Hi Bruno,
the Monarco HAT has hardware PWM and therefore does not need to create PWM in software using a PWM block. Documentation to the PWM on Monarco HAT can be found on page 16 in Monarco technical specification https://www.monarco.io/docs/Monarco-HAT-Hardware-Reference-Manual.pdf.
All you need to do is set the PWM frequency (in your case to 50 Hz) and calculate the actual duty cycle for one channel according to the equation:

Duty_cycle = pulse_width/period_length

Take a look at example 0121-05_Monarco_HAT_PWM_output to find out how to set the frequency and duty cycle for PWM1 (for example).

Hope, this will be helpfull.
Cheers
Jan.

@reitinge To be more specific, for an open-drain digital output you will need to subtract the calculated duty cycle value from 1:

Duty_cycle = 1 - Calculated_duty_cycle

For 1 ms width pulse and frequency 50 Hz:

Duty_cycle = 1 - 0.05 = 0.95

For 2ms width pulse and frequency 50 Hz:

Duty_cycle = 1 - 0.1 = 0.90

If you are using a DO as an 5V voltage source, see the Using digital outputs in 5V logic circuits chapter here:
https://support.monarco.io/help/digital-outputs-of-the-monarco-hat
The logic is "reversed":
If DOUT=OFF, no connection to ground exists and you will measure 5V at the output. If DOUT=ON, connection to ground is made and there will be 0V at the output. That's how you can control devices which use 5V logic.

I apologize for the mystification in previous posts.

Hi Bruno,
I have connected my Monarco HAT to the oscilloscope and the PWM behaves as expected. I set the frequency to 50 Hz and on the first measurement I set the duty cycle to 0.5 (Figure 1). Figure 2 shows the measurement at a duty cycle = 0.1. Please note that Monarco HAT has open-drain outputs, as shown in Figure 2.


Can you send a wiring diagram to your RC servo?

The length of the period for 50 Hz is 0.02 s.
For pulse width 0.001 s:
Duty cycle = 0.001/0.02 = 0.05
Pulse width 0.002 s:
Duty cycle = 0.002/0:02 = 0.1

Are you sure about the frequency and width of the pulses? I would expect a duty cycle range from 0 to 1.

Hi Bruno,
the Monarco HAT has hardware PWM and therefore does not need to create PWM in software using a PWM block. Documentation to the PWM on Monarco HAT can be found on page 16 in Monarco technical specification https://www.monarco.io/docs/Monarco-HAT-Hardware-Reference-Manual.pdf.
All you need to do is set the PWM frequency (in your case to 50 Hz) and calculate the actual duty cycle for one channel according to the equation:

Duty_cycle = pulse_width/period_length

Take a look at example 0121-05_Monarco_HAT_PWM_output to find out how to set the frequency and duty cycle for PWM1 (for example).

Hope, this will be helpfull.
Cheers
Jan.

You're welcome Mike. Good luck with your project.

Cheers
Jan

You're welcome, Mike.
The Python block must be checked when installing Rexygen Studio (it is not part of the default installation).

Cheers
Jan

Hi Mike,
string change checking can be easily done in a Python block:
https://www.rexygen.com/doc/ENGLISH/MANUALS/BRef/PYTHON.html
You can compare the previous value of a string input with the current one, and if the values ​​differ, you can set the logical output to true and connect that output to the ARS:run input.

There is probably other solution with the String blocks:
https://www.rexygen.com/doc/ENGLISH/MANUALS/BRef/BRef_ENGch11.html
and Logic control blocks:
https://www.rexygen.com/doc/ENGLISH/MANUALS/BRef/BRef_ENGch8.html
but the solution using a Python block is easier for me personally.

Hi Mike,
it looks everything is fine according to the log and the error is somewhere else. If you update Raspberry to Buster, we will not have to deal with the problems caused by the incompatibility with the Raspbian Stretch that is considered as unsupported.

I've consulted your issue with DWM developers and they advised me on a few things you can try:

• Please, send me the log after command

sudo systemctl status systemd-resolved

• Verify the correct installation of RexArc using:

RexArc -h

• The developers strongly recommend that you start using the Buster release. Currently, testing on Stretch is minimal. Do you have a special reason for using Stretch?

Kind regards
Jan

Hi Mike,
you don't need any special license for DWM yet. It's look to me that you have a problem with DNS server. Is that possible? Please take a look at /etc/systemd/network/eth0.network once again and set Gateway and DNS if you didn't that before.
https://wiki.archlinux.org/index.php/systemd-networkd#Wired_adapter_using_a_static_IP

I've only tested DWM with Buster so far. I'll try it again with Stretch.