TwinCAT3 使用入门: 变量命名规则建议

常量

常量都用大写字母来表示，用下划线 “_” 加强可读性。
VAR CONSTANT

         STEP_CONDITIONING: USINT := 23; (* [-] *)
         HEATING_TIME_OUT: UINT := 5000; (* [s] *)
         MAX_PRESSURE: REAL := 6.7e+006; (* [Pa]*)

END_VAR

Definition of object names

Object	Prefix	Description	Example
FUNCTION_BLOCK	FB_	Function Block	FB_GetData
STRUCT	ST_	Structure	ST_BufferEntry
ENUM	E_	Type of Enumeration	E_SignalStates
TYPE	T_	Reference	T_Nibble
PROGRAM	P_	Program	P_Axis
FUNCTION	F_	Function	F_Convert

Generating instances of objects

Object	Prefix	Description	Instance	Call example
function block	fb	Instance name from function block	fbGetData	fbGetData();
struct	st	Instance name of the structure	stBufferEntry	stBufferEntry.nCounter := 5;
enum	e	Enum instance	eSignalState	eSignalState := E_STOP;
alias type	none	Instance name of a reference type	Nibble	Nibble := 1;

Generating instances of variables

Type	Prefix	Description	Example
SINT, USINT, …, DINT, UDINT, BYTE, WORD, DWORD, LWORD....	n, i	numeric / integer	nCount, iError
BOOL	b	bit	bSwitch
REAL, LREAL	f	float	fValue
STRING	s	string	sName
TIME	t	time	tDelay
DATE	d	date	dMonday
DATE_AND_TIME	dt	date and time	dtNewYear
ARRAY[...] OF ...	arr	arrays	arrMessages
p	p	pointer	pData

Other prefixes that may also be used

Prefix	Description	Example
cb	count of bytes	cbLength
cw	count of words	cwRead

硬件链接变量

Prefix	Type
di	Digital input
do	Digital Output
ai	Analog input
ao	Analog output

文件标题

每个文件必须包含一个标题，它包括:
• 作者和版权信息
• 简单介绍（摘要注释），重点是程序目标，输入输出变量，程序运行的结果，限制和接口设定
• 定时动作和内存要求（临界状态）
• 版本号，历史和数据

空格

为了增加可读性，在每个操作符的前后都加上一个空格:
xAxisPos = x0 + deltaX;
if (machineState == STATE_RUN)

最后修改: 2019年08月1日星期四 10:42