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Limitimer integration

clock-8001 supports acting as a display for limitimer controllers or acting as a controller for limitimer display units. This functionality requires additional hardware.

Requirements

Hardware

The limitimer functionality requires an RS-485 adapter and a wiring adapter. For raspberry pi a RS-485 hat, like the waveshare rs-485 + can hat, is recommended. Any hat that uses the UART provided on the gpio header should work. Most USB rs-485 dongles can also be made to work, but doing so will require loading the kernel modules for it.

For raspberry pi hats the serial device to use is /dev/ttyAMA0

Wiring

The complete RS-485 differential pair signal is only available on the rj-45 (ethernet) connectors from limitimer. The pinout of the connector is as follows:

  1. +12V
  2. B (D-)
  3. A (D+)
  4. GND
  5. GND
  6. A (D+)
  7. B (D-)
  8. +12V

With T-568 A colors:

  • Orange + orange/white to A
  • Green + brown/white to B.
  • Brown + green/white to +12V
  • Blue + blue/white to GND

Or with T-568 B:

  • Green + green/white to A
  • Orange + brown/white to B.
  • Brown + orange/white to +12V
  • Blue + blue/white to GND

The XLR pinout is:

  1. +12V
  2. GND
  3. B (D-)

It is recommended to use continuity tester while building the adapter and check that the signals aren't shorted and that the 3 common signals from the ethernet and XLR connection match before turning the system on.

RS-485 line termination resistors

RS-485 spesification requires 120 ohm termination resistors at the ends of the bus. This is simply just a resistor between A and B lines. DSAN has done some additional engineering in their RS-485 receivers and limitimer itself doesn't require the terminators, but many RS-485 receivers will need them. Usually two devices on the bus is fine no matter what the devices are without termination, but after that the clock-8001 might not be able to send or receive to limitimer units without at least one end of the chain having the 120 ohm terminator resistor.

Limitimer display settings when controlled by clock-8001

If you use clock-8001 to contorl limitimer display units you need to set their count direction to down on the dip switches. Other switches can be set based on desired behaviour.

Controlling limitimer displays with clock-8001

Enable sending of data to limitimer displays on the clock config. After that timers 1-4 will be sent as limitimer programs 1-4. The first running timer of them will be sent as the "active" limitimer program.

Configure the display unit dip switches to receive the timer you want on it.

Using clock-8001 as limitimer display

Enable receiving of limitimer data in the config. This will cause timers 1-5 to be set based on received limitimer state. Timers 1-4 are the programs 1-4 from limitimer and timer 5 is the currently selected active program from the limitimer controller.

Set the clock-8001 overtime config as desired.

Currently limitimer beeping behaviour isn't implemented.