Synchronization
Synchronization means that a clock provider sends a clock signal from a time source to a clock slave(s). They are synchronized because they use the same clock signal.
Devices can be synchronized in two ways:
- Software synchronization - The accuracy is between 2 and 10 ms, which is enough for a simple measurement, e.g. temperature. This solution requires no additional hardware.
- Hardware synchronization - This solution can synchronize all USB devices (SIRIUS, DEWE-43,…) and EtherCAT devices (KRYPTON).
NOTE: If you have received a SYNC LOST message in DewesoftX, check the following troubleshooting steps.
Time Source
You can choose a clock for synchronization from Options - Settings - Synchronization. The options are automatically adjusted depending on devices connected to your system. In general, you can choose from:
- Dewesoft DAQ Devices - if there is a Dewesoft measurement device connected
- External - Clock/Trigger, IRIG-B DC, NTP, GPS PPS
- PC clock - when there is only a computer without a measurement device
- GPS devices - Dewesoft RS232 (Topcon/Javad/NVS), NMEA compatible GPS,…
NOTE: Synchronization types are dependent and automatically adjusted from the DAQ devices connected to our system.
Types of Synchronization
If either Dewesoft DAQ Devices or External is selected as a time source, you will be able to choose a clock provider/type of synchronization:
- Automatic - automatically selects the best option for synchronization taking into account the connected hardware.
- Standalone - only one device, i.e. no synchronization needed.
- SoftSync - this synchronization solution requires no additional hardware. The accuracy is ~10 ms.
- Clock/Trigger - a clock and a trigger signal are used. A sample is acquired on each trigger signal.
- IRIG-B DC - Contains time-of-year and year information in a BCD format. This is the most precise way to synchronize devices.
- GPS PPS - Since satellites are transmitting the exact absolute time and high-quality receivers usually output this pulse with a precision of <1 ms, we can use this technology to synchronize remote systems because there is no distance limit.
- Network Time Protocol (NTP) - A networking protocol for clock synchronization between computer systems, less accurate than other methods.
To enter the addresses of the NTP server, click the edit button on the right of the dropdown menu. If you want to have multiple devices synchronized via NTP protocol, the same server address must be entered into all of them.
When you Check NTP servers, the time and date of the server will be displayed. If the server address is wrong, the check will fail.
If synchronization via NTP is successful, the clock icon next to the time will be green:
If something is wrong, the clock will become red and the Sync lost message will appear:
Synchronization Between Dewesoft USB Devices
| Type | Accuracy | When to use | Device |
|---|---|---|---|
| Clock/trigger | ~ 1 us | Stationary | Dewesoft, RoaDyn… |
| IRIG-B DC | ~ 1 us | Stationary | Dewesoft, Meinberg,… |
| GPS PPS | ~ 1 us | Mobile | GPS receiver |
| NTP | + 10 ms | Ethernet | NTP server |
| NTP | + 10 ms | When there is no external time source |
Any Dewesoft device can be precisely synchronized via hardware (Sirius, Dewe-43, Minitaur, DS-CAN2).
When using the NET system, there are several options for synchronization:
- Clock/trigger - relative time
- IRIG-B DC Master / IRIG-B DC Slave - absolute time
- GPS - absolute time
- NTP - absolute time
Example - Clock/trigger connection:
Example - IRIG-B DC connection:
- Dewesoft device as an IRIG-B DC generator
- External IRIG-B DC provider
Example - GPS PPS connection:
Dewesoft device has a GPS receiver
External GPS receiver
Example - NTP connection:
Synchronization with ECAT-SYNC-JUNCTION
ECAT-SYNC-JUNCTION works in the same way as other Dewesoft devices. It is automatically recognized within Dewesoft X software (supported in version X2 SP4). By default, ECAT-SYNC-JUNCTION will be set up to synchronize between KRYPTON EtherCAT® and SIRIUS USB.
Several connection options are possible:
- Synchronization of SIRIUS/DEWE-43 USB with KRYPTON/SIRIUSiwe EtherCAT® devices with an accuracy of ~1 ms
- Synchronization of KRYPTON module with an external IRIG B DC triggering source
- Synchronization of KRYPTON and SIRIUS USB with an external IRIG B DC triggering source
- Synchronization of KRYPTON/SIRIUSiwe with triggered cameras
- Synchronization of SIRIUS/DEWE-43 USB with KRYPTON/SIRIUSiwe and triggered cameras
Troubleshooting
In case of issues, essential troubleshooting steps would be checking:
- Synchronization cable (L00B4m-L00B4m)
- Check if the LEMO connectors are loose.
- If possible, exchange the cable with another to eliminate the possibilty of a faulty cable.
- The length of the cable in the whole chain (from the first device to the last) can not exceed 100m if IRIG synchronization is used. If the cable is longer, we suggest using an IRIG buffer.
- Synchronization source in software settings
- If you always get Sync lost when a particular device is used as the master source for synchronization, it may have a hardware problem. Change the synchronization source to another device if possible.
- If you have selected an External synchronization source, verify its feasibility, e.g. if you use a GPS PPS source, check that enough satelites are found and a valid pulse can be created.