RUT240 Pin 4 Output issue

I have built a circuit using pin 4 of the rut240 to energise a IXYS CPC1017 relay, to reset an application server. Following the basic wiring diagram ( RUT240 Relay to Open Collector Output - Teltonika Networks Wiki )

I use a 1.5k resistor on Pin4 to regulate the voltage to the relay chip, I have also a 10k pullup to the +Vdc. This all works fine, turning on and off, or pulsing as requried. However, when turning on power to the RUT240 to strart its boot process, the relay is momentarily energized (for a few ms). This does not occur if the RUT240 does a reboot.

I would have thought - even if the the output did not have an internal pullup the the 10k pullup normally would do the job.

Any ideas appreciated?


We’ve not experienced such behavior with the RUT240, so I believe the issue might be within your setup. Firstly, I’d suggest updating to the latest firmware, as that could contain some improvements. Secondly, please provide your wiring diagram, with the voltages at each connection. This will help us understand your configuration and hopefully determine where the issue lies.
Finally, does this issue only occur from a reboot, or does it also get energized during a “cold” boot?
Make sure to pay attention to the note provided in the Wiki article:

if you use different power supplies for RUT240 and relay, their ground wires must be connected together.

Best regards,

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