Matrix Orbital GLK12232-25-SM Legacy - Manual (Page 14)

The two outputs differ slightly in specification;
• G1 provides an output which is switched LOW when ON. When G1 is OFF it is pulled up to +5V
through 150 kohms. In other words it can only be used to ’ground’ an external device. Maximum
current is 250 mA.
• G2 provides an output which is switched LOW when ON. When G2 is OFF it is pulled up to +5V,
supplied by the module. Maximum current is 250 mA.
GPO1
GND GND GPO2
Figure 9: GPO Configuration
Both outputs are referenced to ground. 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 100 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 10: Clamping a Relay
Matrix Orbital GLK12232-25-SM 10