Matrix Orbital GLK24064-25 Legacy - Manual (Page 11)

GLK24064-25 rev. 06 11
2.2.2 Power via RS-232 Connector
Power may be provided to the module by pin 9 of the DB9 connector instead of through the 4-pin SIP. If
power is to be applied using the DB9, it must be a regulated 5Vdc supply*. Since pin 9 is used for the
power source, there must be no connection for RI to the PC. The user must solder the 5 volt jumper point
beside the DB9 connector (see Figure 2-1 for location).
Warning: Use this method of power up at your own risk. Application of a voltage to pin 9 greater
than 5.5volts will cause immediate destruction of unit and void the warranty.
* Note: This applies to wide voltage units (VPT extensions) as well as to standard 5 volt units.
2.3 General Purpose Output
The General Purpose Output is provided to control relays or other devices via the GLK24064-25. This
allows an external device to be turned on or off using your controller and software commands.
The GPO is meant to be used as a pair. The positive side of the GPO is connected to a power source of
+5Vdc supplied by the module. This connection is via a 240 ohm resistor which limits the maximum current
to 20 mA. The negative side of the GPO is connected to ground.
If the device which is being driven by a GPO requires a relatively high current (such as a relay) and has an
internal resistance of its own greater than 250 ohms, then the 240 ohm resistor may be removed and
replaced with a jumper. You will find this resistor directly to the left of the positive pin of the general
purpose output.
Note: This operation requires soldering. With the resistor removed the GPO does not have any over
current or over/under voltage protection so care must be taken when using the GPO. 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
1N4001
Relay
coil
GPO +
GPO -
+
Figure 2-6 Clamping a Relay