User guide

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

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