How Mode Arcline works, with waveform scoped. (brief strobing)

Mode Arcline is a relatively vintage lighting effect which is still available for hire from some companies, but should be installed with the full understanding that it uses a connector in a non compliant manner and could pose a significant shock risk if a grounded appliance is plugged into what appears to be a normal IEC socket. Non-standard use of connectors was rife in the early days of similar equipment and a certain grandfathering element has to be taken into account, and equipment like this only used by electrically competent people.

I fluffed the description of the output reset diode a bit. As soon as a high reset pulse is applied to the 4017 it will instantly be shunted by output 4 going low via the diode, meaning that the reset pulse only lasts as long as is needed to reset the chip to the first output (output zero).
The way the incoming pulses are filtered and then fully restored with new clean pulses on the output of each section makes the system very robust against external electrical interference. The use of four core cable for long runs between controller and tubes is to separate the power negative from the circuit negative so that the first tube in the run doesn't see rogue control glitches due to current spikes on the power causing misinterpretation of signals on the control line. The separate control negative carries no real current and will result in a cleaner 0v/control reference.

I've built the simple switched DMX interface box in a "Lego" style so that the same box can be used for other purposes in the future if required.

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