DSL Systems

The majority of installations in Feed Mills are retrofits where either the mill was not automated before or the old control system had to be replaced. DSL Systems have experience in all types of installations. The simplest installations are retrofits where PLCs have already been installed as then electrical work is kept to a minimum.

For new plants, DSL systems can provide useful advice during the design phase and can help to minimise the installation costs.

The mill was originally built about 15 years ago and the original control system was still in place. This was not suitable for modern milling as it only had a 100 formula store, could not produce any reports and was lacking in any modern energy saving features.

The mill blends 2 tonne batches at 15 batches per hour. Material is then ground and mixed, liquids are added and batches are routed to finished product bins.

Installation was completed in a 3 day weekend. A 3 man team from a local electrical contracting company could do some preparatory wiring work prior to the shutdown but most of the electrical work was done on the first day and finished off on the second day.

DSL's installation team checked each input and output on the PLC, calibrated the weighers and liquids meters, estimated some cleanout times and it was time to try a batch. The third day was spent checking, setting up the cleanout (batch clearance) timers, training and fixing minor problems. Inevitably, there were a few problems but AutoPilot4Feed is quick to correct the configuration so these didn't hold production up for long.

The system has proven to be very reliable and the mill is operated by just one person. It runs faster and records details of every batch for 3 years. AutoPilot4Feed has no known limitations for the future.

Planned future modifications are the integration with the office server and the inclusion of a micro inclusion weigher in the mill; these will be fully automatically controlled of course.

The mill manager is extremely pleased with the system and is happy to tell anyone else so!

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This new mill was built on a green-field site and so was designed to be only automatic from the outset. The mill was designed to be run by only 3 people and so it has just 3 PCs running AutoPilot4Feed under Windows.

The mill consists of a single intake, 2 main weighers feed 2 grinder bins and a vertical dual Buhler grinder. The plant splits into two with 2 press lines fed from one mixing line and the other mixing line feeding a meal conditioning plant.

Three Mitsubishi PLCs are used to control everything in the plant. There are 2 PCs in the control room and one in the weighbridge office. There is a green-screen VT510 display at each of the 2 hand additives points and both of these have a barcode reader to check premixes and drugs and to log batch numbers.

Being so modern, the mill runs with little operator intervention but logs details of every batch, every press run and all operator actions.

One of the PCs in the control room is identical to the Control PC so they have built-in redundancy. A modem allows DSL Systems to provide 24 hour support.

Commissioning a new plant normally takes quite some time but because AutoPilot4Feed is so easy to operate in override, the electrical installation crew were able to perform all their own checks. By the time the DSL Systems commissioning engineer arrived on site, most of the inputs and outputs had already been tested.

The operators all find the system very easy to use and the mill manager is full of praise for AutoPilot4Feed.

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This mill had been built very many years ago and during its life had had many refurbishments. The last refurbishment was in 1992 where unfortunately the wrong choice of control system was made. The control system was very unreliable and since it was effectively purpose built, spares were only available from the single supplier who had left the animal feed market.

The mill is large and complex. It has 3 automatic intakes operated by the truck drivers, feeding 38 raw material bins. 3 weighers weigh batches of 4 tonnes into 2 live bins and from these, 2 grinders feed a 3 tier mixer where liquids are added. There is a standby 3 tier mixer also. A high speed mixer then adds molasses, water and salcurb en route to 8 pre-press bins and many meals bins.

Four press lines include one with an expander, 2 double press lines and one with a single press. Each line has a 2 deck cooler. One line has a crumbler. The presses feed 69 finished product bins arranged over 5 loading bays. A simple slide open warning system prevents drivers from loading their trucks from the wrong bin.

All trucks weigh in and out over a single weighbridge where the weighbridge operator uses a DSL PC to enter truck details.

AutoPilot4Feed consists of 8 PCs; 3 in the control room, one in the QC/Intake office, one for maintenance, one for the maintenance supervisor, one for the weighbridge operator and one for the manager/planner. The Ethernet network is connected to the office network for automatic downloading of formulae and soon for full data integration.

Seven Mitsubishi A1S PLCs are installed where each one replaced the original controller. Fortunately, the original controllers used commonly available plugs and sockets. This enabled extensive testing to be carried out over 2 weekends, prior to the changeover. Each weekend, 3 new PLCs were attached, all the input/output tests performed and the original controller reinstated for the new week's production. This meant that the whole mill could be changed over to the new control system over a long (3 day) weekend with production back to 100% by the Thursday.

Operator training was done on site during the week prior to the changeover and each operator had 2 days training on a simulated system. Everyone is very pleased with the system, its features, reliability and ease of use. As it uses only standard PCs and PLCs, there won't be any problem with spares for a long, long time.

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Johnston and Jeff are a longstanding UK firm based near Hull in Yorkshire. When moving premises in 2002, they decided to build a new weighing and batching plant for birdseed manufacture.

Richard Johnston, the Managing Director, chose DSL Systems after he was unhappy with the company suggested by the main mechanical contractor. He visited Burgess Supafeeds, a petfood manufacturer, which has used DSL for many years. Burgess Supafeeds is a more complex installation but is still easy for the operators to control.

Johnston and Jeff have 2 main weighers with 15 feeders. Extra materials are added by hand and a display close to the hand additives hopper shows what materials to add.

Material is conveyed and elevated to a sieve and into a batch mixer. Liquids are metered in and after mixing, batches are routed to either a one tonne tote filling station or a small bag packer.

The AutoPilot4Feed control system consists of a standard PC running Windows 2000 Pro with a Mitsubishi A1S series PLC providing plant switching and weight readings from the weighers.

The PC shows the whole plant on a single colour graphics mimic and this mimic allows the operator to access all the regularly used facilities. Clicking on a bin brings up the bin allocation program. Clicking on a conveyor or other plant item brings up the manual override facilities. The mimic continually shows the status of the plant, what batches are where and what the weighers are doing. It's very easy for the operator to see at a glance what is happening. Weighing is very accurate and the system has self-learning algorithms to improve accuracy.

Alarms appear in a window and are easy to understand, for example, ‘mixer stopped because of overload'.

The system has extensive management information and logging. Details of all events, alarms, operator actions and batch details are stored for a minimum of 3 years.

The control system was installed and commissioned in 3 days and apart from very minor problems has been fault free and very reliable. The system was installed with a modem and this provides instant support and fault fixes should these be necessary.

Richard Johnston, Managing Director, has been very impressed with the control system:- “ AutoPilot4Feed has been very reliable and is simple for the operators to understand and operate. I'm very pleased with the system”.

Johnston and Jeff are now considering extending the plant to add new bins. There is almost no limit to how much AutoPilot4Feed may be extended so Johnston and Jeff are happy knowing that AutoPilot4Feed will serve their needs whatever they plan to install.

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Sietsema's new feed mill was built by Wagester and Lease in 2003. Designed to be efficient and economical to run, it has the latest AutoPilot4Feed control system from DSL Systems. DSL's partner company in North America is Comco Controls (www.comco-controls.com) and AutoPilot4Feed was installed and commissioned by Comco with commissioning help from DSL's own engineers.

To start, an operational specification was written and this was agreed by the customer, Wagester and Lease and Comco. This was useful to eliminate any misunderstandings early on and to identify any possible problems.

Comco designed and built the PLC panels and these contain an Allen Bradley SLC 505 PLC and remote inputs/outputs. Five PCs running Windows XP are used as workstations for batching, receiving, pellet mill, loadout and one for the manager. All data is held in a Microsoft Access database.

The mill is fully automatic with one truck receiving pit feeding 24 grain and ingredient bins. A hammer mill can grind into 3 ground grain bins.

The main ingredient bins feed a major scale and a minor scale with the salt bin feeding both for better accuracy. There is a separate scale which can be fitted with up to 4 tote bags. Two micro systems each have 12 bins for small additions. A soya flush facility cleans out the micro scales transfer conveyor. Hand adds feed directly into the 5 ton mixer.

Up to 5 metered liquids are controlled into the main mixer and after mixing, batches are transferred to one of 2 pellet bins or 2 bulk mash bins.

The pellet mill is a normal arrangement of feeder, conditioner, Sprout pellet mill, cooler and crumbler. The control system is fully integrated and fully automatic. The operator only has to click on the start button on the graphics and if it is a product which has been made before, click on confirm start. All control of pelleting is fully automatic with all parameters checked 10 times per second to monitor for plugs, temperature, amps etc.

The downstream fat coater is also fully automatic as the fat level is taken from the formula. Pellets are then routed to one of 16 finished feed bins with automatic swap from bin to bin on high level.

Loadout orders are automatically sent from the office commercial computer. Although there is a loadout operator, loadout is controlled as automatically as possible. A moveable 4 ton weigher is moved to one of 3 positions, automatically filled and then moved to the truck hopper for discharge. Filling and discharging the moveable weigher is repeated for larger loads. On completion, AutoPilot4Feed sends the weight information back to the commercial computer which prints out the loading tickets and declaration.

Four of the loadout bins have variable speed dischargers which gives the facility the capability of blending two base products together into the weigher. For this, AutoPilot4Feed has a product type called ‘blended' which is defined as X% of product A and Y% of product B.

As AutoPilot4Feed controls the whole mill, quality is ensured by AutoPilot4Feed's accurate weighing, optimised pellet mill control and by minimising any operator mistakes.

The AutoPilot4Feed control system has built-in redundancy should a PC fail and a modem allows 24 hour support should it be needed. The modem may also be used to install modifications thus minimising the cost of any changes.

Sietsema are very pleased with AutoPilot4Feed and it has proved to be both easy to use and very reliable.

Description: John Thompson and Sons, Belfast

DSL Systems have successfully installed their AutoPilot4Feed control system in John Thompson and Sons, Belfast. The multi-species mill produces approximately 650,000 tonnes per annum from 2 separate batching lines, 4 separate mixing lines and 10 production (press) lines. The production lines have a mixture of single pelleting, double pelleting, BOA conditioners, kettles (cookers) and high retention bio-secure arrangements.

AutoPilot4Feed consists of a high-end Compaq PC running Windows 2000 Server with an SQL Server database. An identical backup PC is always kept up-to-date by using SQL Server replication. A further 32 PCs are used as operator terminals, manager's workstations and for maintenance.

The mill already had 2 Telemechanique Quantum PLCs with Modicon remote inputs and outputs installed and these were re-used together with 6 Allen Bradley SLC505 PLCs and 2 Mitsubishi A1S PLCs. A further 4 Allen Bradley SLC 505 PLCs were added making a total of 5000 inputs, 2000 outputs and 300 analogue signals.

The mill consists of 2 in/out weighbridges, 3 bulk intakes, feeding over 50 bulk raw material bins, 2 separate batching lines, 4 mixing lines and 10 production lines. All 10 lines have fat coaters feeding a total of over 200 finished product bins which then feed onto 7 bulk outloading weighbridges.

AutoPilot4Feed is integrated to other computers on site for the transfer of formulations and production information. A comprehensive reporting system is built-in to provide any report management may require.

John Thompson and Sons chose AutoPilot4Feed because it is designed for feed mills, easy to use and can be integrated to other computer systems. The system also includes comprehensive facilities such as cross contamination checking, long term logging, auditing and maintenance facilities.

Because of the size of the mill, installation was phased in over a number of months. Since installation, the mill Engineering Manager, Aidan Mitchell has been tuning AutoPilot4Feed to make the mill run faster than ever. He says 'AutoPilot4Feed is very flexible and easy to use. When you consider how complex the mill is, it is good to know that AutoPilot4Feed is designed for the job. I cannot think of any other control system so good'.

Because the mill is so efficient, they already have decided to build an 11 th production line and of course it will be no problem for AutoPilot4Feed.

Description: Hydro electric optimising control system

DSL Systems have installed a complete hydro electric switching control system at the Auchnafree Estate in Scotland.

The system maximises the usage of the hydro electric generator whilst ensuring that all demand is satisfied, if necessary from the mains supply. The main advantages of the new system are;-

There are 9 main circuits which may be supplied from either the hydro electric generator or from the mains supply. Mechanically and electrically interlocked contactors are used to switch a circuit between each supply in less than ½ a second. Since the controller itself is on one circuit, an interruptible power supply is used to supply the Wago PLC whilst it switches the circuit which it itself is on. The system measures the current flowing to each circuit as well as the voltage of the hydro electric generator and the mains. The system also features manual overrides and automatic fallback modes. A certified meter is used for ROC calculations.

When water flow is reduced, the hydro electric generator voltage starts to fall. The system then intelligently switches circuits back to mains according to the load on each circuit and the priority of each circuit. The controller knows the characteristics of the hydro electric generator and then switches circuits back to the hydro electric generator when there is sufficient power.

When demand is low, for example, at night, all circuits are normally switched to the hydro electric generator. If there is spare capacity, the system switches in discretionary loads. These are switched on using 13 Amp X10 switching modules which are low cost and require no extra wiring. The discretionary loads are used for heating certain areas and the system has an automatic schedule built in so that these may be sequenced to come on and off at certain times. Text Box:

Although not needed for switching or optimising the hydro electric generator, a Windows XP Pro PC is attached. This shows the current values of all voltages, currents and the status of each circuit and discretionary load. In addition, it can be used to view historical information and graphs of all the main readings. The PC is also used to adjust any operating parameters if required. A modem used in conjunction with PC Anywhere allows DSL Systems remote access should support ever be required. DSL Systems supports all its control systems 24 hours per day, 7 days per week.

The DSL Control System has proven itself in optimising the usage from the hydro electric generator, maximising the return on capital.

Description: John Thompson and Sons, Belfast

Description: Hydro electric optimising control system