RS232 stepper motor control via unipolar drive board

[Sarah_UCL]

Hello all,

I've previously been controlling an RS stepper motor (rswww.com product 440 436) and unipolar drive board (rswww.com product 240 7920) via an NI signal box (CB-50LP, from 1998, not sure if it still exists anywhere else) and a PC card (which connect via a ribbon cable but I don't know the exact name of the connector) using the attached rotation.VI.

I've recently upgraded the PC system to a laptop so I can no longer use the PC card but still need to drive the motors. Having upgraded the system, I'm looking for the cheapest solution possible to send signals to the unipolar drive board. Previously, I was supplying ground, 5V, clock and direction signals.

I've read previous advice on the forums but generally people seem to already have a complete set of hardware and just need help talking to it. From these posts and other searching, I've gathered that my RS232 port (DE-9) is probably the one to use (I also have 1394 and USB free but these seem to give more expensive solutions). From this, I can send ASCII commands through the VISA write Labview function. It looks like I then need something along the lines of an RS232-TTL converter, possibly like this (http://www.digitalnemesis.com/products/rlc1/datasheet.aspx) to convert the signals that I send to the RS232 port to something useful for the drive board. I'm looking to keep the cost under £20 if at all possible.

Am I on the right tracks? If not, can anyone advise the best way for me to 1)make the connection between the laptop and the unipolar drive board and 2) talk to the motor.

Many thanks in advance,

Sarah

[K C]

Hi Sarah,

How many signals do you need ? Only clock and direction and signals back to the PC ?

With a 14C89 you can also convert RS232 to TTL but not from TTL to RS232.

Is the parallel port an option ?

[Sarah_UCL]

Hi KC, thanks for your response. In reply:

"How many signals do you need ? Only clock and direction and signals back to the PC ?"

I only supplied these previously and everything worked so I assume these are all I need.

"With a 14C89 you can also convert RS232 to TTL but not from TTL to RS232."

What is a 14C89? I've not heard of that before.

"Is the parallel port an option ?"

There is no parallel port available, only a serial, firewire or USB port.

[DanBrowne]

Hi Sarah,

As with the previous reply, this sounds like the right direction to go in for your solution, but it would be wise to think about how you're going to get the data back into the serial port.

Regards,

Dan

[K C]

Hi Sarah,

OK, just two signals to drive the motor (Step and direction) and no signals going back to the PC. Also no parallel port.

What you need are two, so called, handshake signals from the RS-232 port to drive the motor. The data out won't do because you cannot control it's level.

The device you mentioned can only drive (and receive) one handshake signal.

With one IC (the 1489 Farnell 1188032) you can convert 4 RS-232 signals to TTL level. But then you have to solder a few things.

Beside that you have to rewire your VI's.

How is this so far ?

[Sarah_UCL]

Hi KC, thanks again.

I'm happy to rewire VIs, I'm fairly familiar with Labview as I've used it a lot for other purposes but just not much for this specific application. I'm also happy to solder things but I'm not so hot with electronics so wouldn't really know where to start with the product you reference.

I assume that I would need to connect the 1489 to an RS232 connector on the one hand, and the unipolar drive board on the other hand?

This sounds like it would be a very cheap solution though!

Sarah

[K C]

I forgot,   you also need 5V power for the IC 1489 (and your motor circuit ?)

Do you have this available ?

[Sarah_UCL]

I could supply 5V from a regulated digital power supply if that is ok?

[K C]

That's OK. I will draw a schematic for your interface.

[K C]

Hi Sarah,

Can you do something with the attached schematic ?