Allen-Bradley LOGIX 5000 User Manual

Chapter 11
Common Attributes for Advanced Process Control and Drives Instructions
546 Rockwell Automation Publication 1756-RM006K-EN-P - November 2018
The REAL data type also stores infinity and NAN, but the software
display differs based on the display format.
Data type conversions
When data types are mixed for operands within an instruction, some instructions
automatically convert data to an optimal data type for that instruction. In some
cases, the controller converts data to fit a new data type; in some cases the
controller just fits the data as best it can.
Conversion Result
larger integer to smaller integer The controller truncates the upper portion of the larger integer and
generates an overflow.
For example:
Decimal Binary
DINT 65,665 0000_0000_0000_0001_0000_0
000_1000_0001
INT 129 0000_0000_1000_0001
SINT -127 1000_0001
SINT or INT to REAL No data precision is lost
DINT to REAL Data precision could be lost. Both data types store data in 32 bits, but the
REAL type uses some of its 32 bits to store the exponent value. If precision is
lost, the controller takes it from the least-significant portion of the DINT.
LREAL to LREAL No data precision is lost.
LREAL TO REAL Data precision could be lost.
LREAL/REAL to unsigned integer Data precision could be lost. If the source value is too big to fit into
destination the controller stores what it can and may produce an overflow.
Signed Integer/Unsigned Integer to
LREAL/REAL
If the integer value has more significant bits than can be stored in the
destination, the lower bits will be truncated.
Signed integer to unsigned integer If the source value is too big to fit into destination the controller stores what
it can and may produce an overflow.
Unsigned integer to signed integer If the source value is too big to fit into destination the controller stores what
it can and may produce an overflow.
REAL to integer The controller rounds the fractional part and truncates the upper portion of
the non-fractional part. If data is lost, the controller sets the overflow status
flag.
Rounding is to the nearest whole number:
less than 0.5, round down; equal to 0.5, round to nearest even integer;
greater than 0.5, round up
For example:
REAL (source) DINT (result)

Allen-Bradley LOGIX 5000 Specifications

General

Brand	Allen-Bradley
Model	LOGIX 5000
Category	Controller
Language	English