Kollmorgen Servo Comms...

All this week I've been installing a upgrade to a control system on a labeling machine we built a while back. Part of the upgrade includes replacing the old, discontinued servo drive with a new Kollmorgen SERVOSTAR CD drive. I used one of these drives on another (completely different) machine, and don't remember having any difficulties...

I tried setting up the drive on Thursday, but when I had communication problems, I blamed it on my USB to serial adapter. Today, I borrowed my friend's laptop that has a REAL serial port, but I'm still having the same problem...

I'm using their MotionLink software to setup the drive. The 'scan for drives' function DOES detect the drive, but beyond that, I only get 'unrecognized response' errors when it queries the drive. In 'terminal mode' (and with HyperTerminal), the screen fills with characters. IOW, the drive is sending a continuous stream of gibberish (data?) out the serial port.

I called my Kollmorgen rep. (yes, on a Saturday... he's a good rep.!), but he's not that familiar with this specific drive, so we couldn't figure out what the problem is.

While driving back from the customer, I though of a possible reason why the communication failed. This drive has the RS-232 connections on the standard 2, 3, and 5 pins of the DB-9, but it ALSO has RS-485 connections on the remaining pins. I was using a fully-populated null modem cable to connect to the drive. When I got back to the shop, I dug around in my 'cables' drawer (it's a mess!) and found a null modem cable with ONLY pins 2, 3, and 5 connected. Now that I think about it, I'm pretty sure I made this cable when I set up the Kollmorgen drive on the other machine we built.

The drive's pinout is as follows, compared with a 'standard' serial port:

Kollmorgen Pinout      'Standard' Serial Pinout

 1 - Shield              1 - CD  (Carrier Detect)

 2 - RXD (RS-232)        2 - RXD (Receive)

 3 - TXD (RS-232)        3 - TXD (Transmit)

 4 - Reserved            4 - DTR (Data Terminal Ready)

 5 - Common              5 - GND (System Ground)

 6 - TX+ (RS-485)        6 - DSR (Data Set Ready)

 7 - TX- (RS-485)        7 - RTS (Request to Send)

 8 - RX+ (RS-485)        8 - CTS (Clear to Send)

 9 - RX- (RS-485)        9 - RI  (Ring Indicator)

I won't be back to the customer's facility until Monday, so I can't try the other cable until then. I was just wondering if you guys think this may be the culprit. I'm pretty sure it is, and now I feel stupid for not thinking about the RS-485 connections...

What do you think?...

beerchug

-Eric

Does your friends laptop also have RSLogix/RSLinx Lite on it? Sometimes RSLinx will grab the serial port at startup and you'll go through all sorts of headaches until you uninstall the RSLinx service or un-install the DF-1 Serial driver. I've lost untold hours to this in the past.

Update...

Glad to see SO MANY responses to my question...

As I suspected, the '3 connections only' cable worked just fine, so the drive is now setup...

To add insult to injury, while searching for this thread, I can across THIS post where I already confirmed that my USB adapter worked with this drive...

beerchug

-Eric

P.S. to Norm... Thanks for your suggestion. I know the 'A-B COM port hog' all to well...