On 5/4/25 08:00, Stuart Stevenson wrote:
Are you trying to see the index pulse on every revolution of the encoder?
On Sun, May 4, 2025 at 6:45 AM Nicklas SB Karlsson <n...@nksb.eu> wrote:
It is an ordinary very common encoder have with a zero output. It does not
have any index-enable net just an output. All
encoders I have seen with an index output have been like this so therefore
assume it is a very common problem how to
connect these and simple solution available.
I could of course create an index net or write a component with an IO
output that write value only then edge is
detected. Then it will be possible to connect this to joint index-enable
as both are IO.
Nicklas Karlsson
That depends on the encoder, Optical looks the same regardless of
direction of approach, hall effects have a false trigger as it
approaches, followed by the wanted crossing edge several degrees later.
so if exact crossover point is wanted the edge detected needs to be
switched with the direction control sent to the motor controller, true
in both cases in order to match the spindle position for both approach
directions. This is not needed for g76 threading, nor for rigid
tapping, only for a tool changer requiring exact positioning to engage
the drive dogs. So only one of my machines which have spindle encoders
is so equipt. The go704, whose index only is hall effect, the sheldon is
all 3 signals by hall effect, ats-667's. the go704 encoder is optical,
on the rear of the motor and has a gear shift between the index pulse
and the encoder, so there is no fixed relation between the motor
encoder and the index. The only place the index signal is actually used
is as the start trigger for rigid tapping or G76 which is always with
the spindle turning forward. There is no need to select the edge used
as index in those operations.
On the go704, that spindle encoder is on the rear of the motor which can
approach 21k revs because of the gear ratios in the head, and the
encoder is balanced output 1000 ppr unit feeding an opto-less parport
card, directly into a 5i25 thru rs485 balanced to TTL convertors. In
over a decade it has never missed a count even at 35 volts over the
motors 90 volt ratings. very close to 3000 spindle revs. Still on the
OEM brushes.
sön 2025-05-04 klockan 10:26 +0100 skrev andy pugh:
On Sun, 4 May 2025 at 09:26, Nicklas SB Karlsson <n...@nksb.eu> wrote:
Any simple solution to connect index pulse from encoder to joint
index-enable?
Are you sure you want to do that? Why?
Typically the system sets the whole index-enable net, then when the
index pulse is seen it is taken low by the encoder counter, that
signals to the rest of the net that the index has been seen,
Are you trying to home to index without an encoder counter?
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