Mitsubishi VFD Modbus cant get it work

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16 Jan 2022 00:56 #231979 by hitchhiker
the scale is only ×.... with a second math function like ÷.. its more usefull.


linuxcnc is great... mach3 needs hardware like ess smoothstepper.. with linux you can use a old pc... its great

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16 Jan 2022 01:02 #231980 by cmorley
I don't use divide because of divide by zero problem - you can multiple by reciprocal
ie. divide by 10 = multiply by 0.1

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16 Jan 2022 09:03 #231992 by hitchhiker
ie. on mach3 the spindle rpm wish is for my setup:

A/0.28

A is the value for the rpm

if A 2800 it sends 100.. 100 Hertz.
max rpm motor 2850 at 100 Hertz.

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16 Jan 2022 09:40 #231993 by cmorley
Math seems wrong:
2800 / 0.28 = 10 000 not 100
maybe a typo?

2800 / 28 = 100
or
2800 x (1/28) = 100
2800 x 0.03571 = aprox 100

So you can get the same output using a multiplied scale.
It avoids a program crash for divide-by-zero, without having to have code to specifically check for it.

Chris

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16 Jan 2022 10:11 #231997 by hitchhiker
this is from the mach3 Board 

www.machsupport.com/forum/index.php?topic=27490.0

i use 0.28 to match the correct value for wish = is rpm.

because i have a transmission of input from the motor and output on the spindle its not 1 to 1... i measure the spindle revs. with a encoder.. on the complete bandwith i have a error of 10rpm.
 
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16 Jan 2022 10:28 #231999 by cmorley
ahh yes modbus doesn't officially handle floats.
if you want 65.55 hertz you multiply it by 100 to get 6555.
then 100 hertz would be 10000.

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16 Jan 2022 10:36 #232000 by hitchhiker
yes... know the price question... what value is need to multiplie..

how difficult is it to bring the dividing option for scale into the code?..

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26 Jan 2022 12:34 #233166 by jpg
Hello, is your configuration working now ?

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26 Jan 2022 13:13 #233168 by hitchhiker
yes but its npt modbus rtu.
the comp. is for the mitsuboshi com. protocol.

npw i must use a second rs485 dongle for my other modbus parts
The following user(s) said Thank You: jpg

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26 Jan 2022 15:56 #233185 by jpg
do you have a configuration? (hal ,ini custom panel..) so I can try it, thanks

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