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PLC Data

DINT Two's Complement: FFFFFFFC = -4

Decode hexadecimal values such as FFFFFFFC (-4) and FFFFFFFF (-1), then distinguish signed DINT, unsigned data, and bit masks before PLC conversion or comparison.

Product
Logix and CIP data types
Level
Intermediate
Read time
9 min
Reviewed
2026-08-07
Author
Toolbox editorial team
Reviewer
Technical review
Public technical overview

What to establish before troubleshooting

A Logix DINT is a signed 32-bit integer with a range of -2,147,483,648 through 2,147,483,647. Other systems may describe the same 32 bits as an unsigned value from 0 through 4,294,967,295.

Signedness changes interpretation, not the stored bits. For example, hexadecimal FFFFFFFC is -4 as a signed 32-bit two's-complement DINT and 4,294,967,292 as an unsigned 32-bit value.

Abbreviated worked example

Why 16#FFFFFFFC equals -4 in a DINT

A device or message returns the 32-bit hexadecimal pattern 16#FFFFFFFC.

  1. 1As an unsigned 32-bit integer, 16#FFFFFFFC equals 4,294,967,292.
  2. 2For signed two's complement, subtract 4,294,967,296 from that unsigned value: 4,294,967,292 - 4,294,967,296 = -4.

Result: The same FFFFFFFC bits represent -4 as a signed DINT or 4,294,967,292 as an unsigned 32-bit value.

Caution: Confirm the producer's data contract before converting; do not mask the sign bit or force a positive display when the source is defined as signed.

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Product
Logix and CIP data types
Level
Intermediate
Sources
3
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