Matrix Orbital LK162-12 Legacy - Manual (Page 12)

LK162-12 rev 4 12
For more information on Phillips I
2 C please visit…
http://www.ping.be/~ping0751/i2cfaq/i2cindex.htm
2.2 General Purpose Outputs
The LK162-12 has seven general purpose outputs. These are provided to control relays or other electronic
devices. This allows external devices to be turned on or off using your PC or controller and software
commands. (See sections 6.1.7 and 6.1.8 for the command syntax.)
Each output is wired as shown in Figure 2-8. The + terminal is connected directly to the module positive
supply, the – terminal is connected through a 240 ohm current limiting resistor and the electronic switch to
ground.
Figure 2-8 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 240 ohms 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).
10 - 100 uF
1N400 1
Relay
coil
GPO
+ -
Figure 2-9 Clamping a Relay