Reverse Run
09 Mar 2021 19:46 #201591
by mwinterm
Reverse Run was created by mwinterm
Hello,
I'm using LinuxCNC 2.8.1. The release notes of 2.8.0 state that there is a new feature for reverse run:
Reverse-Run: Negative feed-override will now run the G-code path in reverse.
I'm using the following set-up for the feed-override:
However when I now input negative values for halui.feed-override.counts the resulting halui.feed-override.value is just 0 and no reverse movement (see below):
Not sure if I'm missing out here something... Any help appreciated...
Best regards,
Marc
I'm using LinuxCNC 2.8.1. The release notes of 2.8.0 state that there is a new feature for reverse run:
Reverse-Run: Negative feed-override will now run the G-code path in reverse.
I'm using the following set-up for the feed-override:
Component Pins:
Owner Type Dir Value Name
10 bit IN TRUE halui.feed-override.count-enable
10 s32 IN 100 halui.feed-override.counts <== _feed_override_int
10 bit IN FALSE halui.feed-override.decrease
10 bit IN TRUE halui.feed-override.direct-value
10 bit IN FALSE halui.feed-override.increase
10 float IN 0.01 halui.feed-override.scale
10 float OUT 1 halui.feed-override.valueHowever when I now input negative values for halui.feed-override.counts the resulting halui.feed-override.value is just 0 and no reverse movement (see below):
Component Pins:
Owner Type Dir Value Name
10 bit IN TRUE halui.feed-override.count-enable
10 s32 IN -62 halui.feed-override.counts <== _feed_override_int
10 bit IN FALSE halui.feed-override.decrease
10 bit IN TRUE halui.feed-override.direct-value
10 bit IN FALSE halui.feed-override.increase
10 float IN 0.01 halui.feed-override.scale
10 float OUT 0 halui.feed-override.valueNot sure if I'm missing out here something... Any help appreciated...
Best regards,
Marc
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09 Mar 2021 21:12 #201595
by andypugh
Replied by andypugh on topic Reverse Run
I think that there is an error in the release note. (I will correct it)
It isn't feed-override which enables reverse-run, it is negative adaptive-feed.
You need to set motion.adaptive feed to a negative value. (typically this would be done with some form of sensor, rather than with a jogwheel)
From the motion manpage:
motion.adaptive-feed IN FLOAT
When adaptive feed is enabled with M52 P1, the commanded velocity is multiplied by this value. This effect is multiplicative with the NML-level feed override value and motion.feed-hold. Negative values are valid and will run the G-code path in reverse.
It isn't feed-override which enables reverse-run, it is negative adaptive-feed.
You need to set motion.adaptive feed to a negative value. (typically this would be done with some form of sensor, rather than with a jogwheel)
From the motion manpage:
motion.adaptive-feed IN FLOAT
When adaptive feed is enabled with M52 P1, the commanded velocity is multiplied by this value. This effect is multiplicative with the NML-level feed override value and motion.feed-hold. Negative values are valid and will run the G-code path in reverse.
The following user(s) said Thank You: Mike_Eitel
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10 Mar 2021 22:34 #201737
by mwinterm
Replied by mwinterm on topic Reverse Run
Thanks, works like a charm 
PS: ...why this needs to be enabled by M52 P1 and is not active by default? Would not hurt as long as adaptive-feed is not modified....
PS: ...why this needs to be enabled by M52 P1 and is not active by default? Would not hurt as long as adaptive-feed is not modified....
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10 Mar 2021 22:43 #201739
by andypugh
Replied by andypugh on topic Reverse Run
I think it has a G-code switch because it was originally intended to be driven by a spindle load meter, and you might not want that all the time.
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