CoaXPress camera detection
- Detection process description
- Camera detection types
- Camera Discovery Delay
- Command Timeout Control
- Hardware related issues
- Camera Verify Discovery Speed
- Redetection at CXP-10\12 known issue
Detection process description
According to the CoaXPress standard there are two type of connection between the Frame Grabber and the Camera.
- The High Speed Connection is the Downlink from the Camera to the Frame Grabber.
- Stream (image) data
- The Low Speed Connection is the Uplink from the Frame Grabber to the Camera.
- IO for real-time triggers (a trigger event occurs when a trigger frame is received)
- Device control (from host to read and write device control registers)
When High Speed Connection is from CXP-1 to CXP-6 then the Low Speed Connection is 20.83 Mbps
When Low Speed Connection is CXP-10 and CXP-12 then the Low Speed Connection is 41.6 Mbps.
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Camera detection types
The camera discovery (detection) process is available on either one of two speeds: 1.250 Gbps or 3.125 Gbps.
High Speed | Low Speed | ||||
---|---|---|---|---|---|
Bit Rate | CXP | Bit Rate Code | Discovery Speed | Bit Rate | |
1.250 Gbps | CXP-1 | 0x28 | Yes | 20.83 Mbps | |
2.500 Gbps | CXP-2 | 0x30 | No | 20.83 Mbps | |
3.125 Gbps | CXP-3 | 0x38 | Yes | 20.83 Mbps | |
5.000 Gbps | CXP-5 | 0x40 | No | 20.83 Mbps | |
6.250 Gbps | CXP-6 | 0x48 | No | 20.83 Mbps | |
10.000 Gbps | CXP-10 | 0x50 | No | 41.6 Mbps | |
12.500 Gbps | CXP-12 | 0x58 | No | 41.6 Mbps |
Camera Discovery Delay
The camera discovery delay sets the delay time before camera discovery is initiated. The discovery delay is set in milliseconds and waits for the specified time after the camera scan call is initiated. At the end of the specified period, the camera discovery process will start according to the configured camera discovery mode.
This could be helpful if the camera is not fully compliant with CoaXPress standards.
Command Timeout Control
Before camera detection, the camera command timeout can be increased for cameras with longer reponse than the default value.
For multiple camera detection, the Camera Command Timeout should be modified for all the cameras, according to the camera with the longest initialization period, to ensure proper camera detection. This option is located in the Vision Point application under the Frame Grabber tab “Control” category, as shown in the image below.
This could be helpful if the camera is not fully compliant with CoaXPress standards.
Hardware related issues
The first step in troubleshooting a CoaXPress connection is to verify the compatibility of the coaxial cable with the system requirements. Ensure the cable meets the specifications outlined in the system’s data sheets, including bandwidth and length limitations.
- Check Compatibility:
Confirm that the cable type and specifications match those required by your system. Refer to the manufacturer’s data sheets. - Inspect Physical Condition:
Examine the cable for any physical damage, such as bends, kinks, or wear that could impact performance. Ensure connectors are securely attached and free of debris or corrosion. - Verify Connections: Confirm that each end of the cable is properly connected to the correct ports and that they are fastened securely.
If compatibility and physical integrity are confirmed, but issues persist, further diagnostics may be needed, such as testing with a different cable or checking for possible signal interference.
Camera Verify Discovery Speed
In some cases with CoaXPress cameras can not be detected due to Connection Config Default settings. Try enabling the 'Camera Verify Discovery Speed' option before the camera detection process. In Vision Point legacy this option is in the Frame Grabber properties window under the 'Device Control' section.
Redetection at CXP-10\12 known issue
There is a known issue with cameras that are causing redetection failure at CXP-10\12 speed. The cause of the problem is the Timeout of the Low Speed Connection, which controls how long time the Camera will stay on a current value of Low Speed Connection when the Frame Grabber sync is lost.
- In Normal Camera Discovery process the Frame Grabber checks and switches to "Connection Config Default" of the camera, for example, to CXP-12 speed.
- Both the Camera and the Grabber are synchronized on a "Low Speed Connection" of 41.6 Mbps in case of CXP-12.
- In case of recurring normal Camera Discovery the Frame Grabber sends "reset" command and switches back to 1.25 Gbps that corresponds to "Low Speed Connection" of 20.83 Mpbs, and checks if the camera is on the same speed.
- Meanwhile the camera's "Low Speed Connection" is 41.6 Mbps, so it looses synchronization with the Frame Grabber. This happens because of a too long timeout defined in "ConnectionLowSpeedTimeout". With the standard value of this timeout, 200ms, camera detects lost connection and drops it's low speed to 20.83 Mbps soon enough after grabber switches to 20.83 Mbps. But if this parameter is too large, say 10 full seconds, then after switching the grabber to 20.83 Mbps, the camera remains at 41.6 Mbps while the user tries to re-discover it. Since the low-speed configuration differs between the grabber and the camera, the 'Reset' command sent from the grabber doesn’t reach the camera, leading to a failed detection process.
- The Camera receives reset command after the timeout is expired, and switches to the Camera Discovery Speed which is "Low Speed Connection" to 20.83 Mbps, and only then camera becomes available for detection.