Appendix 4: GPIO Connection

GPIO Output Connection

The 4 outputs are configured as "open drain," enabling direct connection to energize external relays, lamps, or other DC devices.

The maximum supply voltage is 36 volts, with a maximum load current of 500mA.

It is recommended to use 20-24 AWG wire gauge with the connector. Please note that the OUT GND connection is linked to the CTM-500's supply ground.

Open

GPIO Input Connection

The 4 inputs on the CTM-500 can be configured for monitoring either a digital DC voltage state or an analog DC voltage. All inputs are single-ended.

For digital state monitoring, the input voltage range is 0-36 volts. The threshold detection voltage is set at 2.5 volts with 1 volt of hysteresis. Please note that the IN GND connection is referenced to the CTM-500’s supply ground.

Analog input values are sampled and can be reported at a maximum frequency of 10Hz.

Example of Digital Input wiring

Open

For analog voltage monitoring, the measurement range is 0 to +10 volts with a resolution of 10mV. The input can tolerate voltages up to 36 volts. Please note that the IN GND connection is referenced to the CTM-500’s supply ground.

Example of Single Ended Analog Input Wiring