Time synchronization

This section describes time synchronization capability of HIL Device.

IRIG-B

IRIG-B is a serial data time format consisting of a 1-second frame that contains 100 pulses divided into fields. The time-synchronized device decodes the second, minute, hour and day fields and sets its internal time clock upon detecting the valid time data in the IRIG time mode.

The HIL Device supports the unmodulated IRIG-B input. The unmodulated IRIG-B time-code is IRIG-B00x. The last digit, either 2 or 0, indicates the coded expression(s).

The time-code format IRIG-B002 is a binary-coded decimal (BCD) timecode (HH, MM, SS, DDD). This format represents the traditional, or legacy IRIG-B.

The time-code format IRIG-B000 consists of a BCD timecode (HH, MM, SS, DDD), plus straight binary seconds (SBS) of the day (0-86400 s), and also contains control function extensions that include data for: year, leap seconds, daylight time, UTC time offset, time quality and parity (odd).

When using the IRIG-B000 time-code format, the HIL Device will only parse timecode data.

Time synchronization can be achieved with the precision of a 100th of millisecond. This means that the HIL Device will decode the tens of seconds, second, minute, hour and day fields and will set the internal time clock upon detecting the valid time data in the IRIG time mode at the resolution of 100 ms.

Time synchronization usage

The IRIG-B time-code is used only for setting the internal time clock of the HIL Device, which is mandatory for various communication protocols in which data packets are timestamped.

To better understand the usage of time synchronization, three cases will be described:
  • HIL working in standalone mode (without IRIG-B)
  • HIL connected to PC (without IRIG-B)
  • HIL with IRIG-B connection
Table 1. Time synchronization usage explained
HIL Configuration Description

HIL working in standalone mode

When HIL is tuning in standalone boot, without the connection to PC, the HIL time will start counting from 1st of January 1970. All the network messages (coming from the communication protocols) will be stamped with this time value.

HIL connected to PC

When HIL is connected to the PC, every time the simulation is started, the current time is read from the PC and that time is applied to the HIL.

HIL with IRIG-B connection

When IRIG-B is connected, the exact time information is received every second and the HIL time is updated constantly, assuring that all the network messages have the correct time stamp.
Multi HIL Setup

When dealing with a multi HIL setup, every HIL Device has to be connected to the IRIG-B unmodulated signal. Please consult the documentation of the IRIG-B time-code generator for a multi device connection.