Spool Calibration; Prerequisites - Danfoss PVED-CLS User Manual

ENGINEERING TOMORROW
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P3205 < P3209 < P3207 or P3205 > P3209 > P3207
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P3211 < P3215 < P3213 or P3211 > P3215 > P3213
9.3

SPOOL CALIBRATION

As per default, a PVED-CLS will boot-up in spool calibration service mode after a successful WAS calibration, if WAS
interface (i.e. P3244) is set to either analogue or CAN, has been completed. From here either the spool auto-calibration
routine from the Danfoss PLUS+1 SERVICE TOOL can be used or a manual spool calibration can be performed, using
the direct output control function.
The PVED-CLS shall be calibrated to the OSPE, EHi or EHPS valve in order to achieve optimum and consistent
steering performance in terms of auto-guidance precision and fast-steering performance.
A valve can be calibrated in more ways. Common for all the procedure is that the goal is to:
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Find the optimum minimum spool position set-points for closed-loop wheel position control
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Find the optimum minimum spool position set-points for open-loop flow control
Danfoss recommends using the direct spool control to find the optimal closed-loop dead-bands. When these have been
determined, a constant steady movement of the wheels relationship can be found, hence how many degrees the wheels
turn per second. This relationship is to be used as acceptance criteria, when designing the Auto-calibration parameter-
set.
Example:
Using direct output control, two closed loop dead-band values have been found (P3166 = -90; P3168 = 100), and a
constant steady movement of the wheels relationship has been measured (2° per second).
When designing the Auto-calibration parameter set, use the maximum closed loop dead-band value as your Spool
calibration - Initial spool position (P3802 = 100) and use the constant steady movement of the wheels relationship (2°
per second) for setting the following 3 parameters:
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Spool calibration - +/- turn range sweep (e.g. P3804 = +/- 2,5°, hence P3804 set to 25)
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Spool calibration - Max time for acceptable CL dead-band edge (e.g. P3806 = 3 seconds, hence P3806 set to
30)
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Spool calibration - Min time for acceptable CL dead-band edge (e.g. P3808 = 2 seconds, hence P3808 set to 20)
The acceptance criteria (P3806 and P3808) with a given range (P3804) can be decided. Having a narrower acceptance
criteria, gives a more precise dead-band calibration, but could potentially take longer time to tune.
9.3.1

Prerequisites

Prior to spool calibration, the wheel angle sensors shall be calibrated, the calibration counters and bit inverted copy for
WAS calibration should be updated and a sufficiently large signal to noise ratio shall be ensured (see chapter 9.1). Valve
calibration shall be done when the PVED-CLS is in service mode, either "Spool calibration" or "Direct output control".
62 | © Danfoss | August 2018 AQ00000211