Many process controls look like they’ve been touching their toes and going out for a jog. That's because their software, support components and networking are increasingly unhitching from traditional, rigid, hardware-based and hardwired formats to become simpler, more flexible, easier-to-implement solutions that give users new freedom to run and optimize applications.
This trend is illustrated by isotropic graphite manufacturer Toyo Tanso USA Inc. in Troutdale, Ore., which offers silicon carbide surface treatments to protect substrates. Its batch automation process is performed in multiple reactor vessels with varying specializations that require careful management. To better automate this process with many I/O points and controls that need to be easily programmed and deployed, Toyo Tanso recently implemented eight Opto 22 Snap process automation controllers (PAC) that are configured to communicate with other controllers, use the PACs' distributed control and intelligence features, and preserve uptime.
"Ladder logic is useful for basic, on/off procedures and control, but it can be difficult to troubleshoot. Snap PAC's scratch pad features and PAC Project tools can step in and out of a control block to pinpoint exactly what’s happening, which makes troubleshooting easier."
I/O modules and Snap PACs in Toyo Tanso's batch surface treating application control pumps and motors, temperatures, and power and pressure to the vessels; heat to the vessels; and the cooling water supply during the coating process. Pressure and temperature are both controlled using PID loops that run on Snap PACs’ built-in I/O brain. Other vessel dynamics are controlled by Snap PAC, including dozens of valves in each vessel. As a result, Snap PAC and I/O help monitor pH and pressure during coating, while maintaining setpoints using PID loops and other control points. The vessels have more than 1,000 I/O points for control and monitoring during batch runs.
“Our production environment is busy and physically demanding, but it also requires precise control of all its interacting systems,” says Peter Souvanna, IT manager at Toyo Tanso USA. “Ladder logic is useful for basic, on/off procedures and control, but it can be difficult to troubleshoot. Snap PAC's scratch pad features and PAC Project tools make it easy to move data in and out of the controller. They can step in and out of a control block to pinpoint exactly what’s happening, which makes troubleshooting much easier. Plus, their HMI tools offer standard features in the software that let us to build rich HMI screens to know exactly what’s going on with our process at all times.”
In addition, Toyo Tanso USA implemented Opto 22's groov mobile interface tool to develop a gas monitoring system that can be accessed directly by operators’ mobile devices. During the coating process, potentially dangerous gases are used, and groov acts as a backup to the standard control system HMI. “Our groov Box also supports unlimited concurrent connections and user accounts, allowing the entire plant to use one unit for all of our operators,” adds Souvanna, who also took advantage of the redundant Ethernet jacks on the PAC controllers to connect to its production network and business network. “If there’s a broadcast storm or network outage on the business network, the controller isn’t affected and continues to operate.”
Of course, the main benefit of simpler, more flexible controls is they can make migration projects easier to design and implement. Such was the case with a polypropylene unit at Braskem Europe GmbH in Schkopau, Germany, which recently upgraded from a Dow Chemical Co. Manufacturing Operating Discipline (MOD) 5 proprietary distributed control system (DCS) to a Honeywell Process Solutions Experion Process Knowledge System (PKS) R430.
The project in Schkopau began in 2013, and I/O cutover, loop checks and startup occurred in August-September 2015 during downtime scheduled every five years. "This was a complicated and risky migration that required many resources," says Michael Martin, senior process control engineer at Braskem. "We've had no DCS-related plant shutdowns since cutover, and we gained new technologies and capabilities from this migration. Production rates and online time percentages have been greater than or equal to yearly targets."
Overall, the MOD 5 to PKS R430 migration at the Schkopau facility included:
- About 7,000 I/O;
- More than 700 MOD 5 graphics migrated to Experion HMI;
- More than 1 million lines of MOD 5 software code and comments;
- Tracking, documenting and migrating about 100,000 MOD 5 variables;
- Transitioning more than 6,000 MOD 5 modules to about 4,500 Experion control modules;
- Migrating more than 50,000 AspenTech IP21 historian tags;
- Moving nine Siemens GC analyzer data links to Modbus/TCP via peer control data interface (PCDI) blocks; and
- Developing 30 control module templates.
"We also used Honeywell's worldwide cloud development system, which was employed by users in Germany, India, the Czech Republic, the U.S. and elsewhere," explains Martin. "We had to understand MOD 5's state-based control and automation architecture, so we could replace the sequence for each unit with sequence control modules (SCMs) as state drivers. Each sequence was comprised of modules for alarms, digital output (DO) logic, analog output (AO) logic, step logic, special calculations other tasks, and they had to be replaced with control modules."
Martin adds that migration challenges and solutions in Braskem's MOD 5 to Experion upgrade included:
- Identifying and developing similar functions when updating its HMI solutions;
- Translating and normalizing MOD 5 equations;
- Updating the polypropylene application's alarms because MOD 5 had limited alarms, and combined many process and hardware alarms to keep totals down; and
- Replacing MOD 5 interfaces to third-party devices with Honeywell's Peer Control Data Interface (PCDI) and Modbus TCP network.
"MOD 5 operators were required to read Dowtran code to run their plant, and MOD 5 was a closely combined basic process control system and safety instrumented system, which we had to break apart. This also meant migrating from MOD 5 PIDs with output ranges depending on fail open/fail closed to Honeywell PIDs."
"MOD 5 uses logic to enable and disable alarms, so we had to ask, 'How do you program this?' and 'How do you effectively visualize alarm status and trip points?'" says Martin. "MOD 5 instrumentation failure logic also had failures driving process variables to positive full scale and negative full scale, and generating combined process and instrumentation failure alarms. This was replaced with Experion single alarming and custom faceplates. We also converted MOD 5 analog output ranges and code from MOD 5 0-22 mA to 0-110%, and from Honeywell 4-20 mA to 0-100%. We also had to convert MOD 5's analog filter times.
"MOD 5 operators were required to read Dowtran code to run their plant, and MOD 5 was a closely combined basic process control system and safety instrumented system, which we had to break apart. This also meant migrating from MOD 5 PIDs with output ranges depending on fail open/fail closed to Honeywell PIDs, as well as converting PID tuning constants, correctly capturing setpoint ranges, and capturing input failure, interlock and other PID actions."
HMI graphics were removed from MOD 5 that had required a lot of space for shapes and added symbols for alarms and logic, and transitioned to Experion's that needs much less space for shapes, removes unneeded symbols, and uses dynamic alarm symbols. "MOD 5's DO and digital abort logic was replaced with Honeywell's Interlock function block, and reading code was replaced with its Dynamic Logic Faceplate," adds Martin. "Also, MOD 5 dynamic alarm logic was replaced with custom data block and logic, while MOD 5 DM Latch alarms were replaced with template logic, HMI and message block to acknowledge and clear latched alarms."
Migrating from MOD 5 to Experion gave Schkopau's polypropylene plant a variety of new technologies and capabilities:
- Virtual computing solution for L3.0 and L3.5 servers and PCs, including virtual machine replication across redundant host servers, and rapid deployment of new servers and PCs;
- Integrated disaster recovery, including automated Acronis backups for all physical servers and PCs, automated virtual machine replications and backups, and tape backup for offsite storage;
- AspenTech IP21 Data link migrated to OPC, which allowed improved architecture with redundant data collectors and Experion redundant OPC servers, and increased the applications data resolution 10 times;
- GPS radio with times synchronized from the C300 controllers to the IP21 server;
- Field Device Manager (FDM) deployed to interface with over more than 800 DCS and SIS HART devices;
- Metso PlantTriage loop-tuning solution, which minimized plant optimization tasks following plant startup; and
- Safety management by integrating Control Builder software and HMI graphics, as well as implementing universal Rusio I/O modules that work with all I/O types, are HART enabled, and communicate directly to FDM via FTE Ethernet.
Weekend upgrade without downtime
In a similar boat, vanilla flavorings manufacturer Givaudan recently collaborated with system integrator Automated Control Concepts Inc. (ACC), Neptune City, N.J., to replace the DCS and other components at its food flavorings plant in East Hanover, N.J., and accomplish this typically difficult project seamlessly over several weekends during 2014. "The old DCS at the East Hanover facility was having a lot of failures, and the staff was buying parts on eBay, so it was really time to replace it," says Chris Alexander, P.E., Givaudin's process control engineer.
"Gauvidan's staff wanted the new control system to work the same as the old one, maintain existing points, and reuse field wiring and field devices," adds Arlene Weichert, ACC vice president of sales. "However, they also needed the migration to be done with no downtime or loss of production, so we had to do it during a few weekends during the summer."
Alexander reports the plant's new control system and network consists of four primary process areas with 3,800 total I/O points. These areas include large and small distillation applications, flavor concentration and conical extraction, mix and blend tanks, dedicated vanilla extraction equipment, and a roaster/dryer application for vanilla with highly automated sequences. "This is another reason why the DCS migration couldn't cause any shutdowns or lost production because many of Gauvidan's products go to other plants, and so those plants rely on the East Hanover plant," explained Weichert.
To serve these applications, Gauvidan's new control system and network included five ControlLogix L7 controllers, FactoryTalk View SE, Historian SE and VantagePoint Server from Rockwell Automation, while the application's Windows-based server environment also uses VMware components. In addition, several I/O panels were reused by combining existing enclosures with newly fabricated subpanels using Flex I/O modules. The plant's new displays included three thin clients repurposed from existing workstations, an ACP Thin Manager terminal server, another thin client for vanilla processing, and an engineering workstation.
All of these devices are linked via a redundant, multi-mode, fiber-optic network, which includes two main Stratix switches, and a parallel, device-level ring network for motor control centers and solenoid panels. "It was great to gain this redundancy because if any device was unplugged or dropped out, then the rest of the network and other devices could keep running," explains Alexander. "Plus, we can also monitor the network for any breaks."
As for the switch from multicolor to grayscale in the new system's HMI display, adds Alexander, "People asked where the color went, but when we showed them that they didn't need to program in code anymore and could just check boxes, it helped a lot. In addition, the new control system lets us track and trace operating behaviors, and find out reasons for burnt batches or poor-quality raw materials."
Weichert adds the migration was carried out in a series of five short cutovers during available long weekends. "We installed and tested the Ethernet network before cutovers," she says. "Testing each instrument was done long before cutover to create a list of faulty instruments. Repair and replacement of faulty of instruments was done before cutover where possible, and we also did operator and technician training before cutovers. Each one of the five cutovers included about 400-800 I/O points. Operations even left raw material in some equipment and tanks, but we were able to cutover and add the new panels, and then finish the same batch with the new equipment. Finally, all of the required cutovers were finished ahead of schedule."