IDEC FC6A Data Types and WindLDR Memory Map Reference
Key Takeaway
Complete reference for IDEC FC6A memory areas in WindLDR — I/O relays, internal relays, data registers, timers, counters, and special function relays.
Quick Answer
The IDEC FC6A organizes memory into discrete areas: I (inputs), Q (outputs), M (internal relays), R (data registers), T (timers), C (counters), D (special data registers), and SP (special relays). Understanding the memory map is essential for efficient programming and Modbus register mapping.
Memory Area Summary
| Area | Type | Range | Description |
|---|---|---|---|
| I | Bit | I0–I317 | Physical input relays |
| Q | Bit | Q0–Q317 | Physical output relays |
| M | Bit | M0–M7FFF | Internal memory relays |
| R | Word (16-bit) | R0–R7FFF | General data registers |
| T | Bit + Word | T0–T1023 | Timer relays and current values |
| C | Bit + Word | C0–C1023 | Counter relays and current values |
| D | Word (16-bit) | D0–D8999 | Special data registers |
| SP | Bit | SP0–SP999 | Special system relays |
Data Types
- INT (16-bit) — Single R register, range -32768 to 32767
- DINT (32-bit) — Two consecutive R registers (e.g., R0+R1)
- REAL (32-bit float) — Two consecutive R registers, IEEE 754 format
- BOOL — Single bit in M, I, Q, T, or C areas
Retentive vs Non-Retentive
By default, M relays and R registers lose their values on power cycle. WindLDR allows configuring ranges of M and R areas as retentive, preserving values through power loss. Configure retentive ranges in Function Area Settings.
Special Relays (SP)
- SP0 — Always ON
- SP1 — Always OFF
- SP2-SP5 — Clock pulse relays (10ms, 100ms, 1s, 1min)
- SP6 — First scan flag
- SP50+ — Error flags (CPU error, I/O error, communication error, battery low)
Frequently Asked Questions
R registers are general-purpose 16-bit data registers. D registers are special function registers for system use, PID parameters, and communication settings.
REAL values occupy two consecutive R registers (e.g., R0 and R1). WindLDR handles the two-register allocation automatically when declaring REAL variables.