NB: This manual documents a 20+ year old version of EPICS, see here for the EPICS 7 Record Reference documentation.
EPICS Record Reference Manual
Name | Summary | Description |
---|---|---|
INP | Input Link | This field is used by the device support routines to obtain input. For soft analog records it can be a constant, a database link, or a channel access link. |
DTYP | Device Type | DTYP specifies the name of the device support module that will input values. Each record type has its own set of device support routines. If a record type does not have any associated device support, DTYP is meaningless. |
RVAL | Raw Value | Whenever possible this field contains the raw data value exactly as it is obtained from the hardware or from the associated device driver and before it undergoes any conversions. The Soft Channel device support module reads values directly into VAL, bypassing this field. |
VAL | Value | This is the record's final value, after any needed conversions have been performed. |
SIMM | Simulation Mode | This field has either the value YES or NO. By setting this field to YES, the record can be switched into simulation mode of operation. While in simulation mode, input will be obtained from SIOL instead of INP. |
SIML | Simulation Mode Location | This field can be a constant, a database link, or a channel access link. If SIML is a database or channel access link, then SIMM is read from SIML. If SIML is a constant link then SIMM is initialized with the constant value but can be changed via dbPuts. |
SVAL | Simulation Value | This is the record's input value, in engineering units, when the record is switched into simulation mode, i.e. when SIMM is set to YES. |
SIOL | Simulation Value Location | This field can be a constant, a database link, or a channel access link. If SIOL is a database or channel access link, then SVAL is read from SIOL. If SIOL is a constant link then SVAL is initialized with the constant value but can be changed via dbPuts. |
SIMS | Simulation Mode Alarm Severity | When this record is in simulation mode, it will be put into alarm with this severity and a status of SIMM. |
Soft Channel
and Raw Soft Channel
. Both allow INP to be a constant, a database link, or a channel access link. The Soft Channel
device support module reads input directly into the VAL field and specifies that no conversion of any type should be performed. Thus, it allows the record to hold values corresponding to the C data type of the VAL field. Note that for soft input, RVAL is not used. The Raw Soft Channel
support module reads input into RVAL and asks that any specified conversions be performed.
The device support read routine normally calls recGblGetLinkValue()
which performs the following steps:
recGblGetLinkValue()
does nothing and returns with a status of zero.
dbGetLink()
is called to obtain a new input value. If dbGetLink
returns an error, a LINK_ALARM with a severity of INVALID_ALARM is raised. RecGblGetLinkValue()
returns the status returned by dbGetLink()
.
dbCaGetLink()
is called to obtain a new input value. If dbCaGetLink()
returns an error, a LINK alarm with a severity of INVALID is raised. RecGblGetLinkValue()
returns the status of dbCaGetLink()
.
recGblGetLinkValue()
is zero and the INP link type is not CONSTANT, then UDF is set to FALSE. The device support read routine normally returns the status of recGblGetLinkValue.
Normally input records contain a private readValue()
routine which performs the following steps:
recGblGetLinkValue()
to get a new value for SIMM if SIML is a DB_LINK or a CA_LINK.
Name | Summary | Description |
---|---|---|
OUT | Output Link | This field is used by the device support routines to decide where to send output. For soft records, it can be a constant, a database link, or a channel access link. If the link is a constant, the result is no output. |
DTYP | Device Type | DTYP specifies the name of the device support module that will receive values. Each record type has its own set of device support routines. If a record type does not have any associated device support, DTYP is meaningless. |
VAL | Value | This is the desired value before any conversions to raw output have been performed. |
OVAL | Output Value | OVAL is used to decide when to invoke monitors. Archive and value change monitors are invoked if OVAL is not equal to VAL. If a record type needs to make adjustments, OVAL is used to enforce the maximum rate of change limit before converting the desired value to a raw value. |
RVAL | Raw Value | Whenever possible this is the actual value sent to the hardware itself or to the associated device driver. |
RBV | Read Back Value | Whenever possible this is the actual read back value obtained from the hardware itself or from the associated device driver. |
DOL | Desired Output Location (an Input Link) | DOL can be a constant, a database link, or a channel access link. There is no device support associated with DOL. If DOL is a database or channel access link and OMSL is CLOSED_LOOP, then VAL is obtained from DOL. |
OMSL | Output Mode Select | This field has either the value SUPERVISORY or CLOSED_LOOP. DOL is used to determine VAL only if OMSL has the value CLOSED_LOOP. By setting this field the record can be switched between supervisory and closed loop mode of operation. While in closed loop mode, the VAL field cannot be set via dbPuts. |
OIF | Output Full or Incremental (analog output record only) | This field, which is only used when input is obtained from DOL, determines if the value obtained from DOL is an increment to add to the current VAL or is the actual VAL desired. |
SIMM | Simulation Mode | This field has either the value YES or NO. By setting this field to YES, the record can be switched into simulation mode of operation. While in simulation mode, output will be written to SIOL instead of OUT. |
SIML | Simulation Mode Location | This field can be a constant, a database link, or a channel access link. If SIML is a database or channel access link, then SIMM is read from SIML. If SIML is a constant link then SIMM is initialized with the constant value but can be changed via dbPuts. |
SIOL | Simulation Value Location | This field can be a constant, a database link, or a channel access link. If SIOL is a database or channel access link, then the output value is written to SIOL. If this link is a constant, the result is no output. |
SIMS | Simulation Mode Alarm Severity | When this record is in simulation mode, it will be put into alarm with this severity and a status of SIMM_ALARM. |
IVOA | Invalid Alarm Output Action | Whenever the record is put into INVALID alarm severity IVOA specifies an action. IVOA can be one of the following actions: Continue normally, Don't drive outputs, Set output equal to IVOV |
IVOV | Invalid Alarm Output Value, In Engineering Units | When new severity has been set to INVALID alarm and IVOA is "Set output equal to IVOV", then, VAL is set to IVOV and converted to RVAL before device support is called. |
Raw Soft Channel
support module writes the value associated with the RVAL field after conversion has been performed.The device support write routine normally calls recGblPutLinkValue which performs the following steps:
-- (SIMM = FALSE?) INP -> RVAL --(maybe convert) -> VAL
/
SIML -> SIMM
\
-- (SIMM = TRUE?) SIOL -> SVAL --(never convert) -> RVAL
Also, while the record is in simulation mode, there will be no calls to device support during record processing.
Normally output records contain a private writeValue()
routine which performs the following steps:
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