Modular Blocks for PLC Applications

http://www.actel.com/documents/PID_AN.pdf

Thank you for the link.

However, I think I wasn't clear enough: I need to regulate output voltages in the O- 300 DC Volts range with a max current supply of 60 Amps

I still think basing from my own experience for this type of application, the use of PLCs still an overkill. Processes still the same, although one may label it as "state of the art", with the mere presence of PLCs in the circuit..

I want to control and protect everything with a PLC

A PLC can turn things on and off and run sequences using knowledge you build into the system but it won't be ideal for "protecting everything".

Most PLC's only provide very basic forms of input or output device. You will have to come up with some appropriate form of signal conditioning for each of the power supplies that you mentioned so that you do not exceed the range or accuracy of your input device. While this may sound fairly simple, it will take some work to make sure the chosen equipment will work as you need it to work. You will have to know just how accurate it has to be and how much error (tolerance) you can stand. And you may also need to have periodic self tests to make sure it is working as expected.

You may be able to achieve a modular arrangement or even buy something already made that will serve your purpose. As for "Plug and Play" you may be in for a disappointment. You will have to be a lot more specific.

A PLC may do the job but you should know that they are somewhat limited as to response time. Depending on what you use, it could take up to 20 mSec or so before it will be in a position to respond to an input. Is that going to be fast enough?

Yes it will be fast enough. Now it is controlled with conventional timers and a print, used for controlling motors.

It is a stage in the fabrication of Lead Acid batteries, called "formation".

It serves to make the battery ready. or better to condition the plates to give full capacity. This cycle has to be performed within a temperature, lower than 70 degrees Celsius. When the temperature runs too high crystals are formed on the plates and take down the capacity because the "spongy" plates cover with these.

In practice about 10 batteries are put in series to correspond with the available rectified and regulated grid.

In this process the voltage and current are controlled.

The idea is to work within a 24 hour time frame. Assembling the batteries in box- transportation and connecting them on benches or transport belt and work from there.

In total about 3000 batteries a day are to be formed. (300 stations)

Depending on the destination, they depart or wet, or dry to the distributor or OEM client (e.g.automobile plants)

My thougths went to Semikron components Thyristor and Firing blocks.

Just a suggestion. Use your controller for monitoring and determining actions and use a servo motor operating an auto-transformer to adjust your AC voltage input to a fixed DC power supply. This would give you what you require while keeping the hardware simple. The programming will be a little complex at points but should not be that difficult.

Thank you for the suggestion.

That is 300 60 amps servo autotransformers/ transformation/place/work/

way above the budget. Now it is done with thyristors and soft starter circuits and I want to take it one step further. The division with 3000 batteries in it needs to be controlled by a few persons.

For a formation process of e.g. a car battery of 12 volts 70 Ah - now is about 2,5 to 3 times the energy required per battery. (thus approx.200 Ah) Also this ads to cost price.

The 300 stations need sometimes different individual settings, that have to be controlled and monitored from 1 central point - with continuous adjustments and alarms.

I agree with you for a small scale project, but battery manufacturing is a tough bizz.

Yes, back in the early 70s we build some 20 units of this BFRs for a local battery manufacturer in the Phil. The finished Battery Forming Rectifier unit basically is similar in functionality to a high powered phase controlled light dimming circuit. Except for the combinations of high capacity diode-SCR in a polyphased configuration used in the output stages. The modified power output stage configurations was due to a much higher current specifications ordered, as well as due to the raw power being derived from a 3-phase source. All controls and logic circuitry used were derived / copied from a comparable op-amp based logic and switching circuitry design samples as found in the old GE Thyristor semiconductor manual. I believed PLCs were still not available nor popular during those days!

I would suggest looking at using DC Variable Frequency Drives (VFD).

The PLC can easily be used to control the VFD output via a 4-20mA and/or 0 -10VDC loop.

The units are modular and can easily be installed and/or replaced in the event of a failure.

They are also very tunable. (Step control, variable linear, ramp rate, etc.)

Contact the technical department of the VFD manufacturer of your choice and ask if they have a machine that can do what you need.

Thank you very much. I am afraid that a VFD is "over-qualified". It may work, but normally it has a lot more features and if the VFR basic job (interact with variable frequency) will give me some advantage I doubt. My goal is to work with one or two Half bridge configuration(s) with Thyristors, IGBT or Mosfets to do the job.

In the desired power range SEMIKRON comes with SEMIPACK, SEMIPONT and MINISKiP modules, but help from them for the periphericals stays away so far.

As far as the (phase angle- Thyristors) and (saw tooth- IGBT) power control of course these can work.

The "interface" to make it work with PLC signals is the missing link till now.

I appreciate your answer. D

I want to control and protect everything with a PLC... / ...way above the budget. ◄ you said
... afraid that a VFD is "over-qualified". / TEST: way above the budget. ◄ you said
The output needs no smoothing out filters. ◄ consider the term detectioncircuitry F;T
300V,60A is quite near device limits usually the best performance is at 10-30% of that OTHERWISE you need to be very accurate
i donno abou'thi'stuff in detail don't fail to hopefully stare at me - i just read the thread