If measurement signals need to be referenced over time with each other for processing and analysis, they must be recorded synchronously.
All SomatXR modules can be synchronized among themselves. This ensures simultaneous measurement on all channels. All the analog‑digital converter rates, measuring rates and bridge excitation voltages are also synchronized.
To achieve a precise reference over time, the applicable channels must be parameterized with the same filter settings. No automatic runtime correction is carried out. The filter runtimes are shown in the data sheet. After booting and successful synchronization, the system LED shows green. If synchronization is disturbed, or not yet established, the system LED shows orange.
Time stamps are appended to the measured values in the following format:
Feature | PTP | NTP | FireWire |
---|---|---|---|
Synchronization with other devices | QuantumX (B series)
SomatXR CX23-R |
Quantum X MGCplus other |
QuantumX |
Maximum distance between modules | 100 m | 100 m | 5 m (40 m with FireWire extender, 500 m via optical fiber) |
Number of modules | Unlimited | Unlimited | 24 |
Accuracy | < 1 µs | < 10 ms | < 1 µs |
Settling time | Immediate | approx. 2 hrs during start approx. 10 min during restart |
Immediate |
Master | External PTP time-server
MX Module CX23-R |
External SyncMaster | MX module |
Voltage supply | None | None | 1.5 A looped through |
Each SomatXR module can accurately and reliably synchronize its internal clock using PTP synchronization. This is achieved using multiple Ethernet connection through an Ethernet switch.
The grandmaster clock in a network is selected automatically according to a master clock algorithm.
To avoid destroying the synchronization quality in heavy loaded networks, it is recommended that special PTP switches be used. The switches should support transparent clock with either E2E (end-to-end) or P2P (peer-to-peer) to compensate for the delay in the network.
Each SomatXR module can synchronize its internal clock with an NTP server. The NTP time is distributed to the other modules using multiple Ethernet connection through an Ethernet switch or via FireWire. Modules located close together should be synchronized via FireWire if available.
It is possible to achieve accuracies of 1 ms or higher depending on the utilization of the network and whether a dedicated NTP master is being used.
An NTP software package is included in the HBM software catman®EASY.
When using only SomatXR or QuantumX MX modules in close proximity (less than 5 m), it is recommended to use FireWire connections for synchronization. All the modules are synchronized automatically when they are connected via the FireWire cable. For more information on FireWire connections, see Connecting Multiple Modules to Host PC.
In a standard configuration, the module with the highest serial number takes over the master function. If a CX27 module or external synchronization source is present in the system, it automatically becomes the synchronization master. When starting the system, the system time is set once to the actual time.
If SomatXR and QuantumX MX modules alone are being used, internal synchronization is sufficient. However, if synchronous measurements are to be performed by different measurement systems, an external NTP or PTP master must be used for synchronization. This is also a requirement if the MX modules are a long distance away from one another and a FireWire connection would be too complex.
If an external synchronization source is set, the module with the best synchronization quality automatically becomes the master and synchronizes all modules connected via FireWire.