Awareness | Awareness | Open Collector (200 mA) - External Relay Driver Circuit configuration and behavior for QIO-GP8x8
Gain an understanding of the circuit configuration and behavior of an open collector (200mA) external relay driver, specifically for the QIO-GP8x8.
Information
The Open Collector setting in combonation with an external driver circuit is typically used in the following setups:
- To control a device that requires “dry” contact.
- To control a device that requires voltage or current above the capabilities of the Q-SYS device.
- To provide electrical isolation between Q-SYS and an external device.
Considerations for Setup
- Voltage requirements of relay coil?
- Coil current requirement?
- Is relay utilizing Form A, B, or C? (see Common Relay Forms for more info)
Example 1
Lamp 2 On (Relay not energized)
Lamp 1 On (Relay energized)
(DC) Voltmeter across +12VDC and GPIO output pin and ground should measure about 12V.
(DC) Voltmeter across +12VDC and GPIO output pin should measure about 0.6V, meaning current is flowing to ground.
Example 2 - External Coil Voltage
Lamp 2 On (Relay not energized)
Lamp 1 On (Relay energized)
(DC) Voltmeter across GPIO output pin and ground should measure about Vcoil.
(DC) Voltmeter across GPIO output pin should measure about 0.6V, meaning current is flowing to ground.