close loop whith step motor and encoder

Hello, I read in several places that one of the advantages of linuxcnc is its ability to generate a closed loop between the stepper motor and encoder. Two weeks I've been looking for ways to generate this but can not find how. The only thing I could do is control the motor and reading of the encoder, but I can not find how to close the loop. I've tried using PID, not knowing if I got what it takes and the fedback PID positicion equals the engine, repeating that I'm not sure if I'm doing well. I managed to make my code attempt with a little bit of information on the web and carefully reading each book, I hope someone can help me please, and sorry for my English writing.

# Generated by stepconf at Fri Jan 25 09:34:03 2013
# If you make changes to this file, they will be
# overwritten when you run stepconf again
loadrt trivkins
loadrt [EMCMOT]EMCMOT base_period_nsec=[EMCMOT]BASE_PERIOD servo_period_nsec=[EMCMOT]SERVO_PERIOD num_joints=[TRAJ]AXES
loadrt probe_parport
loadrt hal_parport cfg="0x378 out "
loadrt encoder num_chan=1
loadrt pid num_chan=1
loadrt stepgen step_type=0,0,0

addf parport.0.read base-thread
addf encoder.update-counters base-thread
addf stepgen.make-pulses base-thread
addf parport.0.write base-thread


addf encoder.capture-position servo-thread
addf stepgen.capture-position servo-thread
addf pid.0.do-pid-calcs servo-thread
addf motion-command-handler servo-thread
addf motion-controller servo-thread


setp encoder.0.position-scale 2500.00
addf stepgen.update-freq servo-thread
net spindle-cmd <= motion.spindle-speed-out
net Xpos-fb => pid.0.feedback
net xoutput <= pid.0.output


net enc0A encoder.0.phase-A <= parport.0.pin-10-in
net enc0B encoder.0.phase-B <= parport.0.pin-12-in

net Xpos-fb <= encoder.0.position

net estop-out => parport.0.pin-01-out
net xstep => parport.0.pin-08-out
net xdir => parport.0.pin-14-out
net xenable => parport.0.pin-17-out

setp stepgen.0.position-scale [AXIS_0]SCALE
setp stepgen.0.steplen 1
setp stepgen.0.stepspace 1
setp stepgen.0.dirhold 40000
setp stepgen.0.dirsetup 40000
setp stepgen.0.maxaccel [AXIS_0]STEPGEN_MAXACCEL
net xpos-cmd axis.0.motor-pos-cmd => stepgen.0.position-cmd
net xpos-fb stepgen.0.position-fb => axis.0.motor-pos-fb
net xstep <= stepgen.0.step
net xdir <= stepgen.0.dir
net xenable axis.0.amp-enable-out => stepgen.0.enable

#set PID output limit to /- 1.00
setp pid.0.maxoutput [AXIS_0]MAX_VELOCITY

# establecemos los parametros los cuales vendran del archivo ini
setp pid.0.Pgain [AXIS_0]P
setp pid.0.Igain [AXIS_0]I
setp pid.0.Dgain [AXIS_0]D
setp pid.0.bias [AXIS_0]BIAS
setp pid.0.FF0 [AXIS_0]FF0
setp pid.0.FF1 [AXIS_0]FF1
setp pid.0.FF2 [AXIS_0]FF2

#deadband should be just over 1 count
setp pid.0.deadband [AXIS_0]DEADBAND

#posotion comand signal
#net xpos-cmd axis.0.motor-pos-cmd =>pid.0.command
net xpos-fb axis.0.motor-pos-fb => pid.0.command

#axis enable signals
net xenable axis.0.amp-enable-out => pid.0.enable

net estop-out <= iocontrol.0.user-enable-out
net estop-out => iocontrol.0.emc-enable-in

loadusr -W hal_manualtoolchange
net tool-change iocontrol.0.tool-change => hal_manualtoolchange.change
net tool-changed iocontrol.0.tool-changed <= hal_manualtoolchange.changed
net tool-number iocontrol.0.tool-prep-number => hal_manualtoolchange.number
net tool-prepare-loopback iocontrol.0.tool-prepare => iocontrol.0.tool-prepared