Hi
I have a weatherstation with a CR1000 where C-ports are used like this
C1 - SDI12 sensor
C2 - control modem on/off
C3 - control web camera on/off
So far so good
now I like to add
COM3 - RS232 snow depth sonar
COM4 - RS232 water level sonar
I need too more controls for the sonar sensors, one can use C4 but there is lack of one control.
I don't like to use a SDM expansion peripheral for just one port, there is not enough space either.
I am wondering if I could use a excite port like VX3 together with an external logic level shifter.
Could anybody share experience with that?
Best
Uta
Hi
is the sw12 terminal already used? otherwise you can control ON-OFF of the modem or camera.
With the VX3 you could control a bistable relay, perhaps with a small transistor circuit. But for security you should check the actual On-Off status with an analog channel. If you use the 12V you should divide by 3 before using an analogue channel (5000mV max).
I think you already know, but the excitation channels remain high only during the measurement / supply, so give a pulse and the relay changes position, for various reasons you may not be sure of what condition you go to change then with an analog channel you might have certainty of how is the output of relay it is and you consequently behave.
Smile
The SW12 is already in use, but I can check if that is really needed.
The RS232-connector could probably be used if I connect the modem via CS I/O but I prefer to have identical COM-ports for the sonar sensors.
Thanks for your information on the VX3, I need to check that better.