Scripts are divided into two parts: Declaration Part and Program Part. The declaration part is for the declaration of internal variables and input parameters. The program part includes all program statements except for the variable declarations.
Comments can be entered anywhere in the program. Strings starting with ‘//’ are treated as comments until the end of the line.
(1) Declaration Part
Item | Description |
Variable Declaration | Declare internal variables using the following format: VAR variable_name; The initial value of declared variables is 0. To declare more than one variable, use a comma “ , ” between variables: VAR variable_name_1, variable_name_2, … , variable_name_n; You can use multiple VAR keywords before the program part starts. Variable names cannot share the same names as tag names (Group, Digital, Analog, or String tags). Duplicate names may cause compiler errors or incorrect operation. |
Input Parameter Declaration | Declare input parameters using the following format: PARAM 1st parameter [, 2nd parameter …]; Input parameters are used when a program is called by another program or command. The declaration order must be identical to the order of input parameters. The parameters will be initialized with the values assigned by the caller. To declare more than one parameter, use a comma “ , ” between them. You can use several PARAM keywords before the program part starts. |
Example | //Program Name: MyPgm VAR a, b; VAR c; PARAM p1, p2; PARAM p3;
The program MyPgm can be called by the external caller as shown below: MyPgm(1,2,3); The values (1, 2, and 3) will be stored in the parameters p1, p2, and p3, respectively. The variables a, b, and c, will be initialized as 0. |
(2) Program part
In the program part, all program statements except the declaration (variables and parameters) can be used. An example of the most basic statement is the function call, calculation, and storing the result.
The following program example is composed of basic statements.
Tag_a = Tag_a + 1;
Tag_b = MyPgm(Tag_a, 2, 3);
Each statement must end with a semicolon “ ; ”. Each function returns a single result to the caller. The program shown above returns the result of MyPgm to “Tag_b”.
(3) Constants
When you use constants in the program, you can use the notations as shown below.
Item | Description |
Octal Constants | Base 8; digits only range from 0 to 7. Octal constants must start with 0. (E.g. 01277) |
Decimal Constants | The general notation is used. (E.g. 153, 3.14, 2.45E-12) |
Hexadecimal Constants | Base 16. Must start with ‘0x’. Use the alphabet or number characters between ‘0’ and ‘F’. (E.g. 0xFFFF) |
String Constants | Strings must be between two double-quotation marks (“ ”). (E.g. “String Variable1”) |
You can also utilize the predefined constants as shown below.
Constant Name | Value | Usage |
_PI_ | 3.141592… | 3.141592… (Value of π) |
_LOCAL_ | 0 | Local Flash Memory |
_SDMEM_ | 1 | SD/MMC Memory |
_USBMEM_ | 2 | USB Memory |
_COM232_ | 0 | Uses COM1 port as RS232C mode. |
_COM422_ | 1 | Uses COM1 port as RS422 mode. |
_COM485_ | 2 | Uses COM1 port as RS485 mode. |
_COMAUX_ | 3 | Uses COM2 port as RS232C mode only. |
_BPS300_ |
| 300 bps |
_BPS600_ |
| 600bps |
_BPS1200_ |
| 1200bps |
_BPS2400_ |
| 2400bps |
_BPS4800_ |
| 4800bps |
_BPS9600_ |
| 9600bps |
_BPS19200_ |
| 19200bps |
_BPS38400_ |
| 38400bps |
_BPS56000_ |
| 56000bps |
_BPS57600_ |
| 57600bps |
_BPS115200_ |
| 115200bps |
_BPS128000_ |
| 128000bps |
_BPS256000_ |
| 256000bps |
_PARITY_NONE_ |
| No parity |
_PARITY_EVEN_ |
| Even parity |
_PARITY_ODD_ |
| Odd parity |
_PARITY_MARK_ |
| Mark parity |
_PARITY_SPACE_ |
| Space parity |
_STOPBIT_ONE_ |
| 1 stop bit |
_STOPBIT_TWO_ |
| 2 stop bits |
_STOPBIT_ONE5_ |
| 1.5 stop bit |
_ALMPRT_ALL_ |
| Prints all items of alarm data. |
_ALMPRT_TIME_ |
| Prints the time of alarm data. |
_ALMPRT_ADDR_ |
| Prints the address of the alarm point. |
_ALMPRT_VALUE_ |
| Prints the value of the alarm. |
_ALMPRT_TYPE_ |
| Prints the alarm type. |
_ALMPRT_DESC_ |
| Prints the alarm description. |
_UINT_ |
| Unsinged integer |
_INT_ |
| Singed integer |
_FLOAT_ |
| Floating point value |
_HEX_ |
| Hexa-decimal number |
_EXP_ |
| Real number with an exponent |