Half complete Triac conversion needing some advice.

[Kitwn]

Dan,
The open-collector on the BOB (if that's what the output actually is) is a connection to earth which may be able to control the 24v line directly, though without more knowledge of the exact equipment involved I would not want to suggest you do that without checking with the manufacturer's datasheet. The fact that an open collector does not connect to the BOBs own 5v power rail gives it the flexibility to be used with different voltages from external equipment but without detailed knowledge of your specific equipment caution is advised.

The attached is a possible circuit to try. The 10K resistor pulls the open-collector output of the BOB to +5v when the BOB output is HIGH. This turns on the external transistor pulling the mill input to LOW (about +2v in practice). When the BOB output goes LOW the external transistor is turned off and the 47K resistor pulls the Mill input HIGH. It's primarily the absence of pull-up resistors which has doomed your experiments so far, though there may be one built into the mill input. Try measuring the open circuit voltage at the mill input to find out. If it's 24v then the 47k resistor can be left out. This would effectively give you an external, buffered open collector.

Note that this is an inverting buffer, you may need to adjust settings in MACH3 accordingly (I don't use it so cannot help with where to do that).

Exact resistor values are not critical, the values chosen give about half a milliamp of current in the transistors when turned on.

Kit

Attachment 26325

[Dan-27]

Hello

Thanks for the replies. Kit unfortunately I can't open the attachment, it keeps bringing up an error message that reads 'invalid attachment specified. Would you mind trying to attach it again please?

Thanks

[Kitwn]

OK let's see if this works...