Matrix Orbital GLC24064 - Manual (Page 13)

The display will now be in I 2 C mode and have a default slave address of 0x50 unless it has been changed.
Similarly, in order to change the display to TTL mode, simply remove the zero ohm resistors from the 232
or I
2 C jumpers and solder them to the TTL jumpers.
Figure 15: Protocol Select Jumpers
2.4 General Purpose Output
A unique feature of the GLC24064 is the ability to control relays and other external devices using a
General Purpose Output (3), which can provide up to 20 mA of current and +5Vdc from the positive side of
the GPO. This is limited by a 240 ohm resistor which is located directly above the positive pin as pictured
below in
figure 16 . If the device, which is being driven by a GPO, requires a relatively high current (such as
a relay) and has an internal resistance of its own greater than 250 ohms, then the 240 ohm resistor may be
removed and replaced with a Jumper.
Pin 1 - GND
Pin 2 + MAX: 20 mA, +5Vdc
Figure 16: General Purpose Output
WARNING If connecting a relay, be sure that it is fully clamped using
a diode and capacitor in order to absorb any electro-motive force (EMF)
which will be generated.
Matrix Orbital GLC24064 8