How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask OSXpert Your Own Question

OSXpert
OSXpert, Mac Software Engineer
Category: Mac
Satisfied Customers: 226
Experience:  2 years as a geek squad computer technician, 5 years as a software engineer and unix systems admin
50723742
Type Your Mac Question Here...
OSXpert is online now
A new question is answered every 9 seconds

Is anyone out there an expert on driving serial devices via

Customer Question

Is anyone out there an expert on driving serial devices via a USB-serial convertor from a Mac (OSX 10.6.2)? I need an ubergeek/guru!
Thanks!

More detailed information:
I am trying to drive a serial device from my MacBook Pro. The relevant components are:

1) MacBook Pro running OSX10.6.2

2) USB to serial convertor; unbranded, but the driver has been installed and, as per the instruction manual, the extension "ProlificUsbSerial" appears under system profiler.

3) RS232 to RS484 convertor. This was supplied with the equipment I am trying to drive (its part number is XXXXX 8722)

4) Cable

5) Serial device. It is a 3-axis picomotor controller (New Focus model 8753) intended to be serially controlled. The cable is plugged into its "Network In" socket.


Software: the intrument supplier (New Focus) provided a LabView vi intended to drive this device. However, I presume it was intended for a PC. I am running LabView 2010, and can open the vi without problems.

The Problem:
I don't seem to be talking to the device. I get various error messages, and my suspicion is that I am doing something simple yet dumb. NOTE: if I go into system preferences/network, I can see "USB-Serial Controller D" and also "USB-Serial Controller D2" (I had previously tried installing another USB-to-serial convertor). In both cases, their Status is "Not Configured"

Any advice appreciated!
Thanks!
Paul
Submitted: 5 years ago.
Category: Mac
Expert:  OSXpert replied 5 years ago.

OSXpert :

see if it responds

Customer :

Did I miss the start of your answer? I just got "see if it responds"...

OSXpert :

Yes, I recommend start with ZTerm, are you familiar?

Customer :

Hi - sorry, getting coffee. Not familiar with ZTerm; I have "Terminal", if that's any help?

OSXpert :

This is probably going to get pretty technical -- are you familiar with the command line (Terminal)?

Customer :

A little. Let's give it a go...just be gentle!

OSXpert :

Alrighty, I only have a few minutes, but we'll see what we can get done...

OSXpert :

first, lets get ZTerm...also, what is the device you are connecting?

Customer :

The device (this won't make you happy!) is a 3-axis picomotor driver - NewFocus 8753. I'm guessing this is not very helpful!

OSXpert :

k..robotics I take it?

Customer :

Yep. The device is meant to be controlled serially, and I have a LabView VI to drive it, from the supplier, but I guess it was written for PC. I can open the VI in LabView on my Mac, but it doesn't talk to the device. I'm assuming it's a basic problem with configuring the serial ports. Also, I've downloaded ZTerm - can start any time.

OSXpert :

get ZTerm here http://homepage.mac.com/dalverson/zterm/

Customer :

Already got it - it's now in my Applications folder.

OSXpert :

k, run it

OSXpert :

This is going to be tricky because I don't have a serial device plugged in, so I can't see what you see

OSXpert :

but, when you open it, you should be prompted to select a device, select your USB-Serial converter

Customer :

I started Zterm. Window comes up "Error: 2 opening port". An error window also comes up, " is not available. PLease select another port", and "Serial Port:" followed by a pulldown menu which currently says "usbserial"

Customer :

(Menu options are:


usbserial


PL2303-00002006


Bluetooth-PDA-Sync


Bluetooth-Modem


SGH-G600-SerialPort)

OSXpert :

so...the usbserial device threw the errors?

Customer :

I presume so. All I know is what I'm seeing...

Customer :

(NB - USB-serial convertor is plugged in at the moment)

OSXpert :

k, try selecting the SGH-G600 device

Customer :

OK - (SGH-G600 is my phone). I get same error message in the window (except now "Error: 16 opening port"), and error window "SGH-G600-SerialPort is not available. Please select etc."

Customer :

(NB - the phone itself isn't here, if that's relevant...)

OSXpert :

hmmm, sounds like the driver isn't installed correctly. Are you sure the driver is on there?

Customer :

For the USB-serial convertor, or for the SGH-G600?

OSXpert :

let's just focus on the USB serial converter for now

OSXpert :

unplug the other

Customer :

The installation of the convertor driver went OK, and there's the extension "ProlificUsbSerial", when I look using System Profiler - like the installation instructions said there should be.

OSXpert :

Well, without being in front of your system, it's going to be tough for me to figure out whats wrong. Serial over USB can be a big pain -- I would almost recommend buying an old junk laptop from craigslist and installing Linux...I may have to opt-out and see if another expert will pick this up.

Customer :

Yeah, but I'm kinda stuck on Mac (this thing is part of a huge system). But I did just find a forum thread indicating all kinds of problems with Prolific convertors. Any recommendations on an alternative?

OSXpert :

let me see if there is one from FTDI for mac, hang on...

Customer :

:-)

OSXpert :

you need to go USB->RS232->RS484?

Customer :

Apparently so. I have a 232>484 convertor provided by the device supplier...

OSXpert :

are you sure the motor your controlling needs to be done via RS484?

Customer :

Not absolutely sure, but it came with the device, and the 232>484 convertor was being used previously when the system was on a serial port from a PC.

OSXpert :

okay -- and that was working?

Customer :

It was. Sadly, due to an *ahem* administrative error, the PC and the software on it is now in landfill (not my fault!). And other things now mean I need to transplant to Mac anyway.

OSXpert :

bummer, let me see if I can dig something up...

Customer :

You're a hero. :-)

OSXpert :

thanks :)

OSXpert :

try this for starters...

OSXpert :

http://www.bhphotovideo.com/c/product/382968-REG/Keyspan_USA19HS_USA19HS_USB_to_Serial.html

OSXpert :

that will get you to RS232

OSXpert :

still trying to find another conversion to 484

Customer :

Ok :-)

Customer :

At the moment, I'd be happy to get any kind of signal out of my Mac :-)

OSXpert :

yeah, I understand that

Customer :

Ah - just checked the device suppliers site - they say it's controlled "


(using DLL functions and an RS-232 to RS-485 adapter)" (sorry - 485, not 484 as I'd said)

OSXpert :

You can also buy a null modem, and use it to ensure your USB-232 connections are functioning...

OSXpert :

http://www.tripplite.com/en/products/model.cfm?txtSeriesID=777&txtModelID=2261

OSXpert :

wait, might have something good here

OSXpert :

you might want to try going directly from USB to RS485...

Customer :

OK - that could be useful. So, if I understand correctly, my first action should be to get a Keyspan USB>RS232 convertor; see if it works in Zterm; check if it works on the null modem, and then see if things downstream work?

Customer :

(ah - just saw your latest - USB to RS485?

OSXpert :

yeah, let's try that -- I think it would be worth the $40 and it will reduce the complexity of your setup.

OSXpert :

http://www.rs232-converters.com/single_usb_to_rs485_converter.htm

Customer :

Anything's worth it if it helps solve the problem. I'll need to see if I can get it in the UK, but should be able to.

OSXpert :

Try that to begin with, I think it's a good start to things

Customer :

OK - it also says it uses the FTDI chipset which, according to the forum, is better than the chipset in the 232 convertor I have at the moment. I'll give it a go. Many thanks for the advice - I'll click the "Accept" button when we're done.

OSXpert :

Good deal, I have used FTDI in the past with a few different serial devices. I have always had good luck with them

Customer :

OK- here's hoping. I presume I terminate things here when I click "Accept"?

OSXpert :

Yes, it will close this session. If you want to get the new adapter, you can send additional questions to me directly by clicking my profile name

OSXpert :

If you need more info before accepting, please ask. I want to make sure you get the service you need

Customer :

OK - you mean "OSXpert"? And I think I've got my $36 worth - there's an hour of your life you won't get back again :-)

OSXpert :

haha, true :) Yes, you can click OSXpert to send questions to me directly

Customer :

Magic - thanks. I'll leave you to enjoy the rest of your day, and I'll track you down if I need another answer.

OSXpert :

Sounds good. Enjoy your (evening?). I guess it's 9:15 in the UK

OSXpert :

and thanks for your patience

Customer :

Yeah, about 9:15. I hear a bottle of wine calling me from the fridge. Thanks for your help, and have a good day over there.

OSXpert :

Thanks, XXXXX XXXXX wine and your Sunday. Have a good one

OSXpert and other Mac Specialists are ready to help you