SIXpack 2 – Manual (V1.10 / January 29
th
, 2010)
24
search should be set. To avoid errors caused by vibrations of the motor during fast reference search, de-bouncing
of the reference switch FilterSwitch (s. CMD $15 P5, Bit7) should be activated, too, and the mask for reference point
de-bouncing (s. CMD $16) should be programmed with an applicable value.
vmin
(always used with predivider
div
i
set to 3) will be used while exactly locating the reference switch. The fastest possible
vmin
will be choosen
automatically when its value is set to 0.
Stop
Left
Stop
Right
Ref
e
re
n
ce
S
to
p
R
poslimit
positive
direction
motor
re
fe
re
n
ce
p
o
int
n
u
ll
p
o
sition
n
u
ll
p
o
int
-o
ff
se
t
traveller
te
stn
u
llr
a
n
g
e
Graphic assumes null-left Flag is set and null point offset is positive(s.
CMD $15
).
In this configuration the reference switch is reliably closed at position null.
Note: testnullrange >= width of reference switch!
settings: null point-offset, poslimit -> CMD $15
testnullrange -> CMD $18
The reference switch defines the zero position. The zero position can be moved further into the switch
using the
nulloffset
setting. If
testnullbit
is set it must be active at the end of
T0
and the delay time of the
filter.
Activation of the switch is only allowed in the
testnull
range to
testnull
around the zero position. If you
reference to the edge of the switch and never exceed the zero position the
testnull
range can be choosen
around 1-2 fullsteps * 16. In all other cases you must choose it at least slightly larger than the active area
of the reference switch or half of this for
nullcenter
motors.
The reference search requires proper
poslimit
(0..0x7FFFFFFF) settings! For cyclic axis you must set
poslimit
to the number of microsteps per revolution, for linear axis it should cover at least your whole intended
driving range to avoid unintended or interrupted reference drives.
6.2.1.6
Problems with fast Search for Reference
The fast search for reference will function properly only if CMD $15 and $16 are set correctly, especially those for
the reference switch. Also is it sensitive to noise pulses in the wiring of the reference switch – should the fast
reference search stop abruptly, anti-noise measures have to be taken for the reference switch input.
6.2.1.7
Interlacing of Requests
Requests must not be interlaced. Each request should wait for the response of the SIXpack 2 before
transmitting a
new command. However a delayed response with RS 232 may be outstanding in parallel.
6.2.1.8
Default Values
For testing purposes here is a list of default values for motor parameters:
clkdiv
=5;
div
=2;
// 26 kHz microstep-frequency
vstart
=5;
// starting with 254 Hz (should be >=8)
amax
=128;
vmax
=511;
// increments v by 128/16=8 each 2 ms
vmin
=4;
vrefmax
=100;
// 102 Hz / 5086 Hz for reference drive
poslimit
=400*16;
// 400 full- = 6400 microsteps/revolution
testnullrange
=15*16;
// ignore switch in range –240 ... 240
Peak current=128;
// define 100% curr. control as 400 mA
