Matrix Orbital VK162-12 Legacy - Manual (Page 16)

Table 5: Connector Pinout
Pin 4 Ground
Pin 3 SDA (I 2 C data)
Pin 2 SCL (I 2 C clock)
Pin 1 Vdc
2.2 General Purpose Outputs
The display has seven general purpose outputs. These are provided to control relays or other electronic
devices. This allows external devices to be turned on or off using the PC or controller and software com-
mands. The + terminal is connected directly to the module positive supply, the - terminal is connected
through a 240ohm current limiting resistor and the electronic switch to ground.
Figure 16: General Purpose Outputs
Maximum allowable current is 20mA, which is enforced by the current limiting resistor. If the device
being switched has a resistance of 240ohms or more the corresponding resistor may be shorted.
NOTE The GPOs do not have any over current or over / under voltage protection so
care must be taken when using them. For instance if the external device is a relay it must
be fully clamped using a diode and capacitor to absorb any generated back electro-motive
force (EMF).
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