Dalsa C1240, Руководство пользователя

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222 • Operational Reference Nano Series GigE Vision Camera
Overview of Precision Time Protocol Mode (IEEE 1588)
PTP Mode = Precision Time Protocol
• The PTP protocol synchronizes the Timestamp clocks of multiple devices connected via a
switch on the same network, where the switch supports PTP.
•
For optimal clock synchronization the imaging network should use one Ethernet switch.
Daisy-chaining multiple small switches will degrade camera clock syncs.
•
Additionally the Ethernet switch connecting cameras to the imaging network should
implement “PTP Boundary Clock” hardware.
•
To use a multi-port NIC adapter or computer with multiple NIC ports instead of a switch,
that multiport NIC must be capable to be configured as the common Master PTP source for
all its networks. Such a configuration requires using the multi-port NIC’s configuration
software.
•
Genie Nano cameras can automatically organize themselves into a master-slave hierarchy,
or the user application configures a camera master with n-number of slaves. The auto-
configuration process typically happens within 2 seconds.
•
The automatic organizing procedure is composed of steps (as defined by IEEE 1588) to
identify the best clock source to act as master. When only Nano cameras are used, since
they are equal, the last selection step is to identify the Nano with lowest value MAC address
to be the clock master.
•
The feature TimeStamp Source is automatically changed to IEEE1588 when PTP Mode is
enabled. This timestamp tick (in ns) cannot be reset by the user.
•
The Genie Nano cameras implement additional features designed to synchronize multiple
camera acquisitions via IEEE 1588 (PTP Mode) – not via external camera trigger signals.
PTP Master Clock Identity
The clock ID of the current best master is an Extended Unique Identifier (EUI)-64 “64-bit ID”,
converted from the 48-bit MAC address, by inserting 0xfffe at the middle of the MAC address.
• The standard MAC address in human-friendly form is six groups of two hexadecimal digits as
this example shows (excluding hyphens ): “0a-1b-2c-3d-4e-5f”
• The Extended Unique Identifier format is (excluding hyphens): “0a-1b-2c-fffe-3d-4e-5f”
An Example with two Nano Cameras
The following basic steps configure two Nano cameras connected to one computer via an Ethernet
switch, configured with two instances of CamExpert, to grab a frame every second, controlled by a
modulo event via PTP.
For each camera set features as follows:
I/O Controls — select Trigger Mode=ON, Tigger Source=Timestamp Modulo Event
Event Controls — select PTP Mode=Automatic
• Note how one Nano automatically becomes Master while the other becomes Slave
Event Controls — to have a modulo event every second, set Timestamp Modulo
Event=1000000000
Click Grab on each instance of CamExpert. With the two cameras aimed at the same moving
object, you see that each camera grabs a frame at the same time.