How it used to be

Image result for AB PLC 5 processor
DF1 and DH485 Communications Options

In the “good old days” machine builders and OEMs would put PLCs on their machines that did the job of controlling these machines and that’s all they did.  The operators would control these machines locally through push buttons or HMIs and they operated for the most part in isolation.    This type of control has been going on since the advent of PLCs in, let’s say, the 1970s.   Communication through at least the 1990’s was mostly via serial ports on the machines.  Communication to the PLC was via serial ports that would talk Modbus or maybe DF1 or DH485 protocol in the US depending on the manufacturer of the PLC. Those old serial protocols traveled over media that could handle only one protocol at a time.  That Allen Bradley blue hose networks for DH+ only worked with AB PLCs,  Modbus+ cabling networks only worked for Modicon.

 

 

A Data Driven Environment- and a Challenge for the Machine Builder

In the last few years manufacturers who use these machines on their plant floors want more.  They want data, or they want more integrated control or even remote control.  The data may have to do with downtime analysis, Overall Equipment Effectiveness (OEE), quality or safety.  Think about Factory 4.0 or IIoT.  So, of course, now end users of machines need to communicate with these machines through their networks. The advent of Ethernet communications has made this communication possible.     But through the TCP/IP standards every vendor’s equipment can talk over the same Ethernet network.  And the PLCs can talk over an existing network that also has PC data, camera data and a host of other traffic.  Mind you, I’m not saying that’s a good idea but I am saying it can be done.

The Solution for Machine Builders

Things were pretty good until the customers, the end users of these machines, also wanted to talk to your machines.  They are no longer isolated cells, they are part of the plant network.  So now what do you do?  One solution is you  change the address of every device on every machine you send out the door to meet your end user network requirements.  That means that every system has to be well documented and you had better get it right or you may be blocked out of your own devices.

The better solution is to do what you have done at your home and office since the internet stopped being dial up.  You need to use a router, but one designed just for your needs.  At the most basic level routers bridge different networks.  They do it in a couple of different ways which we won’t get into here.  But the simple explanation is routers allow you to ship your product with one set of IP addresses and allow your end user customer to connect to it on their network.  You don’t have to change your addresses every time you ship a machine.  Routers also allow for machine level security firewalls, better diagnostics, event logs, and much more.   Here is a diagram of the solution:

Contact us for assistance.

Please get in touch with Jack Baldwin or Reid Garst at the Braas Company for a detailed solution.   You can reach us at first.last @ braasco.com.