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how the proportional signal change with regards to

Hi.got two question

Q1 how dose the proportional signal for voltage controlled hydraulics change in regards to position on laser receiver for 12v-24v system?

Q2 changing sensitivity for hydraulics response change what aspect of the hydraulics signal for voltage controlled hydraulics

thanks

Before the answer is too broad, I would once again ask for that control system is used. The question was placed under the category Laser-matic. But the laser-matic has not voltage output usually. However, unlike in connection with the GS 506t system the controller is prepared to drive voltage conrolled valves. Proportional laser receivers are used in both systems.

Sascha

thanks sascha your explanation was really helpful.

i am now trying to connect single laser matic to test valve on desk. i am using page 89 (technical data) of laser matic manual to wire up.

in there pin F is referred as ""output circulation valve""

what type of valve connection is this pin referring to ?

is this output always active? as in the menu there is no option to select this valve type , only available options are on/off (PNP / NPN) AND PROP ,PNP.

is this pin referring to Denfos proportional valve type?

if not how can you wire Denfos valve to laser matic?

it would be good if i can have some wiring diagram explaining all the connections...as like you have for GS506 system.

thanks in advance

Hello Bojan,

The pin F is only needed when the machine has an additional valve to regulate the hydraulic pressure depending on the needs. Thus, if an output of the controller is activated - doesn’t matter if UP or DOWN - and a higher pressure at the height cylinders is required, this valve will be driven parallel to the levelling outputs in order to increase the oil pressure at the complete system.

Cause this valve typically switch between NO or MAX. oil pressure we only offer a ON/OFF PNP output.

If the pressure is not regulated load-dependent, this valve output is not needed.

The Laser-matic has no Danfoss standard output to configure. But using an additional electronic board it is very simple to convert the PNP (ON/OFF or Prop.) outputs for UP and DOWN coming from the Laser-matic to a voltage signal required from the Danfoss valves.

Sascha

hello Sascha

thanks for your response.

i got few more questions,

i was reading data sheet of my hydraulics valve, there they also mentioned the inductance and resistance of the coil.

but in laser matic i did not see any menu where i need to put these values.

so will the system automatically detect these settings?

is there some default value in the system?

how these values effect operation of my system if they are different to specified values?

please enlighten me

thanks

bojan

Hello Bojan,

there is no need to enter the coil resistance. But to have this data is a help to determine the maximum current which can flow over the coil.

Just an example:

You have a machine with 24V power supply and the coil resistance of your valve is specified with 30 Ohm.

Based on the formula

I (Current) = U (Voltage) / R (Resistor) you can calculate now

0,8 A = 24V / 30 Ohm

So 800mA is the current which could be needed to open the valve total. Typically the real current you need for “complete open” is a little bit less than this calculated max current.

That is the theoretical part.

In Praxis you bound the MIN and MAX current to the speed you like to have at the cylinder.

MIN-current should be the smallest possible movement at the cylinder anyway. So you can reach a precice fine control within a Millimeter.

The movement you like to reach with the MAX current you can see during the hydraulic setting procedure for the max current. You can see how the movement speed change by increasing the max current and set to its Maximum possible speed or limit it.

The default settings at proportional output is set to

MIN-current = 50mA

MAX-current = 1.30 A

All these settings and default values are listed and described at the parameter setting manual too.

Parameter_settings_Laser-matic_Version_4.78-2003_and_higher_EN.pdf

Sascha

However, first I would like to distinguish between the laser receiver sensitivity and sensitivity of the control system.

For the proportional laser receiver LS-3000 no external sensitivity adjustment is provided on the control system (Via CAN theoretically possible). The resolution the laser beam is measured during initialization of the receiver is always at the highest = 0.1 mm.If the beam can not clearly be detected (e.g. mirrors), the LS-3000 reduces its sensitivity automatically until it reaches a reliable measurement. How sensitive the control system react to the measured values or a change from set point is determined only by the sensitivity setting at the controller.

Basically, you can say that the control sensitivity is a kind of combination of dead band (no valve control) and proportional range (linear increase in the valve output, depending on the value within this range). There are, in laser-matic controller as well as at the controller for the GS-508, fixed stored tables (these are presented in the respective manuals).

An example: The sensitivity value 9 in the laser-matic corresponds to a dead band of 0.9 mm and a Proportional range of 12.7 mm. The result by a measured deviation will be as follows

  • e.g. 0.3 mm deviation = no control of the valves (since within the dead band)
  • e.g. 1.0 mm deviation = a valve control with very low current (at voltage control valves, with a correspondingly small change in voltage to Vcc ½)
  • e.g. 10 mm deviation = a valve control with a higher current (at voltage control valves, with a correspondingly high change in voltage to Vcc ½)

What the respective current or voltage is at a certain deviation is actually determined via the hydraulic calibration, were the minimum current (voltage) and maximum current (voltage) will be fixed.

Also here an example: If I set the minimum current (the cylinder make the smallest possible movement) to 0.25 Amp. and the max. current to 1 Amp. the valves controlled from 1% (0.25 A) up to 100% ( 1A), over the proportional band range of 12.7 mm (see our example above).

Same with voltage controlled valves (Danfoss).

Vcc ½ (12 V @ machines with 24V power supply or 6V @ machines with 12V power supply) means no reaction at the valves. If during the hydraulic calibration a minimum output voltage set to e.g. 12,5V (for UP)/11,5 V (for DOWN) and 18V/8V for max. output voltage the valves will be controlled within the proportional band from 1% (12,5V/11,5 V) up to 100% 18V/8V.

Maybe the attached graphic helps to make it a bit clearer.

Sascha

In addition to Sascha's reply, our laser-matic has a special feature where the user can switch off the pre defined sensitivity (1 to 10) and manipulate his own combination of dead band and proportional band as per his application. This has been a really a very handy feature with the CLS3000 in our agriculture market.

thanks all for information. it was really helpful.