12345678
&H3EF =1007 (decimal)

If the result of an expression is outside the 32-bit limits, it will overflow and change sign. Care must therefore be exercised to prevent unexpected result from an integer-overflow condition.

A constant may be used in an assignment statement or in an expression as follow:

A = 12345
IF A*30 + 2345/123 > 100
THEN ....ENDIF

IMPORTANT (16-bit variables comparison)

When entering an integer constant using the hexadecimal prefix "&H", it is important to note the sign of the intended value and extend the signs to most significant bit of the 32 bit expression. E.g. to represent a decimal number "-1234", the hexadecimal representation must be "&HFFFFFB2E" and not "&HFB2E". Assuming that a 16-bit variable DM[1] contains the number -1234 and a comparison statement is made to check if the number is -1234. The 32-bit hexadecimal representation of constant -1234 is &HFFFFFB2E. If you enter the constant as 16-bit representation "&HFB2E" as follow: IF DM[1] <> &HFB2E CALL 5 TBASIC translates the number "&HFB2E" into a 32-bit decimal number 64302, which when compared to the number "-1234" contained in DM[1] will yield a "False" result which is an error. The following are the correct representation: a) IF DM[1] <> -1234 CALL 5 : ENDIF b) IF DM[1] <> &HFFFFFB2E" CALL 5: ENDIF

2.     Integer variables:

Variables are memory locations used for storing data for later use. All Integer variables used in TBASIC are GLOBAL variables - this means that all these variables are shared and accessible from every custom function.

NEW! With i-TRiLOGI version 6.2 and above, you can now attach comments to any variable name of any length to make program easier to read. See section 5 (Integer Variable Comments) below for more details. Specific examples with each variable type are shown below.

1. 26 Integer variables A, B, C....Z which are 32-bit variables. Note that the variable name is a single character by default; however, as mentioned above, you can append a comment to the variable. EG:  A_temperature, A_distance - both refer to the same variable A

2. A large, one-dimensional 16-bit integer array from DM[1] to DM[4000], where DM stands for Data Memory. A DM is addressed by its index enclosed between the two square brackets "[" and "]". e.g. DM[3], DM[A+B*5], where A and B are integer variables. A comment can also be appended to DM[] variables as follows: DM[1]_Current_status_of _product1 - refers to variable DM[1].

3. Starting from version 6.45, the DM[1] to DM[4000] can also be used as 32-bit variables DM32[1] to DM32[2000] in the following manner:  DM[1] & DM[2] == DM32[1],  DM[3] & DM[4]==DM32[2]... DM[2N-1] & DM[2N] = DM32[N].  If you require lots of 32 bit variables it may be simpler to use only the DM32 and not the 16-bit DM. If you mix the use of both DM and DM32 then you need to manage the memory properly to ensure that they don't overwrite each other memory space.
   
   The simulator fully support the use of DM32 variables in any expression. However, for the actual PLC only those with firmware r78 supports DM32 variables. PLC with older firmware cannot directly use DM32 in the program.
   
      E.g.   DM32[100] = DM[1] * A

4. System variables. These are special integer variables that relate to the PLC hardware, which will be described in the next section.

3.     System variables:

NOTE: All of the following System Variables can have comments appended to them with the same format as described in section 5 (Integer Variable Comments).

Inputs, Outputs, Relays, Timers and Counters Contacts

The bit addressable I/Os elements are organized into 16-bit integer variables INPUT[n], OUTPUT[n], RELAY[n], TIMERBIT[n] and CTRBIT[n] so that they may be easily accessed from within a CusFn. These I/Os are arranged as shown in the following diagram:

timerPV[1] to timerPV[256], for timers' present value

ctrPV[1] to ctrPV[256], for counters' present value

DATE and TIME Variables

The PLC's Real-Time-Clock (RTC) derived date and time can be accessed via variables DATE[1] to DATE[3] and TIME[1] to TIME[3], respectively as shown in the following table:

Date		Time
YEAR	DATE[1]	HOUR	TIME[1]
MONTH	DATE[2]	MINUTES	TIME[2]
DAY	DATE[3]	SECOND	TIME[3]
Day of Week	DATE[4]

DATE[1] : may contain four digits (e.g. 1998, 2003 etc).
DATE[4] : 1 for Monday, 2 for Tuesday, .... 7 for Sunday.

High Speed Counters

The M-series and F-Series PLCs support High Speed Counters (HSC), which can be used to capture high frequency incoming pulses from positional feedback encoder. These high speed counters are accessible by CusFn using the variables HSCPV[1] to HSCPV[8]. All HSCPV[n] are 32-bit integer variables.

Special Variables - Used by EMIT.

4 x  special 16 bit integer variables:  EMEVENT[1] to EMEVENT[4] - emEvent[1] is also used for email purpose.

16 x  16-bit integer variables:  EMINT[1] to EMINT[16]

16 x  32-bit integer variables:  EMLINT[1] to EMLINT[16]

4.     Integer operators:

"Operators" perform mathematical or logical operations on data. TBASIC supports the following integer operators:

i) Assignment Operator: An integer variable (A to Z, DM and system variables, etc) may be assigned a value using the assignment statement:

A = 1000
X = H*I+J + len(A$)

ii) Arithmetic Operators:

Symbol	Operation	Example
+	Addition	A = B+C+25
-	Subtraction	Z = TIME[3]-10
*	Multiplication	PRINT #1 X*Y
/	Division	X = A/(100+B)
MOD	Modulus	Y = Y MOD 10

iii) Bitwise Logical Operators: logical operations is perform bit-for-bit between two 16-bit integer data.

Symbol	Operation	Example
&	logical AND	IF input[1] & &H02 ...
|	logical OR	output[1] = A | &H08
^	Exclusive OR	A = RELAY[2] ^ B
~	logical NOT	A = ~timerPV[1]

iv) Relational Operators : Used exclusively for decision making expression in statement such as IF expression THEN ..... and WHILE expression ....

Symbol	Operation	Example
=	Equal To	IF A = 100
<>	Not Equal To	WHILE CTR_PV[0]<> 0
>	Greater Than	IF B > C/(D+10)
<	Less Than	IF TIME[3] < 59
>=	Greater Than or Equal To	WHILE X >= 10
<=	Less Than or Equal To	IF DM[I] <= 5678
AND	Relational AND	IF A>B AND C<=D
OR	Relational OR	IF A<>0 OR B=1000

v) Functional Operators : TBASIC supports a number of built in functions which operate on integer parameters as shown below:

ABS(n), ADC(n), CHR$(n), HEX$(n), STR$(n)

For detailed explanation of these functions please refer to the next chapter: "Programming Language Reference"

5.     Hierarchy of Operators

The hierarchy of operators represent the priority of computation. Eg. X = 3 + 40*(5 - 2). The compiler will generate codes to compute 5 - 2 first because the parentheses has the higher hierarchy, the result is then multiplied by 40 because multiplication has a higher priority then addition. Finally 3 will be added to the result. If two operators are of the same hierarchy, then compiler will evaluate from left to right. e.g. X = 5 + 4 - 3. 5+4 is first computed and then 3 will be subtracted. The following table list the hierarchy of various operator used.

Hierarchy	Symbol	Descriptions
Highest	( )	Parentheses
	*, / , MOD	Multiplication/Division
	+, -	Add/Subtract
	-	Negate
	&, |, ^,~	Logical AND,OR,XOR,NOT
Lowest	=,<>,>,>=,<,<=	Relational operators

6.     Integer Variable Comments

With i-TRiLOGI version 6.2 and above, you can now attach comments to any variable/register name of any length to make program easier to read. The compiler will ignore any alphanumeric characters (A to z, 0 to 9 and ‘_’) that are attached behind the variable name following an underscore character “_”. It is important to understand that by appending these comments to variables, no new variables are being created.

For Example: "X_Some_Integer" corresponds to "X"

An integer variable (such as DM[1]) can have different comments each time it is referenced in the same program because the compiler ignores the comments anyways. Although, in most cases it may be best to limit a variable to one comment to avoid potentially overwriting data since no new variables are actually create, as mentioned above.

For Example: If an integer variable, DM[1], was named "DM[1]_one_integer" in one part of a program and named "DM[1]_two_integer" in another part of the program, then they will still both refer to DM[1]. If each variation has different integer data, then the data that was stored in the last variation that was updated will be the data in DM[1]. Then if the previous variation is accessed, it wont contain the data that was originally stored in it.

7.     Variable Define Table (NEW!)

With TRiLOGI version 6.42 and higher, it is possible to create a table of variable/constant/expression definitions. Please see section "8. Define" in the Introduction to TBASIC & Custom Functions for more information on how to interface to the Define Table. Here is an example of a possible Define Table :

The following explanations will reference the above example define table.

Creating Variable Definitions

It is possible to define label names for any variable available in TRiLOGI. The following results will happen based associated program code :

Creating Constant Definitions

It is possible to define label names for constant values. The following results will happen based associated program code :

Creating Expression Definitions

It is possible to define label names for entire expressions or code snippets. The following results will happen based associated program code :

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