[?]: Hydraulic Pump and Valve

[nashama]

Hello !
In a simple hydraulic application the cylinder moves forward / backward, what is the usual practice in programming (S7) - Is the pump and valve activated together or a certain delay is to be observed before engaging the valve?
Like , is it ok to command "Q2.0" (HYDRAULIC PUMP) and "Q2.1" (VALVE) in parallel together?
Regards

[PLC_ITA]

there is'nt a fix rule. Usually is better to have a pump in run to have a correct pressure, and then open the valve

[nashama]

@ PLC_ITA: " ............. , and then open the valve"

1s will be good enough?
Regards

[Homeroid_BL]

Sure. Pump should run continously.

[nashama]

@ Homeroid_BL : "Pump should run continously."

But the pushing event takes place every 30min (or least 15min) ..... Is it advisable to keep the pump running?

I mean why can't we engage the pump when the pushing time is up and ofcourse after 1s energize the valve as well?

1s is not enough to build up the pressure you mean?

Regards

[Pong Qinaya]

It usually pump run continuously, if your pump START - STOP - START - STOP, your motor will damage soon

[Cameleon]

Hello,

I was an engineer that started up filterpresses.
Good practice will be to let the motor start up and run idle for about 2 sec.
After these 2 sec you can energize the valves.

If your hydraulic ram is onder pressure and you start up the motor and the valve at the same time.... i garantee you that you can replace your contactor/ relay within a year because of the burned contacts.
And after 5 years your motor if the quality wasn't too bad

Grtzz

[nashama]

Thank you very much for the response.

[hoangkhoang]

There's a normal way: should install a pressure switch check the outlet of hydraulic pipe. When pump ran and our pressure ok (depend on your setting in pressure switch) this signal will be sent to our PLC, then this is permissive for hydraulic station operate (opening valve).
Have a luck!
Brs!!!

[dorofteius]

From experience, as I work with this kind of things every day.
The pump, has a valve that let's the pressure out only whet it reaches a certain pressure.
When you give the command, the pump starts at full speed. It is no a problem making the presure fast, the
problem is after the valve that you are commanding stops(if the pump would not stop instantly it would breake everithing ).
Normaly at a pump that work's most of the time
has that overpresure valve. When it reaches the presure, the overpresure opens and it's just recirculing the oil
in the tank.
If you need something fast, the pump runs continously, but the delay is under a half of a second.(that depends on the speed of the pump).
If it is something slower, the valve run's about 5 to 10 seconds after to keep the pressure in the hose or plumming
instalation.
This thing's you can find on google.

I hope I was helpful, and please excuse the bad writing thing.