Sending TTL via RS-232 serial port

[Pelle_Pelle]

Hi,

I want to control a stepper motors using the RS-232 serial port. The motor already has a RS-232 to TTL cable adapter. There are 5 inputs and 1 output pins on the DB15 connector. In3(1022)   In5(1) In7(1) In8(1) In9(1) Out6(0). Each of these pin can receive a motion profile command depending if it detect a high or low Signal. My question is how can you send a high or low signal via the serial port. If you need any more information you can check this URL or the motors user manual http://www.excitron.com/Store.asp?m=Excitron&n=14&k=4140&s=Controller+User+Manual&popup=1.

Thank you,

Jean-Félix Péloquin

[Dennis_Knutson]

The document you posted a link to explains how to control a stepper with a communication program like Hyperterminal. To do this in LabVIEW, you use VISA Write to send commands over the serial port. The way I read the manual, you have another 5 input pins and one output. If you also need these pins, then a second serial port could be used for three of them (you only have three outputs on a serial port) or I suppose you could use the parallel port.

[tbob]

Bonjour Jean-Felix.  Since your DB15 has 5 TTL inputs, using the serial port is not a good idea.  You can control the lines on the serial port called DSR, CTS, and CD (or DCD).  As Dennis mentioned, these are only 3 lines.  What exactly does your serial to TTL converter do?  Does it take bit zero from the 8-bit received data and send it to one of the 5 inputs, bit 1 to another, and so on...?  That would be ideal.  If not, I would either use the parallel port, you would have to build your own cable.  There are parallel port examples that come with Labview.  The best solution is to use a DIO board.  You can buy a DIO device that connects to the computer through USB.  These are low cost, about $99.  They provide 24 lines of TTL in and out.  This is more than enough for you to use.  You would still have to build a cable to connect the DIO to the DB15.  There are also DIO boards that plug into a PCI slot inside the computer.  These are more expensive, around $300.  With these, you have to buy a cable and terminal block to make connections to your device.  The USB-DIO is probably the best to use.

[Pelle_Pelle]

Thank you for your answers,

I had just misunderstood the meaning of the 5 "other pins". I Taught It was part of the DB 15  cable. I think I'll be using some kind of cheap DIO board as you suggested since I already own one.

Regards,

Jean-Félix Péloquin

[LV_Pro]

The unit you appear to have, the FTFc15 is controlled by the serial port. The "RS232 to TTL" is just an adapter to change the levels from the "possible" +/-10V of the RS232 spec to a 0 to 5V TTL level. So basically you need to write a driver that converts motion commands in whatever syntax you desire to the command set of the FTFc15 and then use the VISA LabVIEW functions to talk to a serial port to which you have connected the converter.  There is no need to buy a DIO card, it would just make your life very much more complicated. You would then have to write a driver that would convert the FTFc15's (ASCII) commands to serial, send them out over the DIO, etc., with correct timing, etc. Whew that would be a lot of work!Just use VISA, your serial port and the ASCII commands listed in the programmer's manual.

Putnam Monroe
Senior Engineer
North Shore Technology, Inc.

Message Edited by LV_Pro on 07-08-2005 07:48 AM