Press automation with EASY

[nazcal]

Hi all,

my customer has a newspaper printing machine. It has spraybars in the units. Now they're adding some new units with brushes. And the brushes are rotated by motors. These motors are 110VDC, .91A and are controlled by variable transformers. There are 24 units (3 towers) and it is hard to adjust all them during printing. I want to add a motorized variable transformer for each tower. I have 0-10VDC press speed reference and I think to add a feedback potentiometer for each transformer. Each transformers motor will be operated by two relays, up and down. Is it possible to do this with EASY822-DC-TC? I used EASY series before but never used the analogue inputs. Thank you in advance.

[Mr. Spok]

Hello,


what do you want to do? Do you want to synchronize the speed of the brushes with the speed of the paper?


Regards Jan

[nazcal]

Hello,


what do you want to do? Do you want to synchronize the speed of the brushes with the speed of the paper?


Regards Jan

Exactly. As I said I have 0-10V speed reference and when the press starts the variable transformer's motors will start via relays. When the feedback voltage from the potentiometer of each transformer reaches speed reference the relay for this motor will go off. So we have two relays for each motor. One of them is "up" and other one is "down" relay. Its a simpe design but cheaper. Thank you Jan.

[Mr. Spok]

Hello nazcal,

yes you can use one EASY 822-DC-TC for your project.

Have you more informations over the speed-signal and the transformer-feddback

0-10V = 0-??? m/min paper-speed  ?

0-10V = 0- m/min brushes-rotations-speed ?

In the appendix is a little example-programm to regulate a transformer-adjust-motor with a 3-point-step-regulator with dead-zone and gain for the pulse-lenght.

You must adapt the scailing-values to your project.


Regards Jan

[nazcal]

Thank you again Jan.

0-10V = 0-30000 cph (copies per hour) and for motorized variable transformers feedback reference I think to build my own 10V power supply. Or to use standard 12V PS.

The machine has 3 motors (125HP) and three drives. One of them is master and this drive generates 0-10V speed reference for slave drives, spraybars etc. For example the machine is working and the speed reference is 4V which means that the machine runs with %40. The "up" relay for each motor is on. When the feedback voltage of each motor reaches 4V its "up" relay will go off. If the voltage is over 4V the "down" relay will go on and stabilize voltage.

[Mr. Spok]

Hello nazcal,

how fast must be the regulation, or how long needs the motor at the transformer to drive from 0% to 100%.


Regards Jan