playing around, hoping to make up a tester for Fanuc serial encoders- made a remote jog box for moving servos for old robots, but cant use on 'newer' (after mid 1990s) ones with serial encoders, and still have no real way to test serial encoders...seems a cheap little tool with a lcd to check/display pulses/rev, marker, commutation,would be nice- plus outputting commutation could pass thru and use my jogbox to move robots in storage(unfolding/folding disconnected robots to access parts/fit in elevator of storage building/etc).
bought some little 422/ttl adapters, but dont appear baud can exceed 1m on the arduino ttl side...know 422 can run much faster, but what arduino might use sub-microsecond i/o reads, or is there a simple 422 setup I just havent seen?
thanks in advance for any insight on this...really think posting a program/schematic for a cheap DIY tester could make life easy for a lot of CNC/Robot maintenance techs...same device could likely be easily tweaked for any manufacturers serial protocols too... Fanucs is a odd 77 bit stream, Ive found the commutation data in it with a scope, but need a way to read it and output the four commutation tracks, and maybe emulate the quadrature equivalent for velocity, the older amp I use for the jog box has built in f/v converter to simulate tach onboard...just seems a almost ideal tool could be made with a little Arduino or Raspberry Pi...
1M baud leaves 16 clock ticks for a software driver on a 16 MHz Arduino. You'll need a much faster Arduino for such an approach.
A hardware UART instead can work on up to 2M baud, see the data sheet of your controller.
Could that be 7 bytes of a 8E1 serial stream?
A logic analyzer could reveal more...
ESP32? STM32 blackpill? All are much faster than the basic 16MHz arduino.
unfortunately, no- Fanuc just outputs one 77 bit word after a single bit request strobe is sent
thanks- I'll look into those devices too
How do you know?
according to some obscure fanuc documentationI found- scope/timing verified, and since have seen other scales and such with compatible 77 bit serial interfaces(one said 5 characters are crc validation)...shouldnt have said 'word' so much as stream...on scope from years ago, recall some groups of 16 bit position counts, difference since last inquiry, velocity, and commutation were kinda chunked together, but in different length groups
Then there HAS to be an associated clock to allow the receiving device to count when more than one zero bit or more than one 1 bit are in a group.
all I've seen was it runs at 1,024,000 baud rate- 77 bits at a open loop synch by baudrate alone don't sound right, but think thats how it runs...imagine start/end characters to verify frame rates are close enough to synch would be needed? dont know, but thats what i'm hoping to pick up and sort out...i'm not a computer designer, just a self taught machine tool guy, this stuffs all over my head or at least close 
have made quite a few tools to help keep our old stuff running/make testing stuff easier for other maint guys that dont really get into the electronics stuff at all- a cheap/simple serial encoder tool would be a awesome thing to have available. and if it had quadrature and commutation emulating outputs, I could use it on my 120v 'jog box' for moving slides/folding robots without controls without 3 phase and all the associated wiring attached...I can do that on the old quadrature encoder robots, but they are all obsolete and discarded now...but we have hundreds stored and often need to like rotate 5th axis to gain access to 6th mounting bolts, that type of thing... just sure seemed right up the alley for a arduino type application...
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