Multi-Bit Binary Input Record (mbbi)

The normal use for the multi-bit binary input record is to read contiguous, multiple bit inputs from hardware. The binary value represents a state from a range of up to 16 states. The multi-bit input record interfaces with devices that use more than one bit.

Most device support modules obtain values from hardware and place the value in RVAL. For these device support modules record processing uses RVAL to determine the current state (VAL is given a value between 0 and 15). Device support modules may optionally read a value directly into VAL.

Soft device modules are provided to obtain input via database or channel access links or via dbPutField or dbPutLink requests. Two soft device support modules are provided: Soft Channel allows VAL to be an arbitrary unsigned short integer. Raw Soft Channel reads the value into RVAL just like normal device support modules.

Parameter Fields

The record-specific fields are described below, grouped by functionality.

Scan Parameters

The multi-bit binary input record has the standard fields for specifying under what circumstances it will be processed. These fields are listed in Scan Fields.

Read and Convert Parameters

The device support routines obtain the record’s input from the device or link specified in the INP field. For records that obtain their input from devices, the INP field must contain the address of the I/O card, and the DTYP field must specify the proper device support module. Be aware that the address format differs according to the I/O bus used.

Two soft device support modules can be specified in DTYP Soft Channel and Raw Soft Channel.

Raw Soft Channel reads the value into RVAL, upon which the normal conversion process is undergone. Soft Channel reads any unsigned integer directly into VAL. For a soft mbbi record, the INP field can be a constant, a database, or a channel access link. If INP is a constant, then the VAL is initialized to the constant value but can be changed at run-time via dbPutField or dbPutLink.

MASK is used by the raw soft channel read routine, and by typical device support read routines, to select only the desired bits when reading the hardware register. It is initialized to ((1 << NOBT) - 1) by record initialization. The user can configure the NOBT field, but the device support routines may set it, in which case the value given to it by the user is simply overridden. The device support routines may also override MASK or shift it left by SHFT bits. If MASK is non-zero, only the bits specified by MASK will appear in RVAL.

Unless the device support routine specifies no conversion, RVAL is used to determine VAL as follows:

  1. RVAL is assigned to a temporary variable – rval = RVAL

  2. rval is shifted right SHFT number of bits.

  3. A match is sought between rval and one of the state value fields, ZRVL-FFVL.

Each of the fields, ZRVL-FFVL, represents one of the possible sixteen states (not all sixteen have to be used).

Alternatively, the input value can be read as a string, in which case, a match is sought with one of the strings specified in the ZRST-FFST fields. Then RVAL is set equal to the corresponding value for that string, and the conversion process occurs.

Field

Summary

Type

DCT

Default

Read

Write

CA PP

VAL

Current Value

ENUM

Yes

Yes

Yes

Yes

INP

Input Specification

INLINK

Yes

Yes

Yes

No

MASK

Hardware Mask

ULONG

No

Yes

No

No

NOBT

Number of Bits

USHORT

Yes

Yes

No

No

RVAL

Raw Value

ULONG

No

Yes

Yes

Yes

SHFT

Shift

USHORT

Yes

Yes

Yes

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

Operator Display Parameters

These parameters are used to present meaningful data to the operator. They display the value and other parameters of the mbbi record either textually or graphically. The ZRST-FFST fields contain strings describing one of the possible states of the record. The get_enum_str and get_enum_strs record routines retrieve these strings for the operator. Get_enum_str gets the string corresponding to the value set 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 [61]

No

Yes

No

No

DESC

Descriptor

STRING [41]

Yes

Yes

Yes

No

ZRST

Zero String

STRING [26]

Yes

Yes

Yes

Yes

ONST

One String

STRING [26]

Yes

Yes

Yes

Yes

TWST

Two String

STRING [26]

Yes

Yes

Yes

Yes

THST

Three String

STRING [26]

Yes

Yes

Yes

Yes

FRST

Four String

STRING [26]

Yes

Yes

Yes

Yes

FVST

Five String

STRING [26]

Yes

Yes

Yes

Yes

SXST

Six String

STRING [26]

Yes

Yes

Yes

Yes

SVST

Seven String

STRING [26]

Yes

Yes

Yes

Yes

EIST

Eight String

STRING [26]

Yes

Yes

Yes

Yes

NIST

Nine String

STRING [26]

Yes

Yes

Yes

Yes

TEST

Ten String

STRING [26]

Yes

Yes

Yes

Yes

ELST

Eleven String

STRING [26]

Yes

Yes

Yes

Yes

TVST

Twelve String

STRING [26]

Yes

Yes

Yes

Yes

TTST

Thirteen String

STRING [26]

Yes

Yes

Yes

Yes

FTST

Fourteen String

STRING [26]

Yes

Yes

Yes

Yes

FFST

Fifteen String

STRING [26]

Yes

Yes

Yes

Yes

Alarm Parameters

The possible alarm conditions for multi-bit binary inputs are the SCAN, READ, and state alarms. 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 AFTC field sets the time constant on a low-pass filter that delays the reporting of limit alarms until the signal has been within the alarm range for that number of seconds (the default AFTC value of zero retains the previous behavior).

The unknown state severity (UNSV) field, 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 rval.

The change of state severity (COSV) field triggers an alarm when any change of state occurs, if set to MAJOR or MINOR.

The other fields, when set to MAJOR or MINOR, trigger an alarm when VAL equals the corresponding state.

See Alarm Specification for a complete explanation of record alarms and of the standard 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

UNSV

Unknown State Severity

MENU menuAlarmSevr

Yes

Yes

Yes

Yes

COSV

Change of State Svr

MENU menuAlarmSevr

Yes

Yes

Yes

Yes

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 Severity

MENU menuAlarmSevr

Yes

Yes

Yes

Yes

AFTC

Alarm Filter Time Constant

DOUBLE

Yes

Yes

Yes

No

Run-time Parameters

These parameters are used by the run-time code for processing the multi-bit binary input.

ORAW is used by record processing to hold the prior RVAL for use in determining when to post a monitor event for the RVAL field.

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.

Field

Summary

Type

DCT

Default

Read

Write

CA PP

ORAW

Prev Raw Value

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

Simulation Mode Parameters

The following fields are used to operate the record in simulation mode.

If SIMM (fetched through SIML) is YES or RAW, the record is put in SIMS severity and the value is fetched through SIOL (buffered in SVAL). If SIMM is YES, SVAL is written to VAL without conversion, if SIMM is RAW, SVAL is trancated to RVAL and converted. 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 Input 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 menuSimm

No

Yes

Yes

No

SIOL

Simulation Input Link

INLINK

Yes

Yes

Yes

No

SVAL

Simulation Value

ULONG

No

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

Record Support

Record Support Routines

init_record

This routine initializes SIMM with the value of SIML if SIML type is CONSTANT link or creates a channel access link if SIML type is PV_LINK. SVAL is likewise initialized if SIOL is CONSTANT or PV_LINK.

This routine next checks to see that device support is available and a device support read routine is defined. If either does not exist, an error message is issued and processing is terminated.

Clears MASK and then sets the NOBT low order bits.

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.

process

See next section.

special

Calls init_common to compute SDEF when any of the fields ZRVL, … FFVL change value.

get_enum_str

Retrieves ASCII string corresponding to VAL.

get_enum_strs

Retrieves ASCII strings for ZRST,…FFST.

put_enum_str

Checks if string matches ZRST,…FFST and if it does, sets VAL.

Record Processing

Routine process implements the following algorithm:

  1. 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.

  2. readValue is called. See “Input Records” for more information.

  3. If PACT has been changed to TRUE, the device support read routine has started but has not completed reading a new input value. In this case, the processing routine merely returns, leaving PACT TRUE.

  4. Convert:

    • status=read_mbbi

    • PACT = TRUE

    • recGblGetTimeStamp() is called.

    • If status is 0, then determine VAL

      • Set rval = RVAL

      • Shift rval right SHFT bits

    • If at least one state value is defined

      • Set UDF to TRUE

    • If RVAL is ZRVL,…,FFVL then set

      • VAL equals index of state

      • UDF set to FALSE

    • Else set VAL = undefined

      • Else set VAL = RVAL

    • Set UDF to FALSE

      • If status is 1, return 0

      • If status is 2, set status = 0

  5. 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.

  6. 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 are checked whenever other monitors are invoked.

    • NSEV and NSTA are reset to 0.

  7. Scan forward link if necessary, set PACT FALSE, and return.

Device Support

Fields Of Interest To Device Support

Each input record must have an associated set of device support routines.

The primary responsibility of the device support routines is to obtain a new raw input value whenever read_mbbi 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

UDF

Undefined

UCHAR

Yes

1

Yes

Yes

Yes

NSEV

New Alarm Severity

MENU menuAlarmSevr

No

Yes

No

No

NSTA

New Alarm Status

MENU menuAlarmStat

No

Yes

No

No

NOBT

Number of Bits

USHORT

Yes

Yes

No

No

VAL

Current Value

ENUM

Yes

Yes

Yes

Yes

INP

Input Specification

INLINK

Yes

Yes

Yes

No

RVAL

Raw Value

ULONG

No

Yes

Yes

Yes

MASK

Hardware Mask

ULONG

No

Yes

No

No

SHFT

Shift

USHORT

Yes

Yes

Yes

No

Device Support Routines

Device support consists of the following routines:

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.

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

init_record(precord)

This routine is optional. If provided, it is called by the record support init_record() routine. If it uses MASK, it should shift it as necessary and also give SHFT a value.

get_ioint_info

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 I/O Event scanner.

read_mbbi

read_mbbi(precord)

This routine must provide a new input value. It returns the following values:

  • 0: Success. A new raw value is placed in RVAL. The record support module determines VAL from RVAL, SHFT, and ZEVL … FFVL.

  • 2: Success, but don’t modify VAL.

  • Other: Error.

Device Support For Soft Records

Two soft device support modules Soft Channel and Raw Soft Channel are provided for multi-bit binary input records not related to actual hardware devices. The INP link type must be either CONSTANT, DB_LINK, or CA_LINK.

Soft Channel

read_mbbi always returns a value of 2, which means that no conversion is performed.

If the INP link type is constant, then the constant value is stored into VAL by init_record(), and UDF is set to FALSE. VAL can be changed via dbPut requests. If the INP link type is PV_LINK, then dbCaAddInlink is called by init_record().

read_mbbi calls recGblGetLinkValue to read the current value of VAL. See Soft Input.

If the return status of recGblGetLinkValue is zero, then read_mbbi sets UDF to FALSE. The status of recGblGetLinkValue is returned.

Raw Soft Channel

This module is like the previous except that values are read into RVAL, VAL is computed from RVAL, and read_mbbi returns a value of 0. Thus the record processing routine will determine VAL in the normal way.