7i76E + THCad 10V

The unipolar/bipolar jumper on the THCAD has nothing to do with the encoder interface
it determines if the input voltage range is bipolar (-5 --> +5 ) or unipolar ( 0--> 10 )
(you want unipolar)

If the THCAD is jumpered for bipolar mode you would expect around 16 KHz at 0V
when the 1/32 output frequency option is selected

The reason you cannot count the output frequency correctly at 1:1 is likely that you have the input filter enabled
on the encoder so it cannot count single 1 usec pulses (you can turn this off in hal)

EDIT pulse width at 1:1 is approximately 0.5 usec, too fast for the encoder if the filter option is enabled
in the hal file

Thanks for the prompt reply,

It seems strange because I have connected to Hypertherm PM65 remote control cable, and according to Hypertherm it's unipolar...
anway I'll investigate this more deep..

Now I'd like to increase the precision of the counts, so would like to clarify where the filter settings appeared in my config.
From the first look I definitelly have no such explicit setting in the configs, but it might be caused by other settings I believe. Could you check my config if I have them to get rid and try to use 1:1 divider?

at first my servo period is:
SERVO_PERIOD = 1000000

hostmot 2 driver config:
loadrt hm2_eth board_ip="10.10.10.10" config="firmware=hm2/7i76/7i76e.BIT num_encoders=1 num_stepgens=3 sserial_port_0=20xxxx"

then I have couple lines which was in scratch file and I have just left them there:

setp hm2_7i76e.0.watchdog.timeout_ns 5000000
...
# latch 50 usec before nominal read time:
setp hm2_7i76e.0.dpll.01.timer-us -50
setp hm2_7i76e.0.stepgen.timer-number 1

and the only lines related to the encoder config are:
# Set up the Encoder for the THC
setp hm2_[HOSTMOT2](BOARD).0.encoder.00.counter-mode 1

full config files are in the attachment

The encoder filter is part of the hostmot2 encoder.
linuxcnc.org/docs/2.7/html/man/man9/hostmot2.9.html#encoder

JT
mesaus.com/

If you want to improve the resolution, you can install the lowpass filter component
and filter the encoder velocity output, this will not improve the precision however.


If you want to count at 1:1 you will have to turn off the encoder noise filter,
but I suggest you do not do this but use the 1:32 ratio, for two reasons:

1. The resolution will remain the same (about 10 bits at 1 KHz)
2. You will have improved noise immunity by leaving the encoder noise filter on

well, it explains a lot of "magic" parameters in my config file )))
I'd like to clarify if the .counter-mode=1 (step/dir mode) is the best to work with the TCH card?

thank you in advance,
Oleg

The standard encoder counter only has 2 counter modes: quadrature and step/dir

only step/dir (counter mode 1) will work with the THCAD