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Limit switch level register?


KEJR
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In my ongoing quest to properly deal with limits using Macro and Copley drives on PPMAC I have discovered that the copley amp is halting my motor on its own when I hit the limit switch. Limits in the amp are configured and properly relayed to the PPMAC using the default macro register and bit location. To make the copley *not* react to the limits I have to tell it to treat the limits as a general purpose input which gets passed to Macro[n][1] register in bits 17&18 (this took me a while to figure out since the monitor screen seemingly shifts the register 8 bits from what Motor[n].LimitBits expects). So now I have the PPMAC recognizing the limits, but the polarity is inverted. Is there a register to reverse this polarity of the limit bits? While we are at it why is the bit position different in the monitor screen vs the motor setup data structures? Is this some attempt to make it like the old PMACs? If so it just makes things worse IMHO. If this doesn't work I'm going to switch to motor index channel homing and hope that that works with the copley/macro setup. Thanks, KEJR
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We have never had a polarity contro bit for the limits on any PMAC because we have wanted to force the more failsafe configuration of normally closed limit switches with the standard interface circuitry. We will be very hesitant to change this. The "LimitBits" setup element specifies the location of the resulting bits on Power PMAC's 32-bit data bus. The MACRO register elements are 16 and 24 bits at the high end of this bus.
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I understand your logic about the sense of the limit switch, but it gets muddy with the MACRO setup since the drive is reporting the limits. After talking with our copley distributor it seems that we can possibly do something in the drive, so that is possibly a different way around this. Thanks, KEJR
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  • 2 months later...
*** This problem is finally solved.*** While homing I disable the copley drive limits over the Macro link using a MacroSlave command to modify the Copley drive's input parameters. Once homing is done I re-assign the drive limit inputs to function as limit inputs once again and all is well.
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  • 9 months later...
[quote='KEJR' pid='1798' dateline='1303843090'] *** This problem is finally solved.*** While homing I disable the copley drive limits over the Macro link using a MacroSlave command to modify the Copley drive's input parameters. Once homing is done I re-assign the drive limit inputs to function as limit inputs once again and all is well. [/quote] KEJR, You can also set bit 2 of ms(node),I$4AF in the Copley to not affect current output on limit switch. You can avoid the temporary remap this way. G
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