what is the maximum number of RS232/4 ENET modules that I may configure on my XP machine?

[jcrooke]

My system does not automatically recognize the additional serial ports by attaching ENET RS232/4 boxes to my system.  There are two rs232 ports built into the computer.  These show up in MAX.  Ports 3-6 from my first ENET box show up in MAX.  Ports 7-10 from my second ENET box show up in MAX.  Ports 11-14 from my third ENET box do not show up.  Are they supposed to show up?  Must I do a static configuration? 

[Emilie S.]

Hi jcrooke:

The maximum number of COM ports you can have is operating system dependent.  With Windows XP you should be able to have 256, so you aren't even close to maxing out.  The ports from your third ENET should be showing up.  Is this problem specific to this one box?  If you only have it connected and nothing else, can you configure it so that it shows up?  Are you going through the same configuration procedure for each box?

Emilie S.

[jcrooke]

It is implied from your response that I could configure 63 ENET RS232 devices.  Are you sure that the number of ENET boxes is limited only by the number of serial ports supported by XP?  I would hope that this is the case, but I haven't found a written NI statement about it.

Yes, I used the same procedure for each device.

The static assignment seems to work, but the yellow exclamation points are disconcerting and I would like to know why MAX does not automatically recognize the ports added by my third ENET box.

[Emilie S.]

Hi jcrooke:

I decided to go ahead and set up 3 ENETs here at my desk just to be sure everything should work fine.  I hooked them all up, went into MAX, right clicked Devices and Interfaces, selected to create a new serial ENET device and went through the wizard for all three boxes.  Then after restarting my computer all 12 ports came up in MAX just fine.  What I would suggest at this point is reconfiguring everything.  Is it one particular box that gives you the trouble or is it just which ever box you try to configure last?

What you might want to try to do is delete all three devices you see in MAX, restart the computer, then go in and reconfigure all of them at once.  Then after rebooting, if you still see the problem, you can again delete them and try to set them up one at a time to determine which box isn't functioning properly.

Regards,

Emilie S.

[jcrooke]

Thanks, Emilie. 

Yes, on my machine (Pentium 4 running XP), and perhaps as a matter of general procedure, you have to set them up at the same time. 

I'll explain the error for others who may need this info.  I configured two ENET RS232/4 interface boxes using the NI Serial Device Server Ethernet Device Configuration Utility.  These were assigned ports number 3 through 10 (as verified in the NI Ports control panel .  Ports 1 & 2 were already assigned to the two built-in serial ports on my PC.  This was all fine and good.  I had planned for these ENET devices to be assigned to these port numbers.

At a later time, I set up another ENET 232/4 box.  It was assigned to ports 11 through 14.  I planned for them to be assigned to ports 15 through 18, so I reassigned them using the settings tab of the NI Ports Control Panel.  MAX did not recognize the reassignment.  The ports disappeared and only the two initial ENET boxes showed up in MAX.  I then statically configured these ports to have the desired port assignments (the ones I set up in the NI Ports Control Panel) using MAX and I was able to communicate with my devices using the ports that I had planned for them. 

Soon the network connection was available for a fourth ENET box, which I had planned for ports 11 through 14.  When I ran the configuration utility for it, it was assigned to ports 14 through 17.  I reassigned them, using the configuration utility.  This time, I was a bit more observant.  I noticed that the port assignment actually disappeared, rather than changing to the number that I had chosen.  That is when the AHA! happened.

I removed all of the serial ports using the NI Ports Control Panel.  I also removed the ports from MAX.  After that, I reinstated the serial ports by selecting the devices in the order that I wanted them.  The ports came up in appropriate groups of four with each ENET box servicing the port numbers that I had planned for them.

Jayme