UTC-Time LWORD format specification
The TwinCAT UTC-Time components are coded in LWORD in the following way:
Bit | Component | Type | Value range | Description |
|---|---|---|---|---|
0..31 | secondSinceEpoch | DT | 0..16#FFFFFFFF | Number of whole seconds since January 1, 1970. |
32..55 | fractionOfSecond | 0..16#FFFFFF | Seconds fraction encoded as 24-bit number. | |
56 | Quality.LeapSecondsKnown | BIT | 0..1 | Quality of the leap second (0:=unknown, 1:=known). |
57 | Quality.ClockFailure | BIT | 0..1 | Quality of the timer (0:=good, 1:=erroneous). |
58 | Quality.ClockNotSynchronized | BIT | 0..1 | Quality of the time synchronization (0:=synchronized, 1:=not synchronized). |
59 | Quality.Accuracy0 | BIT | 0..1 | Accuracy of the time information (precision of the fraction of a second). The accuracy bits determine the number of significant bits of the T_UtcTime.fractionOfSecond component. |
60 | Quality.Accuracy1 | BIT | 0..1 | |
61 | Quality.Accuracy2 | BIT | 0..1 | |
62 | Quality.Accuracy3 | BIT | 0..1 | |
63 | Quality.Accuracy4 | BIT | 0..1 |
The UTC-Time.fractionOfSecond component is coded in the 24 bits of the type T_UINT24 in the following way:
Bit | Component | Value |
|---|---|---|
0 | fractionOfSecond[0].0 | 0.5 s |
1 | fractionOfSecond[0].1 | 0.25 s |
2 | fractionOfSecond[0].2 | 0.125 s |
3 | fractionOfSecond[0].3 | 0.0625 s |
4 | fractionOfSecond[0].4 | 0.03125 s |
5 | fractionOfSecond[0].5 | 0.015625 s |
6 | fractionOfSecond[0].6 | 0.0078125 s |
7 | fractionOfSecond[0].7 | 0.00390625 s |
8 | fractionOfSecond[1].0 | 0.001953125 s |
9..15 | fractionOfSecond[1].1..7 | etc. |
16..23 | fractionOfSecond[2].0..7 | -/- |
Samples
The table below contains some fraction-of-a-second values and the values of the fractionOfSecond array elements after the conversion.
Fraction of a second | T_UINT24 | Description |
|---|---|---|
0 s | [0,0,0] | All bits have the value: 0. |
0.75 s | [3,0,0] | Bits 0 and 1 are set. Value calculation: 0.5 s + 0.25 s = 0.75 s. |
0.875 s | [7,0,0] | Bits 0, 1 and 2 are set. Value calculation: 0.5 s + 0.25 s + 0.125 s = 0.875 s. |
0.5625 s | [9,0,0] | Bits 0 and 3 are set. Value calculation: 0.5 s + 0.0625 s = 0.5625 s. |
Coding of the precision in the UTC-Time.Quality.Accuracy0..4 bits.
Precision | Accuracy0 | Accuracy1 | Accuracy2 | Accuracy3 | Accuracy4 | E_UtcTimeAccuracy |
|---|---|---|---|---|---|---|
0-bit | 0 | 0 | 0 | 0 | 0 | Zero |
1-bit | 0 | 0 | 0 | 0 | 1 | _01 |
2-bit | 0 | 0 | 0 | 1 | 0 | _02 |
3-bit | 0 | 0 | 0 | 1 | 1 | _03 |
4-bit | 0 | 0 | 1 | 0 | 0 | _04 |
5-bit | 0 | 0 | 1 | 0 | 1 | _05 |
6-bit | 0 | 0 | 1 | 1 | 0 | _06 |
7-bit | 0 | 0 | 1 | 1 | 1 | _07 |
8-bit | 0 | 1 | 0 | 0 | 0 | _08 |
9-bit | 0 | 1 | 0 | 0 | 1 | _09 |
10-bit | 0 | 1 | 0 | 1 | 0 | _10 |
11-bit | 0 | 1 | 0 | 1 | 1 | _11 |
12-bit | 0 | 1 | 1 | 0 | 0 | _12 |
13-bit | 0 | 1 | 1 | 0 | 1 | _13 |
14-bit | 0 | 1 | 1 | 1 | 0 | _14 |
15-bit | 0 | 1 | 1 | 1 | 1 | _15 |
16-bit | 1 | 0 | 0 | 0 | 0 | _16 |
17-bit | 1 | 0 | 0 | 0 | 1 | _17 |
18-bit | 1 | 0 | 0 | 1 | 0 | _18 |
19-bit | 1 | 0 | 0 | 1 | 1 | _19 |
20-bit | 1 | 0 | 1 | 0 | 0 | _20 |
21-bit | 1 | 0 | 1 | 0 | 1 | _21 |
22-bit | 1 | 0 | 1 | 1 | 0 | _22 |
23-bit | 1 | 0 | 1 | 1 | 1 | _23 |
24-bit | 1 | 1 | 0 | 0 | 0 | _24 |
Impermissible | 1 | 1 | n | n | n | _25_invalid.._30_invalid |
Not specified | 1 | 1 | 1 | 1 | 1 | Unspecified |
Samples
The table below contains some LWORD values and the values after conversion to a formatted Binary-Time string and the structured type: T_UtcTime.
LWORD | STRING(39) | T_UtcTime | Description |
|---|---|---|---|
16#0000000000000000 | 'UT#1970-01-01-00:00:00.000000000|000|0' | STRUCT(0) | All components have the value 0. Date: January 1, 1970. Time: 00:00:00. Fraction of a second: 0 ms. Precision: 0 bit. |
16#C4000000386D4380 | 'UT#2000-01-01-00:00:00.000000000|001|3' | STRUCT(secondSinceEpoch:=DT#2000-01-01-00:00:00, fractionOfSecond:=[0,0,0], quality:=(ClockNotSynchronized:=1, Accuracy3:=1, Accuracy4:=1)) | Date: January 1, 2000. Time: 00:00:00. Fraction of a second: 0 ms. Timer is not synchronized. Precision: 3-bit. |
16#A4000001386D4380 | 'UT#2000-01-01-00:00:00.500000000|001|5' | STRUCT(secondSinceEpoch:=DT#2000-01-01-00:00:00, fractionOfSecond:=[1,0,0], quality:=(ClockNotSynchronized:=1, Accuracy2:=1, Accuracy4:=1)) | Date: January 1, 2000. Time: 00:00:00. Fraction of a second: 500 ms. Timer is not synchronized. Precision: 5-bit. |
16#81000000FFFFFFFF | 'UT#2106-02-07-06:28:15.000000000|100|1' | STRUCT(secondSinceEpoch:=DT#2106-02-07-06:28:15, fractionOfSecond:=[0,0,0], quality:=(LeapSecondsKnown:=1, Accuracy4:=1)) | Date: February 7, 2106. Time: 06:28:15. Fraction of a second: 0 ms. Leap seconds are unknown. Precision: 1-bit. |
16#C2000007FFFFFFFF | 'UT#2106-02-07-06:28:15.875000000|010|3' | STRUCT(secondSinceEpoch:=DT#2106-02-07-06:28:15, fractionOfSecond:=[7,0,0], quality:=(ClockFailure:=1, Accuracy3:=1, Accuracy4:=1)) | Date: February 7, 2106. Time: 06:28:15. Fraction of a second: 875 ms. Timer signals an error. Precision: 3-bit. |
16#1C000007FFFFFFFF | 'UT#2106-02-07-06:28:15.875000000|001|24' | STRUCT(secondSinceEpoch:=DT#2106-02-07-06:28:15, fractionOfSecond:=[7,0,0], quality:=(ClockNotSynchronized:=1, Accuracy0:=1, Accuracy1:=1)) | Date: February 7, 2106. Time: 06:28:15. Fraction of a second: 875 ms. Timer is not synchronized. Precision: 24-bit. |