General
The CENTAURI II has got two GPIO interfaces (GPIO = General Purpose Input/Output):
| • | TTL I/O The TTL I/O uses a DB25 female port. |
| • | Opto Input Relay Output (optional) The Opto Input Relay Output uses a DB 37 female port. |
The GPIO feature of CENTAURI can be used in two different ways:
| • | Far end switching The states of the inputs (i.e low or high) are transmitted to outputs of the other side CENTAURI. The transmission of these states is done inside of the ancillary data transport. This feature enables to switch on/off far end devices, LEDs etc. |
| • | Event Action Programming One of the powerful features of CENTAURI is the event action programming. The event action programming allows the enhanced (!) user to adapt the CENTAURI to his/her needs. How event action works is generally described in application note 4 on Mayah Website (www.mayah.com/content/download/pdfs/appnotes/centauri/a_n_e_004.pdf). The GPIO interfaces can also be used in event action programming. For instance it is possible to control special functionality of CENTAURI just by open or close external switches. A good example for this is described in application note 3 on Mayah Website (www.mayah.com/content/download/pdfs/appnotes/centauri/a_n_e_003.pdf). |
All the GPIO outputs can be set with the CENTAURI command ‘TTL_IO’. The direct commands of CENTAURI are described in the Communication Reference Manual (www.mayah.com/content/download/pdfs/manuals/communication-reference_man.pdf).
Differences of the GPIO interfaces
The TTL I/O interface has got 5 inputs and 5 outputs. Its pin layout is described in the CENTAURI Interface Manual (link at www.mayah.com/content/download/pdfs/manuals/centauri-interface_eng.pdf).
The Opto Input Relay Output interface has got 8 inputs and 8 outputs. Its pin layout is shown below.
There are three good reasons for using the optional Opto Input Relay Output card:
| • | 8 additional inputs and outputs are available for event action programming and far end switching |
| • | The relays are capable of switching much higher loads (1A at 24V) than the TTL outputs which can sink only 4 mA or source just 1 mA |
| • | Opto inputs and relay outputs are potential-free |
Pin layout of 
Opto Input Relay Output interface:
Simple schematic how Opto Input works:
