What would you say is one of the most important pieces of equipment in an automobile assembly line plant--something that is tied to nearly every function in the production of a new car? 

Give up? It’s easy: the air compressors. When a worker puts on a tire or attaches the new seats, they use a pneumatic tool. These tools are run by...you guessed it...air pressure. So, it goes without saying that the air compressors in an auto assembly line plant would be of primary importance. 
 

Central Control for the Compressors 

There are a total of 8 Atlas Copco compressors in the Shanghai plant of a major automotive manufacturer. Six of these compressors are the ZH model, which is a centrifugal type, having an Allen-Bradley® SLC™ 5/03 embedded in their control systems. The remaining two compressors are the Z-pack model, equipped with built-in Modbus® communications. This created a problem in networking the compressors together, since the Allen-Bradley SLCs are not Modbus-compatible. The system integrator, Shanghai Yuandong Science & Technology, contacted Rockwell Automation and ProSoft Technology. They installed ProSoft’s Modbus communication solution into the SLCs onboard the ZH compressors, which then allowed all of the compressors to link to the HMI Host Station via the DH485 network.
 

“Normally every Atlas Copco compressor would be controlled individually,” said Chen Zong Liang, General Manager of Shanghai Yuandong. “With individual control, we found that some compressors would load, unload, and even stop running simultaneously. This made compressor output very inconsistent and therefore unstable. By using ProSoft’s module, we were able to directly connect Allen-Bradley’s SLC with Atlas Copco’s compressors using the Modbus protocol. With central control, it was possible to stagger the actions (start, load, unload or stop) of every compressor according to the charge situation.”
 

“Enabling the compressors with central control was easy to implement and created a smooth-running operation,” said the ProSoft Regional Sales Manager who worked on the application. “Not only did it help increase production, it created a cost savings in terms of electricity and maintenance costs. All of this translates into higher profits.”
 

When asked how the ProSoft module improved the plant processes, i.e. functionality, speed, convenience, or financial benefits, Liang simply replied, “It just can’t work without it!”
 

Modbus Interface
 
 

“With these Modbus communication interfaces, manufacturers are making a great deal of data available to the processor that can enhance the system control,” said ProSoft founder Doug Sharratt at the time of the application. “The Modbus module, when configured as a Master, is able to read and write to these devices, allowing the SLC ladder program direct access to the device’s data.”
 

In the past, many communication systems were closed. Since the Modbus protocol is open it has become an industry standard for many industrial devices available today. 
 

Learn more about ProSoft Technology’s Modbus solutions here.

A while back, a major oil company took a good look at their legacy system and didn’t like what it saw.

The centralized control system, which had been installed in 1978, used multi-drop, leased telephone lines. Four operators at consoles in Houston, Texas, controlled the pipelines for 12 hours a day. This left large stretches of its pipeline unmanned, with no support. The system was already operating at maximum capacity and had many technical risks. They were concerned about the availability of replacement parts for the old RTUs, loop controllers, and alarm annunciators. They needed to know the exact contents of a pipeline, wherever it was, instead of the meter-in/meter-out leak detection they had. Their data entry system was cumbersome, in some cases requiring that data be entered two or three times.

“We reviewed our control system strategy and concluded that we had a unique and hard-to-maintain system. It consisted of dedicated, custom-built and programmed RTUs, along with a lot of odds and ends,” said the company’s lead project engineer.

In short, the company needed to improve its pipeline reporting system by adopting a platform that would let it automate the manual activities to improve efficiency in its small-diameter, high-pressure pipelines running throughout the United States.

First, the company abandoned its old leased telephone lines and went to a VSAT satellite system. The VSAT Ku Band Network system supports 170 sites where the company has 200 PLCs and RTU addresses handling about 20,000 I/O points.

In addition to the VSAT, the company installed a dial backup using analog lines and communicating via the Modbus® protocol to 140 critical sites.

 “When the company installed the new equipment, the old equipment couldn’t communicate with it,” said Ken Hopwood, Software Engineering Manager at ProSoft Technology. “So, they used a ProSoft Modbus module as an interface.”

“When the company approached us, they needed to eliminate the need for continuous polling that was necessary on their old system,” Mr. Hopwood said. “It created communication delays when using the satellite which were expensive. The module we created for them is basically a Modbus Slave but with a few modifications. One, it has Report by Exception, giving it the ability to send timed, unsolicited data reports to the Master Station in Houston. This eliminated the need for continuous polling. The CMS module also contains some specialized data that is unique to the company.”

“In the past, many communication systems were closed,” said the ProSoft Regional Sales Manager who helped the company. “Since the Modbus protocol is open, it has become a de facto industry standard for many industrial devices today, especially in the oil and gas industry. The popularity of our Modbus module doesn’t really surprise me. I see instances like this company’s on a weekly basis. Using the Modbus module to communicate from old equipment to new equipment is simply the most cost-effective way (and in some cases, the only way) to accomplish their goals.”

Learn more about ProSoft Technology’s solutions for the Oil and Gas industry here.

Californians have always been faced with the problem of how best to conserve, control and move water. California has a wide diversity of climactic and geographical contrasts. The northern part of the state, with its alpine forests receives as much as 100 inches or more of rain per year, while the central and southern parts of the state range from arid desert to fertile farm land with some areas receiving less than 2 inches per year. Population centers have grown up in locations where there is not a sufficient water supply. The central valley, running from Sacramento to Bakersfield, contains some of the most fertile farm land in the world, most of which is dependent on irrigation. Because of this need to conserve, control and move water to areas of need, California developed the State Water Project, the largest state-built water development project in the United States

One water district is a small part of this statewide water project. Located in the southern portion of California’s fertile San Joaquin Valley, the district supplies irrigation water for over 45,000 acres of crops including grapes, citrus, almonds, and pistachios.

A while back, the district decided that the level of reliability was not acceptable in its current system. Parts were no longer available for their legacy system and buried wire was degrading with age. So, the district decided to upgrade its system to allow remote control of facilities and monitoring of power usage and quality, and to enhance the ability to perform load shifting for remote facilities.

“The water district needed a name-brand solution with local support,” said the operations manager for Prousys, Inc., the system integrator chosen to construct the new system. “We recommended Allen-Bradley® hardware.”
 

Allen-Bradley processors were installed to replace the aging Westinghouse PLCs at each of the five remote well sites. In order to monitor power usage and detect anomalies in the Multilin PQM Power Monitors, a ProSoft Technology Modbus Communication Module was installed in each processor.

“This is a perfect example of how ProSoft modules are used ever day to connect Allen-Bradley hardware with other networks,” said the ProSoft Regional Sales Manager who worked with the district. “We receive numerous requests on a daily basis for modules in the water/wastewater industry. Because our modules are designed to be used as ‘in-rack’ solutions for Allen-Bradley processors, it is a cost-effective way for plant managers to use their existing Allen-Bradley equipment with other network’s protocols.”
 

A SCADA Master Control system was also installed consisting of an Intellution Fix/DMACS HMI and an Allen-Bradley PLC with two ProSoft DF1 Communication Modules in order to poll five well sites, three pump stations, four reservoirs, and five check stations via a Data-Linc radio and modem.
 

Redundancy is a key factor in most water systems. Prousys installed and configured a second Intellution HMI to provide control redundancy. In the event of a failure in the primary controller, the system switches to the backup, ensuring seamless control in the plant.

“The system will keep right on running if the HMI goes down,” explained Prousys’ operations manager.

 The system’s pump stations are controlled according to the levels in the associated wells. The precise operation of the system depends on the accurate measurement of system levels and flows across the entire water system. Flow and level meters relay these measures back to the central control room for monitoring and control. Allen-Bradley PanelView™ terminals were installed at each of the three pump stations.
 

“The new system now gives the water district full control of all remote sites,” said Prousys’ operations manager. “The SCADA system can now track station flow rates, overflow events, well level, in-flow, and out-flow. They also have the capability to detect numerous system failures including power, high/low voltage, phase imbalance, high/low amperes, frequency, load factor, and low water level. Since the ProSoft modules communicate over the backplane with the Allen-Bradley processors, they were critical to the success of this project. ProSoft provided the ‘missing link’ in the communication chain, seamlessly allowing connectivity between these differing networks.”
  
 Learn more about ProSoft Technology’s solutions for Rockwell Automation® platforms here.

Picturesque gardens dot the city of Suzhou, in eastern China’s Jiangsu province.  Some of these gardens, known as the Classical Gardens of Suzhou, date back as far as the 11th century, and were designed by some of China’s renowned scholars.  Nearby, numerous canals crisscross the city that is known as the Venice of the East. 42 percent of the city is covered in water through its canals and waterways.

“Suzhou City is one of the most famous tourism cities in China,” said Gary Zhang Zhen Hua, ProSoft Technology China Sales & Technical Manager.

But while the area is likely one of the more picturesque in the world, thanks to its gardens and canals, it is also highly populated with more than 10 million people and is largely industrial. Like many cities in China, automobile congestion is a problem. The city needed to install its first subway system to help alleviate its traffic congestion.

After more than four years of construction, the Suzhou Metro Line I opened a while back. It encompasses 24 stations that connect the east side of the city to the west side over about 16 miles. The line extends from the Mudu station in the eastern portion of the city to Zhongnan Jie station in the west, near Suzhou Industrial Park. Metro Line I is the start of a larger subway system in Suzhou. (The city has now also constructed Metro Line II, which travels north and south.)

“The Metro Line I is the first Metro Line in Suzhou, which goes from west to east, connecting two economic development zones and the downtown,” Gary Zhang Zhen Hua said.

More than 150 ProSoft Technology Modbus® ‘C’ Programmable communication modules were installed in the Metro Line’s Building Automation System, which plays a vital role in the underground tunnels and stations that make up the subway. The modules allow Rockwell Automation® ControlLogix® and FLEX™ I/O systems to communicate with and gather data from ventilation systems and air conditioners, as well as monitor the overall environment inside the subway system.

Most people think of a train speeding down an underground tunnel when they think of a subway. A Building Automation System is likely the last thing that comes to mind, but without this critical piece, a subway would not be able to operate.

“The ProSoft Technology solution is a good one,” said Jianshui Gan, the Building Automation System engineer working on the Suzhou Metro Line I. “We chose ProSoft Technology’s product because they are the communication adapter between field devices and the ControlLogix controller.”

Hundreds of thousands of people per day, tourists and Suzhou residents alike, now use the Metro Line to get from one end of the city to the other and avoid automobile congestion.  The train rolls on – in part thanks to ProSoft Technology’s Modbus modules.

Learn more about ProSoft Technology’s in-rack ‘C’ programmable modules for Rockwell Automation controllers here.