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« on: August 07, 2020, 04:51:54 PM »
Hi,
the ESS has 51 inputs and outputs, whereas the 57CNC has 57.
The ESS is TTL input/output, that is 5V. It is expected that the ESS be partnered with a breakout board and
the MB3 by CNCRoom is a nice example. It has a mix of differential, 24V single ended and opto-isolated inputs and
outputs with proper screw terminals. Using such a breakout board means you do not EVER direct connect to the ESS.
So whether inputs and/or outputs are TTL level, that is 5V, or 24V, the industrial norm, depends on your choice of
breakout board not the ESS.
I've been using my ESS for six years and I've had one occasion, with several events over the course of an afternoon, where
I experienced electrical interference enough to stop the ESS. I was pushing my spindle to the very limits on that particular
job, but that is the only occasion that I've ever had a 'noise' problem.
I use a pair of MB2's from Homann Designs (not to be confused with the MB3 of CNCRoom, totally different animals) which
are single (parallel port equiv) port bi-directional TTL level breakout boards. You might argue that 5V signal levels are more noise
prone (than 24V), which is not in fact the case.....if....and ONLY IF....you choose the appropriate impedance level for your signaling circuit.
There is a rather complex (mathmatically) reason why this is so, and I could refer you to various texts, F.G. Stremmler, 'Introduction to
Commuication Systems' (Addison-Wesley, 2nd ed.), the chapter (4) on power spectral density, and Ramo, Whinnery and VanDuzer, 'Fields and Waves
in Communication Electronics' (Wiley & Sons, 3rd ed.), the chapter (5) on circuit concepts and impedance in the presence of EM waves is fundamental
to the 'noise' question.
With appropriate impedance design a 5V system can have the same noise immunity as a 24V system (with the same signal power).
Craig