the number in SHFT, and the value is written thus.
If the OUT output link specifies a database link, channel access link, or constant, then the DTYP field must specify either one of the two soft device support modules--
Soft Channel or
Raw Soft Channel.
Channel writes the value of VAL to the output link, without any conversion, while
Raw Soft Channel writes the value from RVAL after it has undergone the above conversion. See "Address Specification" for information on specifying links.
Note also that when a string is retrieved as the desired output, a record support routine is provided (
put_enum_str()) that will check to see if the string matches one of the strings in the ZRST through FFST fields. If a match is found, RVAL is set equal to the corresponding state value of that string.
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 RVAL Raw Value ULONG No Yes Yes Yes SHFT Shift USHORT Yes Yes Yes No SDEF States Defined SHORT No Yes No No ZRVL Zero Value ULONG Yes Yes Yes Yes ONVL One Value ULONG Yes Yes Yes Yes TWVL Two Value ULONG Yes Yes Yes Yes THVL Three Value ULONG Yes Yes Yes Yes FRVL Four Value ULONG Yes Yes Yes Yes FVVL Five Value ULONG Yes Yes Yes Yes SXVL Six Value ULONG Yes Yes Yes Yes SVVL Seven Value ULONG Yes Yes Yes Yes EIVL Eight Value ULONG Yes Yes Yes Yes NIVL Nine Value ULONG Yes Yes Yes Yes TEVL Ten Value ULONG Yes Yes Yes Yes ELVL Eleven Value ULONG Yes Yes Yes Yes TVVL Twelve Value ULONG Yes Yes Yes Yes TTVL Thirteen Value ULONG Yes Yes Yes Yes FTVL Fourteen Value ULONG Yes Yes Yes Yes FFVL Fifteen Value ULONG Yes Yes Yes Yes
These parameters are used to present meaningful data to the operator. These fields are used to display the value and other parameters of the mbbo record either textually or graphically. The ZRST-FFST fields contain strings describing each of the corresponding states. The
get_enum_strs() record routines retrieve these strings for the operator.
get_enum_str() gets the string corresponding to the value in VAL, and
get_enum_strs() retrieves all the strings.
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  No Yes No No DESC Descriptor STRING  Yes Yes Yes No ZRST Zero String STRING  Yes Yes Yes Yes ONST One String STRING  Yes Yes Yes Yes TWST Two String STRING  Yes Yes Yes Yes THST Three String STRING  Yes Yes Yes Yes FRST Four String STRING  Yes Yes Yes Yes FVST Five String STRING  Yes Yes Yes Yes SXST Six String STRING  Yes Yes Yes Yes SVST Seven String STRING  Yes Yes Yes Yes EIST Eight String STRING  Yes Yes Yes Yes NIST Nine String STRING  Yes Yes Yes Yes TEST Ten String STRING  Yes Yes Yes Yes ELST Eleven String STRING  Yes Yes Yes Yes TVST Twelve String STRING  Yes Yes Yes Yes TTST Thirteen String STRING  Yes Yes Yes Yes FTST Fourteen String STRING  Yes Yes Yes Yes FFST Fifteen String STRING  Yes Yes Yes Yes
The possible alarm conditions for multi-bit binary outputs are the SCAN, READ, INVALID, and state alarms. The SCAN and READ alarms are called by the support modules and are not configurable by the user, as their severity is always MAJOR.
The IVOA field specifies an action to take from a number of possible choices when the INVALID alarm is triggered. The IVOV field contains a value to be written once the INVALID alarm has been triggered if
Set output to IVOV has been chosen in the IVOA field. The severity of the INVALID alarm is not configurable by the user.
The state alarms are configured in the below severity fields. These fields have the usual possible values for severity fields: NO_ALARM, MINOR, and MAJOR.
The unknown state severity field (UNSV), if set to MINOR or MAJOR, triggers an alarm when the record support routine cannot find a matching value in the state value fields for VAL or when VAL is out of range.
The change of state severity field (COSV) triggers an alarm when the record's state changes, if set to MAJOR or MINOR.
The state severity (ZRSV-FFSV) fields, when set to MAJOR or MINOR, trigger an alarm when VAL equals the corresponding field.
See "Alarm Specification" for a complete explanation of discrete alarms and these fields. See "Invalid Alarm Output Action" for an explanation of the IVOA and IVOV fields. "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 UNSV Unknown State Sevr MENU (menuAlarmSevr) Yes Yes Yes Yes COSV Change of State Sevr MENU (menuAlarmSevr) Yes Yes Yes Yes IVOA INVALID outpt action MENU (menuIvoa) Yes Yes Yes No IVOV INVALID output value USHORT Yes Yes Yes No ZRSV State Zero Severity MENU (menuAlarmSevr) Yes Yes Yes Yes ONSV State One Severity MENU (menuAlarmSevr) Yes Yes Yes Yes TWSV State Two Severity MENU (menuAlarmSevr) Yes Yes Yes Yes THSV State Three Severity MENU (menuAlarmSevr) Yes Yes Yes Yes FRSV State Four Severity MENU (menuAlarmSevr) Yes Yes Yes Yes FVSV State Five Severity MENU (menuAlarmSevr) Yes Yes Yes Yes SXSV State Six Severity MENU (menuAlarmSevr) Yes Yes Yes Yes SVSV State Seven Severity MENU (menuAlarmSevr) Yes Yes Yes Yes EISV State Eight Severity MENU (menuAlarmSevr) Yes Yes Yes Yes NISV State Nine Severity MENU (menuAlarmSevr) Yes Yes Yes Yes TESV State Ten Severity MENU (menuAlarmSevr) Yes Yes Yes Yes ELSV State Eleven Severity MENU (menuAlarmSevr) Yes Yes Yes Yes TVSV State Twelve Severity MENU (menuAlarmSevr) Yes Yes Yes Yes TTSV State Thirteen Sevr MENU (menuAlarmSevr) Yes Yes Yes Yes FTSV State Fourteen Sevr MENU (menuAlarmSevr) Yes Yes Yes Yes FFSV State Fifteen Sevr MENU (menuAlarmSevr) Yes Yes Yes Yes
These parameters are used by the run-time code for processing the multi-bit binary output.
MASK is used by device support routine to read the hardware register. Record support sets low order of MASK the number of bits specified in NOBT. Device support can shift this value.
The LALM field implements the change of state alarm severity by holding the value of VAL when the previous change of state alarm was issued.
MLST holds the value when the last monitor for value change was triggered.
SDEF is used by record support to save time if no states are defined; it is used for converting VAL to RVAL.
Field Summary Type DCT Default Read Write CA PP NOBT Number of Bits USHORT Yes Yes No No ORAW Prev Raw Value ULONG No Yes No No MASK Hardware Mask ULONG No Yes No No LALM Last Value Alarmed USHORT No Yes No No MLST Last Value Monitored USHORT No Yes No No SDEF States Defined SHORT No Yes No No
The following fields are used to operate the mbbo record 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.
MASK is cleared and then the NOBT low order bits are set.
If device support includes
init_record(), it is called.
init_common is then called to determine if any states are defined. If states are defined, SDEF is set to TRUE.
If device support returns success, VAL is then set from RVAL and UDF is set to FALSE.
See next section.
Computes SDEF when any of the fields ZRVL,...FFVL change value.
Fills in the values of struct valueDes so that they refer to VAL.
Retrieves ASCII string corresponding to VAL.
Retrieves ASCII strings for ZRST,...FFST.
Checks if string matches ZRST,...FFST and if it does, sets VAL.
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 not longer be called for this record. Thus error storms will not occur.
If PACT is FALSE
If DOL is DB_LINK and OMSL is CLOSED_LOOP
Get value from DOL
Set UDF to FALSE
Check for link alarm
If any state values are defined
If VAL > 15, then raise alarm and go to 4
Else using VAL as index set RVAL = one of ZRVL,...FFVL
Else set RVAL = VAL
Shift RVAL left SHFT bits
If PACT is FALSE, compute RVAL
If VAL is 0,...,15, set RVAL from ZRVL,...,FFVL
If VAL out of range, set RVAL = undefined
Status = write_mbbo
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.
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 MLST is not equal to VAL.
Monitors for RVAL and RBV are checked whenever other monitors are invoked.
NSEV and NSTA are reset to 0.
Scan forward link if necessary, set PACT FALSE, and return.
Each mbbo record must have an associated set of device support routines. The primary responsibility of the device support routines is to obtain a new raw mbbo value whenever write_mbbo is called. The device support routines are primarily interested in the following fields:
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's
init_record() routine. If MASK is used, it should be shifted if necessary and SHFT given a value.
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_mbbo calls recGblPutLinkValue to write the current value of VAL. See "Soft Output" for more information.
This module writes RVAL to the location specified in the output link. It returns a 0.
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