Ниже представлен список зарезервированных ключевых слов. Такие идентификаторы не могут быть использованы в качестве имен ПМ или переменных:
A ABS, ACOS, ADD, ANA, AND, AND_MASK, ANDN, ARRAY, ASIN, AT, ATAN,
B BCD_TO_BOOL, BCD_TO_INT, BCD_TO_REAL, BCD_TO_STRING, BCD_TO_TIME, BOO, BOOL, BOOL_TO_BCD, BOOL_TO_INT, BOOL_TO_REAL, BOOL_TO_STRING, BOOL_TO_TIME, BY, BYTE,
C CAL, CALC, CALCN, CALN, CALNC, CASE, CONCAT, CONSTANT, COS,
D DATE, DATE_AND_TIME, DELETE, DINT, DIV, DO, DT, DWORD,
E ELSE, ELSIF, EN, END_CASE, END_FOR, END_FUNCTION, END_IF, END_PROGRAM, END_REPEAT, END_RESSOURCE, END_STRUCT, END_TYPE, END_VAR, END_WHILE, ENO, EQ, EXIT, EXP, EXPT,
F FALSE, FIND, FOR, FUNCTION,
G GE, GFREEZE, GKILL, GRST, GSTART, GSTATUS, GT,
I IF, INSERT, INT, INT_TO_BCD, INT_TO_BOOL, INT_TO_REAL, INT_TO_STRING, INT_TO_TIME,
J JMP, JMPC, JMPCN, JMPN, JMPNC,
L LD, LDN, LE, LEFT, LEN, LIMIT, LINT, LN, LOG, LREAL, LT, LWORD,
M MAX, MID, MIN, MOD, MOVE, MSG, MUL, MUX,
N NE, NOT,
O OF, ON, OPERATE, OR, OR_MASK, ORN,
P PROGRAM,
R R, READ_ONLY, READ_WRITE, REAL, REAL_TO_BCD, REAL_TO_BOOL, REAL_TO_INT, REAL_TO_STRING, REAL_TO_TIME, REPEAT, REPLACE, RESSOURCE, RET, RETAIN, RETC, RETCN, RETN, RETNC, RETURN, RIGHT, ROL, ROR,
S S, SEL, SHL, SHR, SIN, SINT, SQRT, ST, STN, STRING, STRING_TO_BCD, STRING_TO_BOOL, STRING_TO_INT, STRING_TO_REAL, STRING_TO_TIME, STRUCT, SUB, SUB_DATE_DATE, SYS_ERR_READ, SYS_ERR_TEST, SYS_INITALL, SYS_INITANA, SYS_INITBOO, SYS_INITTMR, SYS_RESTALL, SYS_RESTANA, SYS_RESTBOO, SYS_RESTTMR, SYS_SAVALL, SYS_SAVANA, SYS_SAVBOO, SYS_SAVTMR, SYS_TALLOWED, SYS_TCURRENT, SYS_TMAXIMUM, SYS_TOVERFLOW, SYS_TRESET, SYS_TWRITE, SYSTEM,
T TAN, TASK, THEN, TIME, TIME_OF_DAY, TIME_TO_BCD, TIME_TO_BOOL, TIME_TO_INT, TIME_TO_REAL, TIME_TO_STRING, TMR, TO, TOD, TRUE, TYPE,
U UDINT, UINT, ULINT, UNTIL, USINT,
V VAR, VAR_ACCESS, VAR_EXTERNAL, VAR_GLOBAL, VAR_IN_OUT, VAR_INPUT, ,VAR_OUTPUT,
W WHILE, WITH, WORD,
X XOR, XOR_MASK, XORN.
Все ключевые слова, начинающиеся с подчеркивания ('_'), являются внутренними ключевыми словами и не могут быть использованы в текстовых инструкциях.