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This data indicates the Delta Error compared to previous homing, with this value you can easily check if the encoder is good or is broken.

Procedure:

1. execute an homing ¹⁾
2. move the axis in manual mode many times back and forward
3. then, without turning off the machine, execute the homing
4. the second homing will give an “important” meaning to this number: it will inform us how much is the offset of the count compared to the actual physical position of the machine
5. if the encoder is OK, this offset must be = 0
6. then, in reality, this number probably won't always be just 0 due to the tolerance of the limit switch used to execute the homing
7. if you repeating the homing for several times, you will be able to realize if the number highlights a faulty encoder, or an error given by the tolerance of the limt switch
8. a small repetitive error, evidence the tolerance of the limit switch
9. a big error, show the problem to the encoder

192.168.0.253

A positioning axis, with motor controlled by inverter, is managed with the following digita commands of ON/OFF type:

Example:

• AON to the Start ⇒ Forward output = ON
• RON = SET - Slowdown measure ⇒ Slowdown output = ON
• AOFF = SET - Inertia measure ⇒ Forward output = OFF

When the Forward output of movement = OFF, because of its weight, the axis will continue the movement, cover through the Inertia space, from the ION point to SET point ¹⁾.

In the RON moment, analog output is less than V-.
To get a correct positioning, it is necessary that the axis can decelerate and discharge all its kinetic energy, before getting to the ION point…..

• if this happens
• if the weight of the axis does not change and does not swing the axis
• if the scroll guides do not vary their friction

….the axis will position correctly to the SET.

X-Y-Z-H axes have a constant weight, consequently their space of Inertia is then normally “constant”.

For the W axis is different, because of the different weight of the stone blocks that are put on top of it, the Inertia space may be variable, especially if the reduction ratio between engine and mechanics is not very high.
To remedy an ineligible reduction ratio, it will no longer be enough to control the axis with normal Slowdown and Inertia commands, instead you will need to use the Pulses Technique.

After commanding the axis to slowdown the speed, from the RI point, the axis command is execute using small voltage pulses, setting the following parameters:

• PULSES ENABLE PW-32 = 1
• APPROACH MEASURE PW-33 = xxxxx
• PULSE LENGTH PW-34 = xxxxx
• PULSES SPAN PW-35 = xxxxx
• PULSES NUMBER PW-36 = xxxxx
• PULSE AMPLITUDE PW-37 = xxxxx

The instrument, after every pulse, check that the count has arrived at the scheduled SET.
When the count arrived at the SET value, the pulses end.
In this mode, the adjustment will transform….

• from “open-loop”
• to a kind of “closed-loop”

….as is normally done to command:

• closed-loop vector inverters with feedback from encoders
• or Brusless Drivers

The calibration is simple. It only takes a little time to repeat the tests several times to see if the system is stable:

• adjust the sensitivity of the analog control of the inverter input, as low as possible, cheking that it does not become sensitive to electromagnetic interferences
• initially program the voltage value of the pulse or PULSE AMPLITUDE PW-37 = 0
• program the SLOWDOWN space PW-07 with high value
• start a positioning, the axis will stop space before you get to the SET
• at this point:

  • program the PULSES SPAN value PW-35 to an high value, for example 2 seconds
  • program the voltage value PULSE AMPLITUDE PW-37 and of PULSE LENGTH PW-34, minimum possible but sufficient to move the axis ¹⁾
  • program the PULSES NUMBER PW-36 to an high value, for example 999
• repeat positioning, will happen then that axis after slowing down, every two seconds will make a “small” advance
• at this point:

  • gradually decrease the PULSES SPAN value PW-35 until the axis moves continuously
  • than, gradually decrease the SLOWDOWN space PW-07 ²⁾
• Gradually you will see, in the final positioning phase, slow down in a short space and then finish the placement harmoniously, perfectly on programmed SET, with a block of stone, or without ³⁾.

Active function with parameter PG-34 = 1. Operating sequence:

1. Before handling the W or H axes, the O63 output of the hydraulic control unit is activated
2. The Hydraulic brakes (wedges) are portrayed from the resting position (normally pushed by a spring in the axle locking seat)
3. When wedges are fully portrayed, they activate the input I70
4. The W or H axes move

By enabling the Backlash Recovery you can achieve placements with higher accuracy.

	A	Positioning	Forward
	1		Without backlash recovery	PX-11, PY-11, PZ-11, PW-12, PH-13	0
	2		Backward backlash recovery		2
	3		Forward backlash recovery		1
	B		Backward
	4		Without backlash recovery	PX-11, PY-11, PZ-11, PW-12, PH-13	0
	5		Forward backlash recovery		1
	6		Backward backlash recovery		2
	Q.min	Measure	Minimum	PX-26, PY-26, PZ-26, PW-25, PH-26
	Q.p.		Positioning
	Q.max		Maximum	PX-25, PY-25, PZ-25, PW-24, PH-25
		Stretch of path space	at the work speed
			at slow speed
			for inertia

See following instructions:

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