Batching, Frequently Asked Questions
The PLC, or Programmable Logic Controller, is an industrial controller that was developed for many different automation tasks, from sequencing traffic lights to controlling huge petrochemical plants. It uses some of the fastest microprocessor chips, identical to those used in many computers, but it has no rotating hard drive to wear out, no Windows operating system and has been designed for a life exceeding 20 years in rough, tough industrial applications. Because it does not use Windows, it is immune to the problems you see in your own computer from time to time. Programs that run in your PC computer are sequential; they complete tasks in a set order, branching along the way when they make decisions. There are thousands of branches in a typical program and if only one of these branches is a dead end, the program stops or “freezes”. Sounds familiar? In comparison, PLC programs run in an endless loop like a wheel turning, repeating hundreds of times every second. Every time around, they check all the inputs, make decisions based on the program in the loop and set all the outputs. It is possible for a programmer to make a mistake in the program, but no mistake will halt the operation of the PLC; it keeps on running. Because it cannot freeze, it performs reliably throughout its long life, requiring little if any maintenance.
In comparison, the average PC computer is built with commercial components that last only a few years; it needs a controlled, cool, dry, clean environment and has little tolerance for the dust and electrical noise caused by the motor starters and valves found in industrial plants. The Windows system can easily be corrupted by unskilled personnel and requires frequent attention; in addition, the frequent Windows updates can shut your plant down at a critical time. BatchTron uses a PLC and is free from all these issues, making it extremely reliable as a result. The data collecting and management tasks, however, can be done on a PC computer in an office environment; if the computer breaks down, the batching system can continue unaided for as long as necessary.
BatchTron’s extreme reliability reduces your maintenance cost by a factor of 10 or more.
Usually yes, occasionally no. When you give us the details for the plant, we set-up the BatchTron for it, making many menu choices. Occasionally we have to add a custom function if it does not exist in the setup menus. The degree of customization depends on the plant; if it is a simple plant like a “dry mix” ready-mix plant, the BatchTron configuration is standard and it can be used on many other similar plants. If it is a more complex precast plant with two or more delivery stations, the answer is inevitably “No, not as it is”. We can always modify the software, however. Since BatchTron has no hard-wired panel controls, the PLC and screen software can be updated on-line to suit any plant configuration. If you do this after the system has been built, however, a reprogramming charge will apply, and the cost will reflect the complexity of the change.
We routinely update customers’ software to accommodate plant changes and additions. For small changes this is done on-line, but large changes occasionally require a plant visit to start up and train operators while making modifications to suit individual preferences. We offer a very personal service and try to accommodate your wishes at all times.
BatchTron is sometimes customized, but can always be changed to suit any plant.
This depends on your present batching method. If you are now using a skilled manual operator, he can probably equal the speed of BatchTron when he is in top form. Manual operators tend to be erratic, however, and they call in sick now and again. BatchTron is consistent, giving you close to the ultimate in speed as well as the accuracy that you require, day after day, week after week. And your skilled operator can get on with other things that need his skill, employing him in a more effective manner.
If you already have basic automation or a PC computer based system, BatchTron can usually increase both speed and accuracy by an impressive factor. Systems older than 10 years rarely have self-tuning and automatic moisture compensation, which means that they must be regularly adjusted to achieve the best performance. PC computers are not “real-time” systems – they run at a speed determined by the background “overhead” processes of Windows which varies all the time. Add to this the updates that shut the system down from time to time and you will see major benefits from BatchTron.
You will be impressed by speed, accuracy and reliability of BatchTron.
Of course, but you need enough electrical knowledge to wire the plant actuators and limit switches to the BatchTron’s terminals according to the electrical schematic. Also, the load cells on the scales must be connected via shielded cables and the scales must be calibrated with test weights. These steps can be done by a local scale company while the wiring can be done by a competent plant electrician. If you have the necessary skills at hand, you probably don’t need our help. Many customers and dealers have self-installed BatchTrons with no problems and saved on the cost of installation. If you find that it is too much, you can always call us to finish the job. Most customers prefer us to be present, however, even if they do most of the work. This is a good safeguard against possible damage or delays and we can train your operators at the same time.
If you have the skills, go ahead. We’ll help if you get stuck.
Most of the manual panel’s functions are duplicated directly from the BatchTron screen and either one can be used with no ill effects. Feed gate and scale discharge controls can be connected in parallel to give manual backups of these functions, which are especially useful if scale dials or indicators are retained. Electronic scale indicators can be fitted with connectors to allow quick change when required. The only problems occur with dual-solenoid valve controls such as fitted on most mixer discharge doors. These need an isolating switch to prevent both the BatchTron and the manual control from trying to act at the same time; both the “open” and “close” valves can be open at the same time, with unpredictable results. Also, a safety hazard results when the mixer can be started from an external switch if it is not fitted with a physical time delay relay and warning horn in the MCC; BatchTron incorporates these functions in its software and it is impossible to start the mixer from BatchTron without sounding the horn, as required by OSHA and other regulatory agencies.
Manual controls can be used, but check the important exceptions.
Moisture values can be entered from BatchTron’s moisture screen or automatically from remote sensors such as our AquaSense moisture sensor. The moisture in the aggregate makes up some of its weight, causing the actual batched weight of dry aggregate to be less than the desired target. BatchTron calculates this error and compensates for it based on the moisture value, resulting in new aggregate targets which are higher than the dry targets in the formula. Likewise, the water contained in all the aggregates is calculated and subtracted from the water target to give a new target which is less than the formula value. The result is better consistency from batch to batch and day to day because every batch conforms to the theoretical mix design; the only errors are caused by the normal batched weight variances and, of course, errors in the moisture values entered by hand.
Accuracy requirements of most concrete associations cannot be met without automatic moisture compensation (from sensors) on sand and other fine aggregates.
Other batching frequently asked questions – contact us directly for an answer.