S5 Timer Time Base Reference: KT Format Explained
Complete reference for the S5 KT timer format. Time base values 0–3, resolution, maximum duration, BCD encoding, and conversion formulas.
S5 Timer Time Base Reference: KT Format Explained
The S5 timer value format KT uses a BCD-encoded value with a time base selector. The format is KT value.timebase where value is 000–999 (BCD) and timebase is 0–3.
Time Base Table
| Time Base | Resolution | Multiplier | Max Value (999×) | Typical Use |
|---|---|---|---|---|
| 0 | 10 ms | 0.01 s | 9.99 s | Fast signals, debouncing |
| 1 | 100 ms | 0.1 s | 99.9 s | Standard delays |
| 2 | 1 s | 1.0 s | 999 s (16.65 min) | Process timers |
| 3 | 10 s | 10.0 s | 9990 s (2.78 h) | Long delays, shift timers |
Conversion Formula
Duration (seconds) = value × multiplier
Common KT Values
| KT Value | Calculation | Duration | IEC Format |
|---|---|---|---|
| KT 001.0 | 1 × 10ms | 10 ms | T#10ms |
| KT 010.0 | 10 × 10ms | 100 ms | T#100ms |
| KT 100.0 | 100 × 10ms | 1 s | T#1s |
| KT 010.1 | 10 × 100ms | 1 s | T#1s |
| KT 001.2 | 1 × 1s | 1 s | T#1s |
| KT 015.1 | 15 × 100ms | 1.5 s | T#1s500ms |
| KT 020.1 | 20 × 100ms | 2 s | T#2s |
| KT 030.1 | 30 × 100ms | 3 s | T#3s |
| KT 050.1 | 50 × 100ms | 5 s | T#5s |
| KT 100.1 | 100 × 100ms | 10 s | T#10s |
| KT 010.2 | 10 × 1s | 10 s | T#10s |
| KT 030.2 | 30 × 1s | 30 s | T#30s |
| KT 060.2 | 60 × 1s | 60 s | T#1m |
| KT 300.2 | 300 × 1s | 300 s | T#5m |
| KT 030.3 | 30 × 10s | 300 s | T#5m |
| KT 060.3 | 60 × 10s | 600 s | T#10m |
| KT 180.3 | 180 × 10s | 1800 s | T#30m |
| KT 360.3 | 360 × 10s | 3600 s | T#1h |
| KT 999.3 | 999 × 10s | 9990 s | T#2h46m30s |
BCD Encoding in Memory
The KT value is stored as a 16-bit word in BCD format:
Bit: 15 14 | 13 12 | 11 8 | 7 4 | 3 0
x x | TB TB | BCD | BCD | BCD
timebase hundreds tens ones
- Bits 15–14: Unused (always 0)
- Bits 13–12: Time base (0–3)
- Bits 11–0: BCD value (3 BCD digits, 000–999)
Example: KT 543.2
- Time base 2 → bits 13-12 =
10 - Value 543 → BCD =
0101 0100 0011 - Full word:
00 10 0101 0100 0011= hex0x2543
Accuracy Warning
S5 timers are not high-precision. The actual resolution depends on the CPU scan cycle:
- A timer with 10ms resolution on a CPU with 50ms scan time effectively has 50ms resolution
- Timer accuracy is ±1 scan cycle in the worst case
For the complete timer conversion guide, see S5 Timer Conversion.
Use our free S5 Timer Calculator to convert any KT value instantly.
Part of the S5→S7 Timer Reference. Maintained by PLCcheck.ai.
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