Siemens SIMATIC FM 353, Manual

Page: 276 / 361

Description of Functions
9-76
FM 353 Stepper Drive Positioning Module
6ES7 353-1AH01-8BG0
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
rot 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
°
45
°
. The error “Rota-
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
− 45
°
+45
°
B
A
NIX
NIX − Zero pulse external
− (NIX center is synchronization point for rotation monitoring)
X − Permissible range for NIX
A − Following error trigger point on ro (after 1 rev. + 45
°
)
B − Following error trigger point on rotation − (after 1 rev. + 45
°
)
Fig. 9-10 Allowable range relative position for the external pulse