DINT

**DINT (Double Integer) is a 32-bit signed integer** with values from −2,147,483,648 to +2,147,483,647. The IEC 61131-3 standard 32-bit signed integer and the default for most modern PLC counter and timer applications. On Allen-Bradley/Studio 5000, DINT is the default integer type for new tags.

**Range:** −2,147,483,648 (−2³¹) to +2,147,483,647 (2³¹ − 1).

**Memory:** exactly 4 bytes (32 bits).

**Common uses:** - High-resolution counter accumulators - Encoder position counts (32-bit encoders are common) - Timer accumulators in milliseconds (max ~24 days vs INT's max 32 seconds) - File sizes, byte counts in network messages - Currency values in cents (avoiding floating-point precision issues) - Recipe IDs and large enumerations

**Syntax across major IDEs:** - Studio 5000 ST: `myCount : DINT := 0;` (Allen-Bradley's default integer type) - Siemens SCL: `myCount : DINT := 0;` - CODESYS / TwinCAT: `myCount : DINT := 0;` - Mitsubishi GX Works3: `KD` prefix for 32-bit signed decimal literals

**Why prefer DINT over INT:** the memory cost is negligible on modern PLCs (4 bytes vs 2), and you eliminate an entire class of overflow bugs. On Allen-Bradley platforms, DINT is the default — there's no good reason to use INT unless you're communicating with a legacy device that forces a 16-bit register.

**Common pitfalls:** overflow at +2,147,483,647 + 1 wraps to −2,147,483,648 silently; converting DINT to INT truncates the upper 16 bits without warning on most IDEs; floating-point conversion through REAL loses precision above 2²⁴ (16,777,216).

**Conversion:** `DINT_TO_REAL()` (lossless up to 2²⁴), `DINT_TO_LREAL()` (lossless), `INT_TO_DINT()` (sign-extends).

**See also:** INT (signed 16-bit), DWORD (unsigned 32-bit), UDINT (explicitly unsigned 32-bit), LINT (signed 64-bit), REAL (32-bit floating point).