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Bill Smith

Default Ethernet Ports

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I just received two brand new V350s and am trying to connect over ethernet. New laptops no longer have serial ports built-in (well most, anyway) and I left my USB-serial adapter at work. But no luck over ethernet - doing some troubleshooting:

1. Set default IP address in Info Mode and set my PC to a compatible address

Wireshark packet sniffer - I see a TCP SYN packet to the unit at port 20256 but the response is TCP RST. This tells me that the unit is there - I already knew that because ping was successful - but it's not listening on the required port. BRAND NEW out of the box - and I can't connect with the programming software, which I just downloaded the latest version.

Info Mode - looking at info mode, I can view the port setup for ethernet (great feature, by the way). My 4 sockets, right out of the box:

Transport protocol / socket

UNIT 1

0. UDP / 54208

1. UDP / 14246

2. UDP / 16545

3. UDP / 31779

UNIT 2

0. UDP / 64486

1. UDP / 54251

2. UDP / 2504

3. UDP / 26629

Well, it's clear Visilogic will fail to connect to the unit because none of the four sockets are listening on TCP port 20256. The ports look random. Set one of the ports to TCP Slave with number 20256 and I am able to connect and download, after looking up the default ID.

Help file V300-21-G23 Rev 3.00: default socket configuration is as follows -

0. UDP / 20000

1. TCP / 20256

2. TCP / 502

3. TCP / 20257

Well, thats it. You deliver product not in compliance with your documentation so that users can't connect to it out of the box. Is this a manufacturing problem that the default ports are not getting set correctly?

I wondered if it is an issue that the first download sets the default sockets, but for me then that is a chicken-and-egg scenario. I need to connect - to set the defaults - to allow me to connect... you get the idea.

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You won't be able to connect to it until you put a ladder program in via the serial port that initializes the Ethernet port and gives the PLC a name. You then need to know both the IP and the PLC's name to connect via Ethernet. This is done for security reasons; you don't want just anyone logging into the PLC over the network.

Joe T.

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Hi,

Actually there is an option to establish connection with the PLC via Ethernet even if you did not configure PLC name and TCP/IP card init in the ladder code.

The way to do it is as follows:

  • Go into info mode --> Ethernet settings
  • Set IP address,subnet mask and default gateway to match your network settings.
  • Set one of the sockets to TCP slave with port number 20256. (Basically you can set other port number)
  • Then check in info mode --> Operands --> system double words --> the value of SDW9
  • From VisiLogic or other Unitronics software set in the connection parameters: IP address of the PLC, TCP port and the PLC name (SDW9 value)
  • Now you should be able to connect.

Bill: For investigating this issue with the "strange" port numbers which you got by default - please send us the serial numbers of those PLCs.

Thanks.

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Joe,

Unless my units are defective, your not technically correct. If you read my post, you can see that adjusting (all in info mode):

1. Transport protocol

2. Port number

2. IP

3. Looking up default PLC name

then connection can be made. As described, I was then able to to download. My issue was not to gain connection - it is why out-of-the-box we can't, when it is only a settings issue that does not match the described defaults.

Ofir,

Thank you for the information, but as you could read, this is what I did already.

I will provide the serial numbers, but why? In your description of how to do it, you describe changing the port number. If I must change the port number, then they are not at default, so it appears as if you know this and in which case there is nothing to investigate.

Can you describe what your expectation of 'default' is then? I think you know what mine is... I may have missed it, but if the documentation says 'You must download by serial port first' then that is an acceptable answer and I will crawl back into my hole and I apologize in advance if I missed that part. Please describe the manual that this is in, and the page number so I may review and chant my Mea Culpas.

V350-35-T2

KM0300162 / 171

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Hi Bill,

First of all - you're right - it's possible to connect direct via Ethernet - the way Ofir already posted. Small tip - you can see default PLC Name in info mode too.

In general, the controllers need to come with default Socket setings. I want ot understand why in your case they was not. That's why I need the serial numbers. In addition:

Were the controllers entierly new - from the box when you started the operation?

Did you personally installed the Ethernet cards?

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I did install the ethernet cards myself, and I was the first one to power them up, once I got them. This has happened to me before so I include a ladder net that sets all 4 sockets to default in all my Unitronics programs so that I don't have to assume anything - you know what 'assume' means, right? I had an Army Sergeant Major (I was in the Navy, mind you) tell me about 'ASS-u-ME' one day long ago early in my military career - it was not a pleasant discussion.

What is in SDW9? I get the PLC name from Info mode -> Version -> Software and it is the last item listed. Are they the same value? I get text on the software screen, but obviosuly a number in SDW9. What is the encoding, assuming (I know, dangerous!) they represent the same thing?

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Hi Bill,

We are checking the serial numbers.

Usually, when you start a project, especially with Erthernet card, along with Card setup you set PLC name too. With this, and only with this PLC Name you can then connect from VisiLogic and Remote Operator.

SDW9 holds PLC Unique number. This number is burnt in PLC memory and cannot be changed in any way out of Unitronics factory.

In a new controller, just from the box, the default PLC Name is the Unique number (SDW9 value.

If in your case PLC Name was different from the value of SDW9, this means that someone already downloaded program in this controller. This is what I'm trying to investigate. That's why I need the serial numbers!

What was the "default" PLC Name you found in Info mode of this new controller? Maybe this can give me some direction?

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I don't know, as I already have my programs with my programmed PLC-name on them. However, looking at SDW9 on another system I have, that looks very similar to the format used for the PLC names I used yesterday morning that worked with Visilogic. So I would say the PLCs had the default name, your serial number. Therefore I conclude PLC name was set to default, as you intended.

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Not to kibitz, but none of the V570 units we've shipped have ever come with usable default port numbers set (and that's quite a few units). Also, there's a button in info mode to set default IP addresses, which _doesn't_ set up any default ports.

Since setting up ethernet comms on the V570 is more than a one-step operation, I've given all my service techs an SD card which has a clone file for a simple application which sets up the ethernet port and establishes a default generic PLC name. That way, when my techs need to set up a new V570, they just pop in the SD card, clone the PLC from the card, and they're ready to hook up VisiLogic (that way I'm also sure of what OS version the V570 is running.)

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Just to throw this out here -

Pop off the back cover and make SURE the ethernet card is seated completely flush. It's possible to put these in and not quite have them in all the way.

I've done it, a guy I helped out did it, lots of people have done it...

TM

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Just to throw this out here -

Pop off the back cover and make SURE the ethernet card is seated completely flush. It's possible to put these in and not quite have them in all the way.

I've done it, a guy I helped out did it, lots of people have done it...

TM

This has not happened to me so much, but what I do is end up bending the pins on the bottom of the top board when trying to reassemble the system. I noticed the bottom board (from the viewpoint of the bottom, so when the LCD is face down during assembly) has cool little connectors that seem to snap together easily onto the LCD screen. But when I put on that last board, with the jumpers for IO, I bend those pins. Then I have to get out needle nose pliers and try to straighten. Ugly. I was just telling my coworker while working on these two units I wish I could buy them pre-configured - idea - I'll talk to my distributor to see if that is something he will do for us. I provide the spec, he can install the hardware parts in the case and set the jumpers. I wouldn't even have to open the back case!

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Joe,

Unless my units are defective, your not technically correct. If you read my post, you can see that adjusting (all in info mode):

1. Transport protocol

2. Port number

2. IP

3. Looking up default PLC name

then connection can be made. As described, I was then able to to download. My issue was not to gain connection - it is why out-of-the-box we can't, when it is only a settings issue that does not match the described defaults.

I hate not being technically correct. Presented with this challenge, I pulled a V350 out of stock and followed Ofir's instructions. I was able to connect to the PLC using the system ID value as the PLC name. So the "Uni Guru", as my user ID has been labeled, learned something new today. I was wrong, and I'll be more technically correct in the future.

As far as being able to connect out-of-the-box, you have a valid point. I have a feeling that the reason the Ethernet defaults are what they are is for security. It forces you to touch the PLC to initially get to it and configure it for your system. Only the programmer knows the name, and it's different for each unit. Other PLC manufacturers use BOOTP as default to force the user to configure the port with their software.

I've been selling Unitronics for 10 years now, and I've programmed most of the others in my professional career. My experience has been that the majority of PLC users are not good with communication and they see it as something that is great in that it reduces wiring but scary because they're not familiar with how to set up all the handshaking and data transfer.

Imagine this scenario - a user puts an Ethernet card in his PLC because he wants to get to it over his network. With no other programming, an O/S designed for easy connection sets the card to 192.168.1.1 and the name to "Unitronics". If the user is not a network guy, the odds are high he's going to leave it at those parameters or just change the IP address; he can do that from the front panel. He probably won't change the name, as this requires reading the Help on networking or looking at example applications. This all takes too much time. He bought the PLC to control a machine, and he's much more interested in writing ladder logic to do that.

What you've got now is a PLC on a plant network that's pretty easily hacked. Our software is free and downloadable to anyone who wants it. Once the IP is determined (easy with a scanner), and if we have a default name, any clown boy connected to the network and so inclined could completely write over the existing program.

How many times have you powered up the wireless your laptop and discovered a network called "linksys" that let you on with full access?

So I guess my point is that Ethernet is not supposed to be super-easy.

The opinion expressed here is mine only and does not necessarily reflect that of Unitronics. I'm sure others will chime in with their own.

Joe T.

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The PLC Name being different on each new unit should be more than enough security to protect the unwary - I'd vote for each PLC to come out of the box at the default IP address and with all four sets of ports set to something known and useful, and that pushing the "Set Default IP Address" button should set the ports to the default as well (or should give a dialog box which offers that option.)

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