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I have few questions about Samba PLC functionality. I searched things, but im not sure that i understand correctly. 

First about my project. I planning to use Samba PLC, to turn two stepper motors, via stepper drive, and some other simple things. Not very complicated machine, it just need to do simple tasks, like: Rotate 9,3times (or x steps), wait, rotate back 4 steps, rotate back, etc. Not very complex, and i think easily programmable. 

The question is that, i see Samba have HSO for step control. But that speed is 0.5khz (i dont understand difference pnp vs npn right now, apart wiring). Stepper motor and drive as i understand have 400steps/rotation. Lets say i want to spin motor at 200rpm. If hso output speed is 500hz, which means like 500pulses over a second, and that is 1,25 rotation in a second for a motor? That is like 75rpm. I need to spin the motors for at least 150-200rpm.. so this plc will not be able to do this, or am i missing something?

Sambas model: SM35-J-T20
I have chosen it because price is good, enough i/o

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  • MVP 2023

You are correct about the ridiculously slow frequency on regular PNP transistor outputs.  I discovered this the hard way on a stepper motor application many years ago.

Here's a post covering the difference between PNP and NPN - 

You need a Vision model with real high speed NPN outputs to do what you're trying to do.  There will be a "TR" in the part number if it has this.  That capability is one of the things Unitronics removed from the Samba series to make it lower cost.

The Vision version of the Samba you chose is a V350-J-TR20.  This model has the high speed outputs.

Joe T.

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Thanks for help!

It seems that my assumptions were correct. Said vision model (V350-J-TR20), has two high speed output. It seems that it is just perferct for my two stepper motor aplication, i can assign each output for each drive. Also thanks for pnp/npn!

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