7i76 Spindle VFD 0-10V question
You could tweak the VFD scaling, but you will probably find that it can only be exactly right at one speed. The only way to get better than that is probably to set it up under closed-loop control. And, to be honest, it probably isn't critical to have exact speed to 0.1%.
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Encoder is working fine. Constact surface speed is working
Stupid question maybe but will the speed difference be a problem for threading?
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Somehow I thought the TB4 pins are TTL level only ... (5Volt)
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Is there no electrical signal conversion needed to connect the +24V VFD (pin 12) signals to the pin 6 and 8 of TB4 of the 7i76 board?
The spindle control pins are effectively solid-state switches. From the manual:
SPINDLE ISOLATED OUTPUTS
The 7I76 provides 2 isolated outputs for use for spindle direction control, and
spindle enable. These outputs are OPTO coupler Darlington transistors. They are all
isolated from one another so can be used for pull up or pull-down individually. They will
switch a maximum of 50 mA at 0 to 100 VDC. The SPINENA output is special as it uses
the same signal that enables the analog output. When the analog output is enabled, the
SPINENA OPTO output is on.
Be aware, though, that they are polarity-sensitive, so should be wired (for example) with 24V to + and then the VFD pin to -. Or, if the VFD is active low, with the VFD pin to + and the - pin to VFD control 0V / common.
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I'm curious to see where the information you shared, comes from as I didn''t find it yet myself (that shows mainly my incapability of finding specific info on the internet
![;) ;)](/media/kunena/emoticons/wink.png)
So then I understand why this indeed would work
7I76 TB4 ==> VFD (DANFOSS VLT2800 and others)
1 SPINDLE- ==> ANALOG COMMON VFD 55
2 SPINDLE OUT ==> ANALOG INPUT VFD 53
3 SPINDLE+ ==> 10V OUT VFD 50
4 NC
5 SPINDLE ENA- ==> START VFD 18
6 SPINDLE ENA+ ==> +24V VFD 12
7 SPINDLE DIR- ==> REVERSE VFD 19
8 SPINDLE DIR+ ==> +24V VFD 12
Thanks a lot for confirming
![:) :)](/media/kunena/emoticons/smile.png)
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Look up the 7i76
Click the "Specification" link.
There is a link to download the manual.
Or, alternatively, for any Mesa card type the card name and "man" into Google. For example "7i76man"
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![:) :)](/media/kunena/emoticons/smile.png)
I must have overlooked it initially
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