Instruction Manual PSx3xxEC
26
4.3
Response of drive in case of block
If during a run due to load the speed falls below the threshold parameter of 30% of
the selected maximum speed (SDO #201A) for longer than 200 msec (SDO #201B),
the device detects blockin
g, aborts the run and sets the ‘positioning error’ bit (here the
default values are given). The drive from now on stands with the selected holding
torque (SDO #202B).
New run commands can then be transmitted with no further steps to take, i.e.
transmitting a target value (SDO #2001) starts a new run.
An exception is in the case of PDO transfers, if the run should go to the same target
than before. In this case, deassert the release (bit 4 of the control word) and assert it
again
. Bit 2 (‘transfer target value’) has to be set at the same time. The drive then
moves on when the release bit is being asserted again.
In the state “pre-operational” deasserting and asserting the release bit does not cause
a new run. The (old or new) target value has to be sent explicitely by setting SDO
#2001.
4.4
Response of drive in case of manual displacement (readjustment)
If after a correctly finished positioning run during standstill the PSx3xx is displaced by
external force opposite to the loop direction and the release bit (bit 4 in the control
word) is set and the readjustment function (SDO #2047) is enabled, the device will
attempt to reach the previously transmitted target value once again (readjustment).
The device does not attempt to readjust if rotated in the loop direction; it merely sets
bit 11 in the status word (
‘manual displacement’) and resets bit 0 (‘target position
reached
’). If the loop run is disabled (SDO #201F is 0), the drive readjusts the
position in both directions.
If the manual displacement occurs, when the motor supply voltage is not present or
too high (bit 4 in the status is not set), the readjustment starts automatically when the
motor supply voltage is again in the allowed range.
After a stop command the drive readjusts the position not before the next positioning
run.
Deasserting the release bit and/or disabling the readjustment function can completely
disable the readjustment process.
4.5
Calculating the absolute physical position
The PSx3xx actuator includes an absolute measuring system with measurement
range of 256 rotations. In order to avoid an overflow when the drive is switched off
and moved by an external force, the user can only command positionings in the range
of 250 rotations. Thus the upper as well as the lower 3 rotations of the measurement
range are inaccessible.
The mapping of the desired positioning range to the physical positioning range is
done
with the help of the parameter ‘upper mapping end’ (SDO #2028).
In the delivery state, the drive is at position 51200, the upper limit switch is set to
101200 and the lower limit switch is set to 1200, yielding a positioning range of ±125
rotations (±50000 increments). So if the desired positioning range doesn’t exceed
±125 rotations, in delivery state none of the following actions to adjust the positioning
range have to be taken.
