See the EPICS Record Reference Manual for information on how to specify database links.
Field | Summary | Type | DCT | Initial | Access | Modify | Rec Proc Monitor |
---|---|---|---|---|---|---|---|
INPA | Input Link A | INLINK | Yes | 0 | No | No | N/A |
INPB | Input Link B | INLINK | Yes | 0 | No | No | N/A |
... | ... | ... | ... | ... | ... | ... | ... |
INPL | Input Link L | INLINK | Yes | 0 | No | No | N/A |
INAA | Input Link AA | INLINK | Yes | 0 | No | No | N/A |
INBB | Input Link BB | INLINK | Yes | 0 | No | No | N/A |
... | ... | ... | ... | ... | ... | ... | ... |
INFLL | Input Link LL | INLINK | Yes | 0 | No | No | N/A |
The CALC expression is actually converted to opcodes and stored in Reverse Polish Notation in the RPCL field. It is this expression which is ctually used to calculate VAL. The Reverse Polish expression is evaluated more efficiently at run-time than an infix expression would be. When CALC is changed at run-time, the record-support routine special()
will call a function to check it, and convert it to Reverse Polish Notation.
The record also has a second set of calculation-related fields described in Section 5, Output Parameters.
Field | Summary | Type | DCT | Initial | Access | Modify | Rec Proc Monitor | PP |
---|---|---|---|---|---|---|---|---|
CALC | Calculation | STRING[36] | Yes | 0 | Yes | Yes | Yes | No |
VAL | Value | DOUBLE | No | 0 | Yes | Yes | Yes | No |
RPCL | Reverse Polish | NOACCESS | No | 0 | No | No | N/A | No |
SVAL | String value | STRING (40) | No | 0 | Yes | Yes | Yes | No |
Expressions supported by the string calculation record can involve operands, algebraic operators and functions, trigonometric functions, relational operators, logical operators, string operators and functions, parentheses and commas, and the conditional '?:' operator. The expression can consist of any of these operators, as well as any of the values from the input fields, which are the operands.
Grouping of operands with parentheses is important not only to specify the order in which operations are to be done, but also to distinguish operands from operators whose names are spelled out, such as the logical operator 'AND'. The expression 'AANDB', which could have meant 'A AND B', will be misinterpreted by the parser, which will interpret 'AA' as the name of a string variable.
Field | Summary | Type | DCT | Initial | Access | Modify | Rec Proc Monitor | PP |
---|---|---|---|---|---|---|---|---|
A | Input Value A | DOUBLE | No | 0 | Yes | Yes/No* | Yes | Yes |
B | Input Value B | DOUBLE | No | 0 | Yes | Yes/No* | Yes | Yes |
... | ... | ... | ... | ... | ... | ... | ... | ... |
L | Input Value L | DOUBLE | No | 0 | Yes | Yes/No* | Yes | Yes |
AA | Input string AA | STRING (40) | No | 0 | Yes | Yes/No* | Yes | Yes |
BB | Input string BB | STRING (40) | No | 0 | Yes | Yes/No* | Yes | Yes |
... | ... | ... | ... | ... | ... | ... | ... | ... |
LL | Input string LL | STRING (40) | No | 0 | Yes | Yes/No* | Yes | Yes |
* If a valid input link is associated with this field, then it may not be modified.
There are a few special operands not associated with input fields, but
defined by the record (more exactly, defined by the calc engine the record uses
to evaluate expressions). All but RNDM
are constants.
PI | 3.141592654 |
D2R | Degrees to radians (PI/180) |
R2D | Radians to degrees (1/D2R) |
S2R | Arc seconds to radians (D2R/3600) |
R2S | Radians to arc seconds (1/S2R) |
RNDM | Random number between 0 and 1. |
Op | Description | Example |
---|---|---|
ABS | Absolute value (one-argument function) | ABS(A)
|
SQRT | Square root (one-argument function) (SQR is deprecated) | SQRT(A)
|
MIN | Minimum (two-or-more-argument function) | MIN(A,B,C)
|
MAX | Maximum (two-or-more-argument function) | MAX(A,B,C)
|
CEIL | Ceiling (one-argument function) | CEIL(A)
|
FLOOR | Floor (one-argument function) | FLOOR(A)
|
INT | Nearest integer (one-argument function) | INT(A)
|
NINT | Nearest integer (one-argument function) | NINT(A)
|
LOG | Log base 10 (one-argument function) | LOG(A)
|
LN | Natural logarithm (one-argument function) | LN(A)
|
LOGE | Deprecated synonym for 'LN' | LOGE(A)
|
EXP | Exponential function (unary) | EXP(A)
|
^ | Exponential (binary) (Same as '**'.) | A^B
|
** | Exponential (binary) (Same as '^'.) | A**B
|
+ | Addition (binary) | A+B
|
- | Subtraction (binary) | A-B
|
* | Multiplication (binary) | A*B
|
/ | Division (binary) | A/B
|
% | Modulo (binary) | A%B
|
- | Negate (unary) | -A
|
NOT | Negate (unary) | NOT A
|
>& | Max (binary) | A>?B
|
<& | Min (binary) | A<?B
|
Op | Description | Example |
---|---|---|
SIN | Sine (one-argument function) | SIN(A)
|
SINH | Hyperbolic sine (one-argument function) | SINH(A)
|
ASIN | Arc sine (one-argument function) | ASIN(A)
|
COS | Cosine (one-argument function) | COS(A)
|
COSH | Hyperbolic cosine (one-argument function) | COSH(A)
|
ACOS | Arc cosine (one-argument function) | ACOS(A)
|
TAN | Tangent (one-argument function) | TAN(A)
|
TANH | Hyperbolic tangent (one-argument function) | TANH(A)
|
ATAN | Arc tangent (one-argument function) | ATAN(A)
|
ATAN2 | Alternate form of arctangent (two-argument function) | ATAN2(A,B)
|
Op | Description | Example |
---|---|---|
>= | Greater than or equal to | A>=B
|
> | Greater than | A>B
|
<= | Less than or equal to | A<=B
|
< | Less than | A<B
|
!= | Not equal to (same as '#') | A!=B
|
# | Not equal to (same as '!=') | A#B
|
== | Equal to (same as '=') | A==B
|
= | Equal to (same as '==') | A=B
|
Op | Description | Example |
---|---|---|
&& | Logical AND | A&&B
|
|| | Logical OR | A||B
|
! | Logical NOT | !A
|
Op | Description | Example |
---|---|---|
| | Bitwise OR | A|B
|
OR | Bitwise OR | A OR B
|
& | Bitwise AND | A&B
|
AND | Bitwise AND | A AND B
|
XOR | Bitwise Exclusive OR | A XOR B
|
~ | One's Complement | ~A
|
<< | Left shift | A<<B
|
>> | Right shift | A>>B
|
<expression> ? <expression-true result> : <expression-false result>
Op | Description | Example | |
---|---|---|---|
MIN | Minimum lexically (two-or-more-argument function) | MAX('a','b','c') -> 'a'
| |
MAX | Maximum lexically (two-or-more-argument function) | MAX('a','b','c') -> 'c'
| |
INT | Find first number in string; return nearest integer (one-argument function) | INT('1.9') -> 1
| INT('abc1.9') -> 1
|
NINT | Find first number in string; return nearest integer (one-argument function) | NINT('1.9') -> 2
| NINT('abc1.9') -> 2
|
+ | Concatenate (binary) | 'a'+'b' -> 'ab'
| |
- | Delete first occurrence of substring (binary) | 'abca'-'a' -> 'bca'
| |
-| | Delete first occurrence of substring (binary) | 'abca'-'a' -> 'bca'
| |
|- | Delete last occurrence of substring (binary) | 'abca'-'a' -> 'abc'
| |
>= | Lexically greater than or equal (binary) | 'a'>='b' -> 0
| |
> | Lexically greater than (binary) | 'a'>'b' -> 0
| |
<= | Lexically less than or equal (binary) | 'a'<='b' -> 1
| |
< | Lexically less than (binary) | 'a'<'b' -> 1
| |
!= | Lexically not equal to (binary) | 'a'!='b' -> 1
| |
== | Lexically equal to (binary) | 'a'=='b' -> 0
| |
DBL | Convert argument to double (one-argument function) | DBL('1') -> 1.0
| DBL('abc1.23') -> 1.23
|
STR | Convert argument to string (one-argument function) | STR(1) -> '1.00000000'
| |
BYTE | Convert first character of string argument to double (one-argument function) | BYTE('abc') -> 97.0
| |
PRINTF | Return string constructed from format string and string or
double argument (two-argument function) (NOTE: '$P' is a synonym for PRINTF)
Allowed format indicators: %cdeEfgGiosuxX Disallowed indicators: * | PRINTF("%.2f",1.23) -> '1.23'
| |
SSCANF | Return string or double parsed from string argument according
to format string (two-argument function) (NOTE: '$S' is a synonym for SSCANF)
Allowed format indicators: %*[cdeEfgGhilosuxX Disallowed indicators: $npw | SSCANF('V=1.25', "%*2c%lf") -> 1.25
| |
[ | Substring | 'abcdef'[1,3] -> 'bcd'
| |
{ | Substring substitution | 'abcdef'{'cd','XX'} -> 'abXXef'
| |
" | String indicator | "abc"
| |
' | String indicator | 'abc'
|
Op | Description | Example |
---|---|---|
@ | Numeric array element. Regard the numeric fields A-L as an array whose elements are numbered 0-11, and return the element whose number follows. (unary) | @A
|
@@ | String array element. Regard the string fields AA-LL as an array of strings whose elements are numbered 0-11, and return the element whose number follows. (unary) | @@A
|
A + B + 10
A + B + 10
(A + B) < (C + D)
1
if (A+B) < (C+D)
0
if (A+B) >= (C+D)
(A+B)<(C+D)?E:F+L+10
E
if (A+B) < (C+D)
F+L+10
if (A+B) >= (C+D)
(A+B)<(C+D)?E
E
if (A+B) < (C+D)
(A+B) >= (C+D)
A&B
A
to integer
B
to integer
AND
of A
and B
A + "abc"
A + "abc1.2"
A + AA
(where AA = "abc1.2")
A
. The strings "abc"
and
"abc1.2"
will be converted implicitly to the number 0
.
A + DBL("abc1.2")
A + 1.2
. Explicit conversion to a number
(by DBL
, INT
, or NINT
) is more
aggressive than implicit conversion, and skips leading non-numeric characters.
"abc" + "def"
"abcdef"
.
PRINTF("abc%1.2f", A)
(where A = 1.2345)
"abc1.23"
.
NOTE: unlike the c-language function
printf(<format>,<arg1>,<arg2>,...),
this function accepts only one argument after the format string.
SSCANF(AA, "%*3c%lf")
(where AA = "abc1.2")
"1.20000000"
. (The format fragment
"%*3c"
directs sscanf to ignore three characters.)
BYTE("ABC")
65
, the ASCII code for "A" in decimal.
"abcdef"[2,4]
"cde"
. (The first character of the string
is numbered "0".)
"abcdef"[-2,-1]
"ef"
. (The last character of the string is
numbered "-1".)
"abcdef"["ab","ef"]
"cd"
. (If the first argument is a string,
it returns the index of the first character after a successful match,
or the first character in the string if no match was found. If the
second argument is a string, it returns the index of the last character
before a successful match, or the last character in the string if no
match was found.)
A==2 ? "yes" : "no"
"yes"
if A == 2
; otherwise, result
is "no"
.
"abcdef"{"bcd","dcb"}
"adcbef"
.
"abcdef"{"zzz","dcb"}
"abcdef"
. (If no match, then no replacement.)
"abcdef"[1,-2][1,-2]
"cd"
@0
A
. ("@0
"
is just another name for A
.)
@@0
@(A+B)
Every Time | write output every time record is processed. |
On Change | write output every time VAL changes, i.e., every time the result of the expression changes. |
When Zero | when record is processed, write output if VAL is zero. |
When Non-zero | when record is processed, write output if VAL is non-zero. |
Transition to Zero | when record is processed, write output only if VAL is zero and last value was non-zero. |
Transition to Non-zero | when record is processed, write output only if VAL is non-zero and last value was zero. |
Never | Don't write output ever. |
The DOPT field determines what data is written to the output link when the output is executed. The field is a menu field with two options: Use CALC or Use OCAL. If Use CALC is specified, when the record writes its output it will write the result of the expression in the CALC record, that is, it will write the value of the VAL [SVAL] field to a double [string] destination. If Use OCAL is specified, the record will instead write the result of the expression in the OCAL field, which is contained in the OVAL field (string result in the OSV) field. The OCAL field is exactly like the CALC field and has the same functionality: it can contain the string representation of an expression which is evaluated at run-time. Thus, if necessary, the record can use the result of the CALC expression to determine if data should be written and can use the result of the OCAL expression as the data to write.
If the OEVT field specifies a non-zero integer and the condition in the OOPT field is met, the record will post a corresponding event. If the ODLY field is non-zero, the record pauses for the specified number of seconds before executing the OUT link or posting the output event. During this waiting period the record is "active" and will not be processed again until the wait is over. The field DLYA is equal to 1 during the delay period. The resolution of the delay entry is 1/60 of a second (it uses the VxWorks tickLib).
The IVOA field specifies what action to take with the OUT link if the sCalcout record enters an INVALID alarm status. The options are Continue normally, Don't drive outputs, and Set output to IVOV. If the IVOA field is Set output to IVOV, the data entered into the IVOV field is written to the OUT link if the record alarm severity is INVALID.
Field | Summary | Type | DCT | Initial | Access | Modify | Rec Proc Monitor | PP |
---|---|---|---|---|---|---|---|---|
OUT | Output Specification | OUTLINK | Yes | 0 | Yes | Yes | N/A | No |
OOPT | Output Execute Option | Menu | Yes | 0 | Yes | Yes | No | No |
DOPT | Output Data Option | Menu | Yes | 0 | Yes | Yes | No | No |
OCAL | Output Calculation | STRING[36] | Yes | Null | Yes | Yes | No | No |
OVAL | Output Value | DOUBLE | No | 0 | Yes | Yes | Yes | No |
OEVT | Event To Issue | SHORT | Yes | 0 | Yes | Yes | No | No |
ODLY | Output Execution Delay | FLOAT | Yes | 0 | Yes | Yes | No | No |
IVOV | Invalid Output Action | Menu | Yes | 0 | Yes | Yes | No | No |
IVOA | Invalid Output Value | DOUBLE | Yes | 0 | Yes | Yes | No | No |
OSV | Output string value | STRING[40] | NO | 0 | Yes | Yes | Yes | No |
WAIT | Wait for completion? | Menu | Yes | "NoWait" | Yes | Yes | Yes | No |
The sCalcout record now uses device support to write to the
OUT
link. Soft device supplied with the record is selected with
the .dbd specification
field(DTYP,"Soft Channel")This device support uses the record's
WAIT
field to determine
whether to wait for completion of processing initiated by the OUT
link before causing the record to execute its forward link. The mechanism by
which this waiting for completion is performed requires that the
OUT
link have the attribute CA
-- i.e., the link text
looks something like
xxx:record.field CA NMS
Currently, the record does not try to ensure that WAIT
and
OUT
are compatibly configured. If WAIT
== "Wait",
but the link looks like
xxx:record.field PP NMS
for example, then the record will not wait for completion before executing its forward link.
The EGU field contains a string of up to 16 characters which is supplied by the user and which describes the values being operated upon. The string is retrieved whenever the routine get_units is called. The EGU string is solely for an operator's sake and does not have to be used.
The HOPR and LOPR fields only refer to the limits of the VAL, HIHI, HIGH, LOW, and LOLO fields. PREC controls the precision of the VAL field.
The INAV-INLV and IAAV-ILLV fields indicate the status of the link to the PVs specified in the INPA-INPL and INAA-INLL fields, respectively. The fields can have three possible values:
Ext PV NC | the PV wasn't found on this IOC and a Channel Access link hasn't been established. |
Ext PV OK | the PV wasn't found on this IOC and a Channel Access link has been established. |
Local PV | the PV was found on this IOC. |
Constant | the corresponding link field is a constant. |
The OUTV field indicates the status of the OUT link. It has the same possible values as the INAV-INLV fields.
The CLCV and OLCV fields indicate the validity of the expression in the CALC and OCAL fields, respectively. If the expression is invalid, the field is set to one.
The DLYA field is set to one during the delay interval specified in ODLY.
See the EPICS Record Reference Manual, for more on the record name (NAME) and description (DESC) fields.
Field | Summary | Type | DCT | Initial | Access | Modify | Rec Proc Monitor | PP |
---|---|---|---|---|---|---|---|---|
EGU | Engineering Units | STRING [16] | Yes | Null | Yes | Yes | No | No |
PREC | Display Precision | SHORT | Yes | 0 | Yes | Yes | No | No |
HOPR | High Operating Range | FLOAT | Yes | 0 | Yes | Yes | No | No |
LOPR | Low Operating Range | FLOAT | Yes | 0 | Yes | Yes | No | No |
INAV | Link Status of INPA | Menu | No | 1 | Yes | No | No | No |
INBV | Link Status of INPB | Menu | No | 1 | Yes | No | No | No |
... | ... | ... | ... | ... | ... | ... | ... | ... |
INLV | Link Status of INPL | Menu | No | 1 | Yes | No | No | No |
OUTV | OUT PV Status | Menu | No | 0 | Yes | No | No | No |
CLCV | CALC Valid | LONG | No | 0 | Yes | Yes | No | No |
OCLV | OCAL Valid | LONG | No | 0 | Yes | Yes | No | No |
DLYA | Output Delay Active | USHORT | No | 0 | Yes | No | No | No |
NAME | Record Name | STRING [29] | Yes | 0 | Yes | No | No | No |
DESC | Description | STRING [29] | Yes | Null | Yes | Yes | No | No |
IAAV | Link Status of INAA | Menu | No | 1 | Yes | No | No | No |
IBBV | Link Status of INBB | Menu | No | 1 | Yes | No | No | No |
... | ... | ... | ... | ... | ... | ... | ... | ... |
ILLV | Link Status of INLL | Menu | No | 1 | Yes | No | No | No |
The following alarm parameters which are configured by the user define the limit alarms for the VAL field and the severity corresponding to those conditions.
The HYST field defines an alarm deadband for each limit. See the EPICS Record Reference Manual for a complete explanation of alarms and these fields.
Field | Summary | Type | DCT | Initial | Access | Modify | Rec Proc Monitor | PP |
---|---|---|---|---|---|---|---|---|
HIHI | Hihi Alarm Limit | FLOAT | Yes | 0 | Yes | Yes | No | Yes |
HIGH | High Alarm Limit | FLOAT | Yes | 0 | Yes | Yes | No | Yes |
LOW | Low Alarm Limit | FLOAT | Yes | 0 | Yes | Yes | No | Yes |
LOLO | Lolo Alarm Limit | FLOAT | Yes | 0 | Yes | Yes | No | Yes |
HHSV | Severity for a Hihi Alarm | Menu | Yes | 0 | Yes | Yes | No | Yes |
HSV | Severity for a High Alarm | Menu | Yes | 0 | Yes | Yes | No | Yes |
LSV | Severity for a Low Alarm | Menu | Yes | 0 | Yes | Yes | No | Yes |
LLSV | Severity for a Lolo Alarm | Menu | Yes | 0 | Yes | Yes | No | Yes |
HYST | Alarm Deadband | DOUBLE | Yes | 0 | Yes | Yes | No | No |
Field | Summary | Type | DCT | Initial | Access | Modify | Rec Proc Monitor | PP |
---|---|---|---|---|---|---|---|---|
ADEL | Archive Deadband | DOUBLE | Yes | 0 | Yes | Yes | No | No |
MDEL | Monitor, i.e. value change, Deadband | DOUBLE | Yes | 0 | Yes | Yes | No | No |
The LALM field is used to implement the hysteresis factor for the alarm limits.
The LA-LL fields are used to decide when to trigger monitors for the corresponding fields. For instance, if LA does not equal the value for A, monitors for A are triggered. The MLST and MLST fields are used in the same manner for the VAL field.
Field | Summary | Type | DCT | Initial | Access | Modify | Rec Proc Monitor | PP |
---|---|---|---|---|---|---|---|---|
LALM | Last Alarmed Value | DOUBLE | No | 0 | Yes | No | No | No |
ALST | Archive Last Value | DOUBLE | No | 0 | Yes | No | No | No |
MLST | Monitor Last Value | DOUBLE | No | 0 | Yes | No | No | No |
LA | Previous Input Value for A | DOUBLE | No | 0 | Yes | No | No | No |
LB | Previous Input Value for B | DOUBLE | No | 0 | Yes | No | No | No |
... | ... | ... | ... | ... | ... | ... | ... | ... |
LL | Previous Input Value for A | DOUBLE | No | 0 | Yes | No | No | No |
LAA | Previous Input Value for AA | STRING[40] | No | 0 | Yes | No | No | No |
LBB | Previous Input Value for BB | STRING[40] | No | 0 | Yes | No | No | No |
... | ... | ... | ... | ... | ... | ... | ... | ... |
LLL | Previous Input Value for LL | STRING[40] | No | 0 | Yes | No | No | No |
A routine postfix is called to convert the infix expression in CALC and OCAL to reverse polish notation. The result is stored in RPCL and ORPC, respectively.
upper_alarm_limit = HIHI
upper_warning_limit = HIGH
lower_warning_limit = LOW
lower_alarm_limit = LOLO