7i47s documentation verbage (analog i/o)

using the links colors in the "analog operation section

ANALOGOUT goes to RED.
ANALOG- goes to BLACK
GREEN goes to Spindle-GND
BLUE goes to Spindle-IN

This is a standard reversing switch
This will of course also work with a DPDT relay

(this does depend on a separate 15V floating supply)

Got it. Thanks!!!

Sometimes I really am thick.

andypugh wrote:

Would it be better to use a potential divider to drop the +15 to +7.5 and the -15 to -7.5 and to adjust the max output in the drive software?

Are you sure that the drive can't be configured for unipolar and reverse?

What drive software? The DC spindle motor controller is a 25 year old Lenze 493. docs.google.com/open?id=0B-r0kOumKPg2ZTA4MGtnUEFMcUE

According to the documentation, the english translation of which is rather terse, you can remove resistor r705 and place an attenuating potentiometer between pins 40 and 44 of the controller to adjust the max output.

The practicallity of doing that is questionable because then all the other pots must be rebalanced to rebias the field current.



That would also probably best be done by someone who is competent to wire a dpdt switch. ;^)

The Lenze is a working black box. My preferance is to make systems adjustements outside of such boxes.

Rgds
_jC
.

andypugh wrote:

I am a little nervous that zero-output from LinuxCNC is going to give you full speed reverse.

I think there is a dead band around the zero-crossing. Wiper to ground (the existing 5kohm pot in the console, or lifing the fwd/rev switch) stops the spindle.

Does the application actually need the motor to rotate in both directions? I don't think I have ever needed to run my lathe or mill backwards yet.

I'd like to be able to ridgid tap

----

Off topic. I have found inconsistancies between the machine documentation and the actual installation. I am now faced with surveying the machine and anotating the documentation before proceeding.

I am learning that there is a huge difference between theory and practice in executing a CNC conversion.

Cheers
_jC
.

_jC wrote:

That would also probably best be done by someone who is competent to wire a dpdt switch. ;^)

The Lenze is a working black box. My preferance is to make systems adjustements outside of such boxes.

Rgds
_jC
.

Just a short follow up on the above diagram. The sensitivity of the control voltage can be adjusted at voltage divider U-Leit. And maybe it is possible to limit the full range of the control voltage <= 15, and then bias the center to ground.

But then to stop the spindle the control voltage would have to be at some middle setting. I rather prefer a switch for fwd/rev and an analog control zero-to-max.

Still need to retrace and annotate the original control diagrams. There are quite some differences to what is actually installed in the machine.

Rgds and thx
_jC
.

This needing to be 1/2 way up for off is why is discouraged using this mode. I think the DPDT switch/relay is safer
(or using a designed for bipolar output device like the 7I33,7I48,7I77,7I83 etc)

andypugh wrote:

PCW wrote:

(this does depend on a separate 15V floating supply)

The easy way to get this would be to use a 15V to 15V DC/DC converter powered from the provided +15V
Something like: uk.rs-online.com/web/p/isolated-dc-dc-converters/7065063/

Noted. Thanks!