Matrix Orbital PK162-12 - Manual (Page 16)

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).
Figure 17: Clamping a Relay
3 Displaying Text
This chapter describes the various text display commands in detail. Before issuing commands to the
PK162-12 please read sections 7.2 and 7.3.
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