Mitsubishi VFD Modbus cant get it work

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4 years 9 months ago #231979 by hitchhiker
Replied by hitchhiker on topic Mitsubishi VFD Modbus cant get it work
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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4 years 9 months ago #231980 by cmorley
Replied by cmorley on topic Mitsubishi VFD Modbus cant get it work
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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4 years 9 months ago #231992 by hitchhiker
Replied by hitchhiker on topic Mitsubishi VFD Modbus cant get it work
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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4 years 9 months ago #231993 by cmorley
Replied by cmorley on topic Mitsubishi VFD Modbus cant get it work
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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4 years 9 months ago #231997 by hitchhiker
Replied by hitchhiker on topic Mitsubishi VFD Modbus cant get it work
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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4 years 9 months ago #231999 by cmorley
Replied by cmorley on topic Mitsubishi VFD Modbus cant get it work
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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4 years 9 months ago #232000 by hitchhiker
Replied by hitchhiker on topic Mitsubishi VFD Modbus cant get it work
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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4 years 9 months ago #233166 by jpg
Replied by jpg on topic Mitsubishi VFD Modbus cant get it work
Hello, is your configuration working now ?

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4 years 9 months ago #233168 by hitchhiker
Replied by hitchhiker on topic Mitsubishi VFD Modbus cant get it work
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

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4 years 9 months ago #233185 by jpg
Replied by jpg on topic Mitsubishi VFD Modbus cant get it work
do you have a configuration? (hal ,ini custom panel..) so I can try it, thanks

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