PLC AND REMOTE I/O REPLACEMENT PROJECT ON A 6 COLOR FLEXO PRINTING PRESS

LPR AUTOMATION

December 2017

In June of 2017 LPR was contacted by CED, the local Allen Bradley distributor, about a customer who was having a problem with communication issues shutting down a printing press while running production. This issue was causing downtime, increased scrap/waste and the inability to meet production demands due to unplanned downtime.

We planned to meet with the customer to review their issues and survey the system. After meeting with the customer, we found the following situation:

The printing press was a six color flexo machine originally installed in 1993. The control system was an Allen Bradley PLC 5/15 connected to six SLC500s (one in each

printing unit) that were communicating via Remote I/O through the use of 1747-DCM modules. The SLC500s were acting strictly as remote I/O adapters with no logic control in them.

The interface to the drives and support hardware was done through contact closure inputs and isolated contact output modules.

There was no HMI to provide any type of operator interface control or alarming. The PLC 5/15 was experiencing faults on the Remote I/O channel that was randomly

stopping the press. The customer had previously checked all the Remote I/O “blue hose” and was confident

that the problem was not in the communication cabling. This left the PLC itself or any one of the 6 SLC500 1747-DCM communication modules as suspects.

The customer did not have the existing program file for the SLC5/15 or any of the SLC500s. Nor did they can get online with any of the processors to extract the files for backup. This lack of program backup had the customer in a high-risk situation if a processor failure occurred.

LPR decided that the first step to help this customer was to get program file backups in place. That way the customer was protected from a more significant failure in the future, regardless of what else was done to solve the intermittent communication failure. After the backups were secured, we would work on determining what options were available to eliminate the main problem.

LPR had to secure the required interface hardware and file extraction utility for the SLC500s in order to upload the programs as that vintage SLC500 used a 3rd party software supplier. We were able to complete the file uploads from the PLC5/15 and each of the SLC500s onsite and deliver the backups to the customer in one day.

Once the backup programs were secured, we focused on reviewing the logic in the 5/15 and SLC500s to determine what would be involved in program conversion. We also worked on checking pricing and availability of replacement PLC5 and 1747-DCM modules, as they were the most likely contributors to the communication issue. After determining that it would be cost prohibitive and difficult to obtain replacements, we felt like there was no value in trying to replace modules in the system to try to correct the problem. Further discussions with the customer indicated that they wanted to continue running the press as there was no money in their budget to replace it. Based on that we proposed the following to the customer:

Supply and replace the PLC 5/15 with a CompactLogix PLC. Supply and replace the SLC500s with Ethernet I/P based 1734 Point I/O modules in each

printing unit. Supply a PanelView Plus mounted in the main enclosure to provide additional operator

interface features as well as messaging and alarming. Supply a Stratix 2000 switch for the Ethernet I/P connections. Update the existing drawings with revised and new .DWG files. New inputs defined to

pick up existing hard-wired fault circuits. Convert the existing PLC 5/15 program to RSLogix 5000 to run on the CompactLogix PLC Create required operator interface screens and alarm screens for the Panelview using

FTView. Complete system mock up and testing at the LPR facility. Coordinate installation, startup and commissioning with customer’s electrical

contractor.

The customer had also contacted the OEM printing press supplier for a proposal on an upgraded system, but that proposal was deemed too expensive. Additionally, there was a limited window of opportunity to make the conversion as the customer’s seasonal demand for product was approaching.

LPR was awarded the PO for this project and was able to order and receive all the hardware, complete the drawings and create the PLC and PanelView programs within 2 months. Installation timing was coordinated with the customer and the electrical contractor to meet the

customer’s production schedule. Installation was completed in 1 ½ days and the machine was running by the end of the 2nd day. The electrical contractor did an excellent job and was complimentary of LPR’s preparation and execution on the job. This work was completed prior to the customer’s busy season and allowed them to meet their production requirements due to reliable operation of the printing press.

Subsequent follow-up with the customer indicated that the press was running very reliably and that production demands were being met.

Main control panel with PLC 5/15 prior to upgrade

One of the six SLC500s with the 1747-DCM module prior to replacement with 1734 Point I/O

System mock up running at LPR facility prior to installation. Ethernet I/P

addresses set and all devices communicating

Main control panel with CompactLogix processor and Stratix switch mounted.

Wiring is not complete.