relay activation using rs 23

[satyarajasekhar]

Is there any low cost board in which a relay can be activated through labview with rs 232 as communication. please let me know as soon as possible.

i need to acivate a relay of 5V with a timer from labview and it should be communicated through rs 232 to the relay board.

[sebster · Accepted solution]

Are you looking to switch your relay specifically with RS232, or just by using the serial port?

If it's the latter, then take a look at the 'Troubleshooting Serial Line Monitor.vi' in the LabVIEW examples. With this you can control the DTR (pin 4) and RTS (pin 7) lines of your serial port and use these to switch a transistor or FET to control your relay.

[satyarajasekhar]

Thanks for the reply,

can we control multipler relays say 4 no's at different intervals using one serial port??

if so please let me know.

Thanks and regards,

Rajasekhar

[sebster]

Well, that's a different question. Originally you asked "i need to acivate a relay of 5V..." so the method described would work.

You should be able to control 2 relays from one port, one from each of the DTR and RTS.

To control more would need to go for the relay card (or add more serial ports??)

[Dennis_Knutson]

You should be aware that RS-232 voltage levels are +/- 3 to +/- 15. What might work on one pc might not work on another. A simple Google search for 'RS232 Z Relay Board' returns numerous results. You should have done that search before posting your question.