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3.4.7
Power Supply and STO Connection
3.4.7.1
Supply Connection
* For compliance to EMC surge immunity, an external capacitor must be added between +Vlog and GND. The capacitor
shall be of 100µF minimum, rated for the logic supply voltage.
**An external electrolytic capacitor may be added between +Vmot and GND, to help reduce over-voltage during load
braking/ reversals. See paragraph 3.4.7.2 for details.
3.4.7.2
Recommendations for Supply Wiring
The iPOS80x0 BX always requires two supply voltages: Vlog and Vmot.
Use short, thick wires between the iPOS80x0 and the motor power supply. Connect power supply wires to all the
indicated pins. If the wires are longer than 2 meters, use twisted wires for the supply and ground return. For wires longer
than 20 meters, add a capacitor of at least 4,700μF (rated at an appropriate voltage) right on the terminals of the
iPOS80x0.
It is recommended to connect the negative motor supply return (GND) to the Earth protection near the power supply
terminals.
3.4.7.3
Recommendations to limit over-voltage during braking
During abrupt motion brakes or reversals the regenerative energy is injected into the motor power supply. This may
cause an increase of the motor supply voltage (depending on the power supply characteristics). If the voltage bypasses
84V, the drive over-voltage protection is triggered and the drive power stage is disabled. In order to avoid this situation
you have 2 options:
Option 1. Add a capacitor on the motor supply big enough to absorb the overall energy flowing back to the supply.
The capacitor must be rated to a voltage equal or bigger than the maximum expected over-voltage and can be sized
with the formula:
where:
U
= 84V is the over-voltage protection limit
MAX
U
is the nominal motor supply voltage
NOM
Technosoft 2019
Figure 3.22. Supply connection
×
2
E
≥
C
−
2
U
MAX
26
M
2
U
NOM
iPOS80x0 BX-CAN/-CAT Technical Reference
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