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Operational Reference
Linea Lite GigE Series Camera
Overview of Precision Time Protocol Mode (IEEE 1588)
PTP Mode = Precision Time Protocol
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PTP 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.
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To use a multi-port NIC adapter instead of a switch, it must be configured as the common
Master PTP source for all its networks. Refer to the NIC’s configuration software instructions.
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Linea Lite 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.
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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 Linea Lite cameras are used they are equal
and the Linea Lite with lowest MAC address value is set to 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 Linea Lite 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 Linea Lite Cameras
The following basic steps configure two Linea Lite 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
: one Linea Lite 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 frames simultaneously.
Preliminary
