Sounds interesting but as soon as you are heading into "very careful wiring" territory that smells like a recipe for someone like me to release the magic smoke. And that doesn't even cover the creation of what I am guessing must be custom firmware.
You can use the FPGA parallel expansion ports directly for TTL level interfacing _but_ they are susceptible to damage
from negative inputs if there is no current limiting, The inputs have protection diodes to ground but these diodes will only
take 20 mA or so. How do you get a negative input? say you accidentally connect an input pin to frame ground and you
have 1V of high frequency ground bumping from a VFD or axis drive, you lose... A 100 ohm series resistor will protect
against this fault
Interesting. But I'm not sure that will work based on how I understand the way the input pins work. They are referenced to field voltage and at 24V the 5V TTL will not be enough to get them to register as going high.
The 7I76/7I76E field inputs are all read as analog voltages (at about 50 KHz or so) so the threshold for MPG inputs is set in
software...
BTW I found the encmode RO issue in our config file: (all the encmode stuff should be bidir)
Code:
;7I76
00000001 0 hwmode Standard
00000001 0 swmode IO_Spin
00000010 1 swmode IO_Ana_Spin
00000100 2 swmode IO_Enc_Ana_Spin_FV
;00001000 3 swmode IO_Enc_Ana_Spin_FV
00001111 32 bits input 0.0 0.0 None Input
00001111 16 bits output 0.0 0.0 None Output
00001111 16 unsigned output 0.0 100.0 Percent SpinOut
00001111 8 Boolean output 0.0 0.0 None SpinEna
00001111 8 Boolean output 0.0 0.0 None SpinDir
00001110 8 unsigned input 0.0 36.3 Volts AnalogIn0
00001110 8 unsigned input 0.0 36.3 Volts AnalogIn1
00001110 8 unsigned input 0.0 36.3 Volts AnalogIn2
00001110 8 unsigned input 0.0 36.3 Volts AnalogIn3
00001100 16 unsigned input 0.0 36.3 Volts FieldVoltage
00001100 8 count input 0.0 0.0 Counts Enc0
00001100 8 count input 0.0 0.0 Counts Enc1
00000000 16 unsigned output 0.0 0.0 None SwRevision
00000000 16 unsigned output 0.0 0.0 None HwRevision
00000000 16 nonvolunsigned bidir 0.0 0.0 None NVBaudRate
00000000 32 nonvolunsigned input 0.0 0.0 None NVUnitNumber
00000000 16 nonvolunsigned input 0.0 0.0 None NVWatchDogTimeout
00000000 16 unsigned input 0.0 0.0 None EncMode0
00000000 16 unsigned input 0.0 0.0 None EncMode1
00000000 16 nonvolunsigned input 0.0 0.0 None NVEncMode0
00000000 16 nonvolunsigned input 0.0 0.0 None NVEncMode1
I will take a look at rebuilding this when I get a bit of time (and I remember how to do it, this has not changed since 2013)
