I am trying to implement a data acquisition system for a box factory. The primary purpose of this system is to monitor up/down time, and throughput. I am using Micrologix 1000 PLCs with 1761-NET-ENI for ethernet connection. The working idea is to have a central computer query each PLC. At each station, we plan to have a local computer with a Visual C++ application working in conjunction with RSLinx. This application will allow the user to view the acquired data and enable them to enter reasons for down-time. Thus, we need to have communication from PLC to local station computer, PLC to central computer, and local computer to central computer; all via the 1761-NET-ENI. From the central computer, the acquired data will be dumped to a database. Since I am new to PLCs, this is quite a daunting task. Can anyone offer any advice on how to do this? Will there be any problems with ethernet traffic? Can a Visual C++ application be linked with the RSLinx software? I'm open to any suggestions. Thanx.
Ethernet Communications
- Thread starter eyespyral
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The NET-ENI works great for put a processor serial port on Ethernet. I have only used it with Allen-Bradley processors. The are some limitations with how much the NET-ENI will communicate with. These limitations are called connections.
Go to the AB Knowledgebase at
http://domino.automation.rockwell.com/applications/kb/RAKB.nsf/$$Search/?OpenForm
Type “NET-ENI” in to Keyword field and search the page for (Ctrl+F) “connections”
You may also need to scale up your version of RSLinx to work with your C++ program. I had to do that to get Linx to communicate with Excel.
Go to the AB Knowledgebase at
http://domino.automation.rockwell.com/applications/kb/RAKB.nsf/$$Search/?OpenForm
Type “NET-ENI” in to Keyword field and search the page for (Ctrl+F) “connections”
You may also need to scale up your version of RSLinx to work with your C++ program. I had to do that to get Linx to communicate with Excel.
(8{)} ( .)
Lifetime Supporting Member
I'm a big fan of the "why-build-it-if-you-can-buy-it" school.
I would look into using a small SCADA package to do the operator interface and at least some of the up/down time accumulation. Products like CiTect and Cimplicity can do the accumulation for you. Calculating the actual up-time is often done in PLC code because it's more imune from than the monitoring application.
Regarding communications with RS-Linx if I understand correctly you are planning on having an RS-Linx package at each station. This is a costly approach. Regardless, you should interface with RS-Linx using OPC. RS-Linx is an OPC server and your application would be a client to that server. You can run 1 RS-Linx on a network and have all of your operator stations gather data through that RS-Linx. If you take this approach you'd have RS-Linx on your server and you wouldn't need a polling application (unless you are also saving historical data). The local stations would request data from RS-Linx and display the necessary information.
If you went with a small SCADA package (above) you could probably use the built in DF1 (Allen-Bradley RS-232) driver that comes with most packages, connecting each station to it's own PLC. You wouldn't need to connect the PLC's together either.
Regardless, there are lots of ways to do this. Things like system location (ie. distance between system components), expandability (is this thing gonna grow?) etc. will all influence the final architecture. The task is not so daunting as it was a few years back.
Good Luck,
(8{)} ( .)
I would look into using a small SCADA package to do the operator interface and at least some of the up/down time accumulation. Products like CiTect and Cimplicity can do the accumulation for you. Calculating the actual up-time is often done in PLC code because it's more imune from than the monitoring application.
Regarding communications with RS-Linx if I understand correctly you are planning on having an RS-Linx package at each station. This is a costly approach. Regardless, you should interface with RS-Linx using OPC. RS-Linx is an OPC server and your application would be a client to that server. You can run 1 RS-Linx on a network and have all of your operator stations gather data through that RS-Linx. If you take this approach you'd have RS-Linx on your server and you wouldn't need a polling application (unless you are also saving historical data). The local stations would request data from RS-Linx and display the necessary information.
If you went with a small SCADA package (above) you could probably use the built in DF1 (Allen-Bradley RS-232) driver that comes with most packages, connecting each station to it's own PLC. You wouldn't need to connect the PLC's together either.
Regardless, there are lots of ways to do this. Things like system location (ie. distance between system components), expandability (is this thing gonna grow?) etc. will all influence the final architecture. The task is not so daunting as it was a few years back.
Good Luck,
(8{)} ( .)
rsview
We are using rsview32 to get up and downtime for all of machine of our factory ( Electrolux Montréal )
With rsview32, we get this data by a opc and we show this information on the intranet with rsview webserver.
Everybody can take a look on his laptop of all up/downtime anywhere, anytime.
We are using rsview32 to get up and downtime for all of machine of our factory ( Electrolux Montréal )
With rsview32, we get this data by a opc and we show this information on the intranet with rsview webserver.
Everybody can take a look on his laptop of all up/downtime anywhere, anytime.
AB TCP ethernet communications
If you want to communicate with AB PLCs over ethernet and can write an application in C++, VB, or Delphi then try the Automated Solutions ASABTCP active X control. I am using it to communicate with NET-ENI, SL5/05 and PLC5/20E. No problem. You don't need RSlinx and the runtime licence is free, you only pay for the development version.
http://www.automatedsolutions.com/
You shouldn't have any trouble with ethernet traffic but the NET-ENI only handles 6 connections at once and the serial comms side limits the data transfer speed.
On the plus side you can get the NET-ENI to e-mail the plant manager when the operator makes a mistake!
If you want to communicate with AB PLCs over ethernet and can write an application in C++, VB, or Delphi then try the Automated Solutions ASABTCP active X control. I am using it to communicate with NET-ENI, SL5/05 and PLC5/20E. No problem. You don't need RSlinx and the runtime licence is free, you only pay for the development version.
http://www.automatedsolutions.com/
You shouldn't have any trouble with ethernet traffic but the NET-ENI only handles 6 connections at once and the serial comms side limits the data transfer speed.
On the plus side you can get the NET-ENI to e-mail the plant manager when the operator makes a mistake!
If i were you I would use Rslinx Gateway on the central computer
i wouldn't use the NET ENI but instead something similar but cheaper more versatile called digi one serial port to ethernet converter
http://www.digi.com
from rslinx gateway configure the driver for each plc
then from the remote computer you can use network dde to exchange data with the plc you want
i wouldn't use the NET ENI but instead something similar but cheaper more versatile called digi one serial port to ethernet converter
http://www.digi.com
from rslinx gateway configure the driver for each plc
then from the remote computer you can use network dde to exchange data with the plc you want
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