Vision: troubleshooting

Last updated

License feature: Machine Vision

Camera and connection

Symptom	Cause	Fix
Device will not connect: "Vision cannot run: …"	The appliance's image-processing component is missing	Reinstall or update the appliance software, then restart the drivers from the Appliance page
"No image from Camera 1 (Camera returned HTTP 404)"	Wrong path for this camera's firmware	Open the URL in a browser; set the correct one in URL (optional)
"… Camera returned HTTP 401"	The camera needs a login	Set Camera username and Camera password when adding the device; the Vision page has no login fields — see Cameras
"No camera IP configured." / "No snapshot URL configured." / "No stream URL configured."	The address or URL field is empty	Fill it in and Save
"No test image uploaded."	Uploaded test image chosen with no file	Upload an image under Test image
"Could not read the test image at …"	The file was deleted, or the configuration came from a selective export rather than a full backup	Upload the image again
"Could not open camera source 0"	No USB camera at that number, or another program has it	Try Camera number 1; unplug and replug; check nothing else uses the camera
"The camera did not return a frame. It may have disconnected."	USB camera unplugged or stream ended	Check the cable or stream; the next grab reconnects
Timeout after about 5 s	Camera unreachable or very slow	Check network and IP; a camera on another subnet needs routing
The picture never changes although the part does	The camera serves a cached image	Put {cb} in the Snapshot URL, e.g. http://cam/snap.jpg?t={cb}
Preview shows "Preview failed." or a 502 error	The device is not connected, or the drivers service is down	Check the device's status on the Devices page; connect it

Results

Symptom	Cause	Fix
Count is one or two high	Noise, highlights or the tray edge counted	Draw a tighter region; raise Min radius/Min area; raise Cleanup (Blobs); raise Sensitivity (Circles)
Count is low	Parts missed	Lower Sensitivity; widen the radius or area window; check Invert (Blobs)
One part counted twice (Circles)	Min distance too small	Raise it towards the part diameter
Verdict reads Nothing checked / pass uncertain	No tool is judged, or judged tools have no target/limits	Tick Include this tool in the verdict and set Expected count or a limit
Presence reads high on an empty fixture	Automatic threshold on a flat region, or threshold on the wrong side	Set Threshold between the empty and good readings; check Invert
Color match reads 0% on the right part	Saturation or brightness floors too high, or wrong hue	Use the color in view; lower Ignore below this saturation
"Nothing taught yet. Draw a box round the feature and press Teach."	Pattern tool not taught (its own tags read bad; if it is judged, pass reads false)	Teach it, or remove the tool, and Save
Pattern score low on a good part	Lighting or camera changed since teaching; part rotated	Teach again; or allow Search angles
Following tools fail with "… did not find the part."	The locator's score is below its At least	Check the locator; lower its limit carefully, or teach again
Caliper reads too wide	The region crosses another edge beyond the part	Narrow the region; set Which edges
Gauge limits suddenly wrong after setting a scale	Limits were set in pixels	Re-enter the limits in mm
Text reads ? for some characters	Character not taught, or below Confidence needed	Teach that character from another label; check the print quality
"Found 6 characters in the box but was told it says…"	Characters touching or split	Adjust Gap between characters and Threshold; draw the box tightly
Barcode not read	Code too small or low contrast	Upscale 2; better lighting; draw a region round the code

Tags and saving

Symptom	Cause	Fix
New tool's tags do not exist	Not saved yet	Press Save; the tags are created on save
Changes on the page have no effect on the line	Not saved, or the device was disconnected when saved (it picks up settings when it next connects)	Save with the device connected, or reconnect it
One tool's tags are bad	That tool errored (not taught, no image from its camera, a locator it follows did not find the part)	Read error (or the tool's red message on the Vision page) and fix that
Every tag on the device is bad	The whole inspection failed	Read error and fix that
Tool results uncertain after a recipe ran	A changeover invalidates results until the next inspection	Expected — trigger an inspection
Writing trigger from the tag browser fails with "Write access is not enabled for this device…"	Allow Tag Writes is off	Turn it on in the device's settings
"Trigger missed: the previous inspection sequence was still running."	Triggers faster than the sequence completes	Shorten Wait steps, raise the source's debounce, or slow the trigger
"tool '…' is not in the running program '…'. Change over first, then set it."	A setting written for another product	Write program first, then the setting
Save fails: "Tool "…" is a circles tool in "…" and a barcodes tool in "…"…"	Same tool key, different types in two programs	Give one of them a different Tag prefix
Statistics counts reset unexpectedly	Save, changeover, Reset counts or restart	Use the window figures from the historian for shift yield

Performance on a Pi

• Watch last_run_ms (and the ms figure beside the verdict). Big frames cost most: a 5 MP JPEG takes far longer to decode and search than a 1 MP one. Set the camera to the lowest resolution that resolves the feature.
• Regions make every tool faster, especially Pattern match.
• Search angles multiplies pattern time by the number of angles.
• In Continuously mode a device inspects on every poll; with a 1000 ms polling rate and a 700 ms inspection there is little spare. Use a trigger or a slower poll.
• Keep every inspection writes a JPEG per inspection to the SD card or eMMC; use it for fault-finding only.

See also

• Machine Vision
• Vision: cameras and connection
• Vision: tags reference
• Vision: triggers, strobes and lighting