PLC Data Types & Ranges
Check a value
Ranges follow the bit width defined by IEC 61131-3. DATE and DATE_AND_TIME sizes depend on the platform; check your PLC manual. REAL holds ~7 significant digits: 16 777 217 is stored as 16 777 216.
IEC 61131-3 elementary types
| Type | Bits | Range | Literal |
|---|---|---|---|
BOOL Bit string | 1 | 0 … 1 | TRUE |
BYTE | 8 | 0 … 255 | 16#FF |
WORD | 16 | 0 … 65535 | 16#FFFF |
DWORD | 32 | 0 … 4294967295 | 16#FFFF_FFFF |
LWORD | 64 | 0 … 18446744073709551615 | 16#FFFF_FFFF_FFFF_FFFF |
SINT Signed integer | 8 | -128 … 127 | -128 |
INT | 16 | -32768 … 32767 | -32768 |
DINT | 32 | -2147483648 … 2147483647 | -2147483648 |
LINT | 64 | -9223372036854775808 … 9223372036854775807 | -9223372036854775808 |
USINT Unsigned integer | 8 | 0 … 255 | 255 |
UINT | 16 | 0 … 65535 | 65535 |
UDINT | 32 | 0 … 4294967295 | 4294967295 |
ULINT | 64 | 0 … 18446744073709551615 | 18446744073709551615 |
REAL Floating point | 32 | ±1.175494e−38 … ±3.402823e+38, ~7 significant digits | 1.0E-3 |
LREAL | 64 | ±2.225074e−308 … ±1.797693e+308, ~15–16 significant digits | 1.0E-3 |
TIME Duration | 32 | T#-24d20h31m23s648ms … T#24d20h31m23s647ms (ms) | T#1h30m |
LTIME | 64 | LT#-106751d23h47m16s854ms775us808ns … LT#106751d23h47m16s854ms775us807ns (ns) | LT#1s500us |
DATE Date and time | 16 | Siemens S7: D#1990-01-01 … D#2168-12-31 (days since 1990-01-01); size is platform-specific | D#2026-10-02 |
TIME_OF_DAY | 32 | TOD#00:00:00.000 … TOD#23:59:59.999 (ms since midnight) | TOD#08:30:00 |
DATE_AND_TIME | 64 | Siemens S7: DT#1990-01-01-00:00:00 … DT#2089-12-31-23:59:59.999 (BCD); size is platform-specific | DT#2026-10-02-08:30:00 |
CHAR Character | 8 | single-byte character | 'A' |
WCHAR | 16 | UCS-2 character | "Ж" |