DcSysTime

DcSysTime is a type representing a time on the EtherCAT distributed clock (Distributed Clock, DC). It is used with TransitionMode::SysTime, GpioOut::SysTimeEq, and the like.

In EtherCAT, there is a clock synchronized across all slaves (the distributed clock), and each device operates in sync with it. This time is a 64-bit counter in ns units, counted from 2000-01-01 00:00:00 (UTC).

Construction

DcSysTime is constructed from the current time, a UTC datetime, or raw ns.

Rust

let epoch = DcSysTime::ZERO;
let now = DcSysTime::now();
let at = DcSysTime::from_utc(Utc.with_ymd_and_hms(2025, 1, 1, 0, 0, 0).unwrap()).unwrap();
let raw = DcSysTime::from_nanos(1_000_000_000);
let ns: u64 = now.sys_time();
let utc = now.to_utc();

Python

epoch = DcSysTime.ZERO
now = DcSysTime.now()
raw = DcSysTime.from_nanos(1_000_000_000)
ns = now.sys_time

C#

var epoch = DcSysTime.Zero;
var now = DcSysTime.Now();
var at = DcSysTime.FromUtc(new DateTime(2025, 1, 1, 0, 0, 0, DateTimeKind.Utc));
var raw = DcSysTime.FromNanos(1_000_000_000);
ulong ns = now.SysTime;
DateTime utc = now.ToUtc();

Operation	Description
ZERO	Epoch (2000-01-01 00:00:00 UTC)
now()	Current time of the host
from_nanos(ns)	Construct from ns elapsed since the epoch
from_utc(utc)	Construct from a UTC datetime
sys_time()	ns elapsed since the epoch
to_utc()	Convert to a UTC datetime

Note

The Python version does not have from_utc / to_utc.

Arithmetic

DcSysTime defines operations that add and subtract time differences.

Rust

let future = DcSysTime::now() + Duration::from_millis(100);
let past = future - Duration::from_millis(50);
let elapsed: Duration = future - past;
let is_after: bool = future > past; // true

Python

future = DcSysTime.now() + Duration.from_millis(100)
past = future - Duration.from_millis(50)

C#

var future = DcSysTime.Now() + TimeSpan.FromMilliseconds(100);
var past = future - TimeSpan.FromMilliseconds(50);
bool isAfter = future > past; // true

Operation	Result	Description
DcSysTime + Duration	DcSysTime	Add the specified duration
DcSysTime - Duration	DcSysTime	Subtract the specified duration
DcSysTime - DcSysTime	Duration	Difference between two times (Rust only)
Comparison (< / > / ==, etc.)	bool	Comparison (Rust / C# only)

Rust uses core::time::Duration for Duration, C# uses TimeSpan, and Python uses autd3.Duration. Python provides only addition and subtraction (applying a time difference via + / -); it does not have computing a time difference or comparison.