LREAL data type and syntax
- Last UpdatedJul 29, 2024
- 1 minute read
S7-1500 PLCs contain a data type named LREAL. The LREAL data type is a ANSI/IEEE 754-1985 64-Bit Floating Point value with a range illustrated in the following table:
|
Data Type |
Bit Size |
Range |
|
LREAL |
64 |
-1.7976931348623158e+308 to -2.2250738585072014e-308, ±0, +2.2250738585072014e-308 to +1.7976931348623158e+308 |
S7-1500 PLCs may not support LREAL types on all memory regions.
The item name syntax for LREAL is as follows:
|
Memory Type |
Syntax |
|
Data Block |
D<B,I>d,LREALm D<B,I>d,LREALm,v |
|
Flag Bytes |
FLREALm MLREALm FLREALm,v MLREALm,v |
|
Input Bytes |
ILREALm ELREALm ILREALm,v ELREALm,v |
|
Output Bytes |
OLREALm ALREALm QLREALm OLREALm,v ALREALm,v QLREALm,v |
|
Peripheral Input Bytes |
PILREALm PELREALm PILREALm,v PELREALm,v |
|
Peripheral Output Bytes |
POLREALm PALREALm PQLREALm POLREALm,v PALREALm,v PQLREALm,v |
Where:
|
d |
is the data block number, with a range from 1 to 65535 |
|
m |
is the start offset of an LREAL tag |
|
v |
is the length of an array in elements, with a range from 1 to 65535 |