The heart of an ONSPEC system is the ONSPEC Real-time Database, which includes ONSPEC Simple Data Tables and Complex Data Tables.
Each element in the ONSPEC Simple Data Tables can be considered as a register that saves the value of that specific ONSPEC variable.
ONSPEC variables may be represented as real numbers, integer numbers, discrete digital data or a text string. In addition to its value, an ONSPEC variable is saved with its status flags indicating the quality and condition of the data.
The data coming into ONSPEC is obtained from a variety of sources. The data in the data tables may be updated by I/O templates, modified by OCL calculations, controller output from ONSPEC Control Package, user programs and functions, or an operator entry.
ONSPEC data tables can be constructed, modified, deleted, and managed by using the ONSPEC configurator, ONConfig.
Simple Data Tables: Analog
The simple analog data tables size is between 130 to 16,344.
EUR – Engineering Units RealEngineering Units Real values are scaled from the raw values obtained from the process computer into actual engineering units. These values may have a range of 10-307 to 10307. Each EUR entry requires 8 bytes for storage.
EUF – Engineering Units FlagsEngineering Units Flags are associated with each of the EUR values. The EUF is a set of flags which represents the current status and validity of the EUR value. The flags are stored in a single byte for each EUF. EUF is transparent to the user.
EUI – Engineering Units IntegerEngineering Units Integer values are scaled from the raw values into actual engineering units, which may have a range of -2147483649 to 2147483648. The value reflects the current scan data. Each EUI entry requires 4 bytes for storage.
EUFI – Engineering Units Flags IntegerEngineering Units Flags Integer are associated with each of the EUI values. The EUFI is a set of flags which represents the current status and validity of the EUI value. The flags are stored as a byte for each EUFI. EUFI is transparent to the user.
STR – StringThe STR table allows for displaying alphanumeric characters on an ONSPEC display. An STR table location can hold up to 8 characters; any combination of letters, numbers and special characters. If you want to display more than 8 characters, the next 8 characters are automatically assigned to the next sequential STR table location.
Simple Data Tables: Digital
The simple digital data tables each contain 130 to 16,344 data table entries.
DII - Digital InputsDigital Inputs have only two possible states. The digital input value is stored with a set of flags which represent the current status and validity of the digital state. The flags are stored in a single byte for each DII entry.
DOO - Digital OutputsDigital Outputs have only two possible states. The digital output value is stored with a set of flags which represent the current status and validity of the digital state. The flags are stored in a single byte for each DOO entry.
FLG - Digital FlagsDigital Flags or Internal Flags. Conditional information can be passed between areas and/or displayed through the use of internal two state flags. Associated with these flags is a set of flags which represent the current status and validity for the internal flag. The flags are stored in a single byte for each FLG entry.
Notice that the DII, DOO and FLG tables may be used interchangeably if desired. They are identical in their function and use. For example, if you run out of room in the DOO table, you may continue with the DII table. Also, these tables do not have flags associated with them; their status is stored within them.
The alarm status is stored directly with the current value.
Simple Data Tables: Analog
SCA - Raw Scan ValuesRaw Scan Values are scaled from the raw values into actual engineering units, which may have a range of Ø to 4294967296. The value reflects the current scan data. Each SCA entry requires 4 bytes for storage. There are no status flags associated with raw scan values, which means it is not possible to alarm on these points.
OUT - Analog Output ValuesAnalog Output Values are scaled from the raw values into actual engineering units, which may have a range of Ø to 4294967296. The value reflects the current scan data. Each OUT entry requires 4 bytes for storage.
Neither the SCA nor the OUT tables have associated alarms because they do not have status values.
LOG - Display Reference TypeCan be used to change the ONSPEC display. LOGnnn (where nnn is a display number from 1 - 999) can be used in place of a ONSPEC location when the situation allows it to be changed. Changing LOGnnn loads display nnn into ONSPEC.
SUM, HIS, TRA - Alarm related Reference Types.SUMnn, HISnn, and TRAnn (where nn is the index into their corresponding pages) reference the associated Summary, History, and Operator Tracking alarms. The assigned offset to each of these Reference Types corresponds to the position within the alarm Summary, History, and Operator Tracking.
Ex: SUM1 is the most recent alarm in the Summary.
HIS10 is the 10th past alarm recorded in the alarm History.
Note:There are related OCL variables:
$ALARMINC Defines the number of alarms that constitute a Summary, History, and Operator Tracking page.
$ALARMPAGE Defines the alarm page which determines the base for the offset into the Summary, History, and Operator Tracking.
The formula ($ALARMPAGE - 1) * $ALARMINC + nn determines the actual alarm you are referencing.
$ALARMINC = 10
$ALARMPAGE = 2
You are displaying HIS5
The result is you are actually displaying the 15th past Historical alarm.
See the Alarm Summary, History, and Operator Tracking sections, as well as the Pre-defined Variables section in the OCL User Guide.
In addition to the above, there are several Complex Data Tables that can be used along with ONSPEC Simple Data Tables. These tables save useful information in their special data structures. ONSPEC Complex Data Tables can be constructed, modified, deleted, and managed by using ONConfig. These tables are:
TagsIn process control applications, tags are used to name process variables from the field. ONSPEC tags can be considered as another naming option for ONSPEC variables in the ONSPEC Database. It is a good idea to use the same tag name for the variables in the instrument and in ONSPEC.
ONSPEC tags are also used to (1) provide message and variable description for ONSPEC alarms; (2) define historical data collection criteria; and (3) provide linkage to external programs such as ONView.
Data Buffers (Trends)Data Buffers, sometimes referred to as Trends, provide a means of storing values for use in trend primitives and instruments. With these stored values you can view a graphic representation of the activity of a selected variable in ONSPEC displays. Notice that these trends are for short term applications. For long-term trends, you should use ONSPEC historical files and ONView.
AlarmsONSPEC Alarms provide many useful features for monitoring alarm conditions, sending alarm messages, and triggering alarm actions.
Control Blocks (PIDs)ONSPEC Control Blocks (PIDs) are used to (1) provide a data structure for pre-defined faceplates shown in ONSPEC displays; (2) provide a data structure for the controllers in ONSPEC Control Pack software; and (3) provide a data structure for user created advanced control packages.