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OPP coils / drivers

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There are a few things to know about controlling drivers and coils with OPP hardware.

Warning

Please ensure that you have established common ground between logic and coil power before turning on high voltage on your coils (especially on homebrew machines). Ignoring this might lock on your coils, overheat them, burn down your house or kill you. We are serious, floating grounds are dangerous. If you are not an electrical engineer read the guide about voltages and power.

In a nutshell: You need to connect your logic ground (5V/12V) and your high voltage ground (48V or 80V). A power entry or power filter board is a convenient solution to solve this (and more) issues.

Always turn all PSUs off when connecting power or you might fry all boards at once. This is generally a good idea but even more important when connecting more than one power supply to a board.

IF YOU DID NOT UNDERSTAND WHAT THIS WARNING MEANS STOP NOW AND TRY TO UNDERSTAND IT. OTHERWISE YOUR HARDWARE WILL LIKELY BURST INTO FLAMES AND YOU NEED TO WAIT A FEW DAYS FOR A REPLACEMENT OR EVEN WORSE IT MIGHT KILL YOU. IGNORING THIS IS THE MOST COMMON CAUSE FOR BROKEN DRIVER BOARDS.

Number

OPP coils are numbered sequentially depending on which wing board is the coil output. Wing position 0 contains coil numbers 0 to 3. Wing position 1 contains coil numbers 4 to 7. Wing position 2 contains coil numbers 8 to 11. Wing position 3 contains coil numbers 12 to 15. The coil is numbered using the position of the OPP card (starting at 0), then a '-', and finally the coil number on the card.

coils:
  some_coil:
    number: 0-12

The above example configures a coil output as the first OPP card, and the third wing board, first output. On the microprocessor card, the output is marked as 3.4 (wing port 3, position 4).

Pulse time

The OPP hardware also has the ability to specify the "pulse time". Pulse time is the coil's initial kick time. For example, consider the following configuration:

coils:
  some_coil:
    number: 0-12
    default_pulse_ms: 30

When MPF sends this coil a pulse command, the coil will be fired for 30ms.

Hold Power

If you want to hold a driver on at less than full power, MPF does this by using default_hold_power parameter which works for all platforms. It can range from 0.0 to 1.0 and defines the time share the coil is on (0%-100%).

The period is fixed at 16ms for OPP. To set the hold power to 25%, set default_hold_power to .25 and OPP will use 4ms/16ms = 25%.

coils:
  some_coil:
    number: 0-3
    default_pulse_ms: 32
    default_hold_power: 0.5

This will configure OPP card 0, solenoid wing 0, last solenoid to have an initial pulse of 32 ms, and then be held on at 50% power.

Pulse Power

Note

This feature is only available on OPP firmware version 2.3.0.5 and above.

If you want to pulse a driver on at less than full power, MPF does this by using default_pulse_power parameter. This can be used along with default_pulse_ms to fully tune the response of a coil. This can be especially useful when controlling lower voltage coils from a 48V source.

It can range from 0.0 to 1.0 and defines the time share the coil is on (0%-100%). Any value under 0.03125 will be forced to output 3.125%.

coils:
  some_coil:
    number: 0-3
    default_pulse_ms: 32
    default_pulse_power: 0.8125
    default_hold_power: 0.125

This will configure OPP card 0, solenoid wing 0, last solenoid to have an initial pulse of 32 ms at 81.25% power, and then be held on at 12.5% power.

Recycle Factor

OPP allows you to fine tune the recycle time of your coils. If you add recycle: True to your coil you can set recycle_factor in the platform_settings secton of your coil to set the recycle time. The time will be default_pulse_ms * recycle_factor. For instance, if you set a pulse time of 10ms and a recycle_factor of two the coil will cool down for at least 20ms. This is an example:

coils:
  some_coil:
    number: 0-3
    default_pulse_ms: 10
    default_recycle: true
    platform_settings:
      recycle_factor: 2

What if it did not work?

Have a look at our OPP troubleshooting guide.

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