Matrix Orbital GLK12232-25-WBL - Manual (Page 12)

Figure 4: Using the General Purpose Outputs
If the device which is being driven by a GPO requires a relatively high current (such as a relay) it must
have an internal resistance greater than 250 ohms, or must be current limited to 20 mA by means of a suitable
resistor.
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).
Figure 5: Clamping a Relay
3 Displaying Text
This chapter describes the various text-display commands in detail.
3.1 General
Text is displayed on the display using fonts saved in its internal flash memory. The display is supplied
with a 5x7 font installed. If this is suitable, there will be no need to install any other fonts.
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