Siemens SIMATIC FM 353 Manual page 276

Description of Functions
Function description
The external zero pulse is used as described below to monitor the motor rotation
as specified in controlled operation (see Figure 9-10)
S The first NIX received synchronizes rotation monitoring.
S The first NIX must arrive within the period elapsing during two stepper motor
rotations + 45°. Otherwise, the "Rotation monitoring" error message will be trig-
gered.
S With every further NIX received, the system verifies whether the current pulse
output of the stepper motor is within a window n
360
tion monitoring" is triggered by the occurrence of NIX edges which are outside
the allowed window.
S With every FM cycle the system verifies whether the pulse output is outside a
window " (360° + 45°) since receipt of the last NIX. Positioning outside this
allowable window also triggers the "Rotation monitoring" error.
S Stepper motor rotation without a specified setpoint value likewise triggers a
"Rotation monitoring" error in response to the NIX edges caused by the un-
wanted rotation. This occurs whenever the previous setpoint position falls within
the range outside the allowable window for the NIX edges. No error is triggered
if the previous setpoint position is within the admissible window as there is no
way of distinguishing between oscillation on a NIX edge position on account of
a fault or full motor rotation.
S Rotation monitoring is automatically discontinued whenever the synchronization
mark is passed over in the "Reference point approach" operating mode, and the
function "Retrigger reference point approach" is executed.
X − Permissible range for NIX
A − Following error trigger point on rotation + (after 1 rev. + 45°)
B − Following error trigger point on rotation − (after 1 rev. + 45°)
NIX − Zero pulse external
− (NIX center is synchronization point for rotation monitoring)
Fig. 9-10
9-76
−45°
B
NIX
A
+45°
Allowable range relative position for the external pulse
"45
°
X
FM 353 Stepper Drive Positioning Module
. The error "Rota-
°
6ES7 353-1AH01-8BG0