Bill Smith

See this post: this has the steps I needed to make this download to a brand-new work.

The Rockwell samplecode website has code for Modbus. I have looked at it in the past, but never used it. I dug it up again and see that it is serial only, so no ModbusTCP support. My number 5 is in error, so it becomes: 5. Convince AB to support ModbusTCP. Good luck! The Logix5000 series support it in code.

AB Micrologix devices use Ethernet/IP (explicit with PCCC encapsulation) on the Ethernet port. Unitronics does not support this, instead, they support ModbusTCP. Which Micrologix? The 1100 will only do explicit Ethernet/IP messaging, but the 1400 will do a raw protocol as well. I suppose you could write your own protocol between the two devices, but that would be a fair amount of work using the 'raw port' (my words) capability of each device. Suggestions: 1. Buy protocol converter. There are many and they cost a few hundred dollars (and up). 2. Use serial - I think Unitronics supports DF1 on serial, so that should work (never used it). 3. AB supports Modbus on serial, so use serial with Modbus. 4. Convince Unitronics to support Ethernet/IP (I would like this, too). 5. Convince AB to support ModbusTCP. Good luck! The Logix5000 series support it in code. 6. Write your own protocol and use it over TCP/IP using the raw ports capability of a 1400 and Unitronics devices 7. I am sure I missed some...

Wouldn't you have to ask the printer manufacturer?

The V350 has 64, so it must be product specific. You could do some float math as an integer with implied decimals. Since there is not a good float display primitive for the HMI, I find the implied decimal approach to be frequently useful. Also with the formula block, you may find you need fewer floats to store intermediate calculations.

This pump control configuration seems odd. Do you have a manufacturer / part numbers for this pump control hardware?

I really can't figure out what the issue is but anyway i'll give it a shot - Modbus has a Unit Identifier, so not sure why you can't have all the pumps on one Modbus RS485 link. Just address the devices you want to, don't address the devices you don't want. Except for broadcast, messages destined for another device are to be ignored. The ethernet port supports multiple connections - 4 ports if I recall. It's very unusual to hook a modem (these are usually serial) to an ethernet port so not sure what your doing, but whatever it is I would assume you still have three other ethernet ports available. With these other ethernet ports available (not physical ports - TCP or UDP ports) you can put in a an ethernet/serial converter. There are many of these on the market - search google for 'serial to ethernet'. I like Digi (One IAP) or Schneider Electric (ETG100), but have used many of these from B&B Electronics too. Your ModbusTCP request will go to this device, be converted to serial, sent to your serial device, and the response will get returned in the reverse manner transparently.

The Modbus spec (www.modbus.org) requires that register addressing be from 0-65535, and the Modbus application layer protocol only allows two bytes for the address for a max addressable register of 0xFFF or 65535 in protocol. So if Unitronics demands higher values than this, then it really isn't Modbus because it would clearly break the specification. I checked slave addressing in the help file and see the MLs are available starting at index 0x7000, which is 28762 (decimal). Therefore, Unitronics appears to be complaint to the addressing requirements of Modbus. So what are you entering in the G3series exactly, and for which registers? I use Redlion and Unitronics products all the time and never have any trouble with Modbus, with either device acting as Master or Slave (over Ethernet).

Suggestions - 1. turn of auto negotiation on the switch and force to 100MB full duplex. 2. make sure you NOT using a crossover cable - it should work either way, but remove it as a potential error source I would force the Unitronics to the same settings if I could, but I couldn't figure out how to do it. Conversely, if you find the ports are manually set already, try setting them to auto negotiation.

A double word is 32 bits, so represents a much larger integer than you have listed. Where did you get 25 bits from? For a reference of datatypes, try http://en.wikipedia.org/wiki/Integer_(computer_science) Check the helpfile for the Bit -> Num function. After reading it, I can say the Unitronics team did a good job representing how this function works, particularly in your case.

Thanks for this reference. This is good. I have a project that I was considering rolling out the advanced webserver on... it's now obvious that this would take a lot more work than I anticipated to add the feature to a working program. I need to think about it.

Are you sure the port is correct? You can check here for a similar issue. On the V350, I can verify all parts: IP address, port, and system name, of which we need all three for success. Can you get a Wireshark packet capture of the problem? That will likely nail the cause - 1. If we see TCP SYN packets, but no one responds, the IP address is wrong or the target system is not connected to the network. Ping success means you made it past this hurdle. 2. If we see TCP SYN packets and they are responded to with a TCP RST, then the port is not configured properly (issue in above mentioned thread) - port number and protocol type (TCP). 3. If we see the TCP connection establishment, we can look in there and see what the problem is. It is likely a system name issue at this point.

Unitronics, It's been two weeks, do you have any resolution on the default Ethernet ports issue presented?

I agree with Damian - the time horizon I envision is more like 'forever' for saving the old forum stuff. Certainly into the double digit years. If you still have product that is referenced in those forums in the field, please keep the old forum (keep links to old software and manuals, too!).

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!