Voltage Drop In The Supply; Shielding And Cable Routing - Balluff BML-S2C0-Q M6 Serie Notice D'utilisation

BML-S2C0-Q _ _ _ -M6 _ _ - _ 0-KA _ _ /KF _ _ /KA _ _-S284
Incremental Magnetic Linear Encoder
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Installation and connection (continued)
4.4

Voltage drop in the supply

While operating at 5 V, the operating voltage
must be 5 V ±5%. To avoid voltage drops in the
supply, we recommend using a regulated power
supply with sense input (Fig. 4-3).
If this is not possible or desired, integrate the
sense lines of the 12-wire cable parallel to +5 V
and GND (Fig. 4-4).
Fig. 4-3: Power supply with sense line
Fig. 4-4: 5-V power supply without sense line
Calculated voltage drop for BML sensor heads with 5 V
supply voltage, with 120 Ohm input resistance per control
channel:
Cable length Voltage drop in cable
5 m 0.1 V
10 m 0.2 V
15 m 0.3 V
20 m 0.4 V
Tab. 4-3: Voltage drop (BML-S...-Q61-...)
If operating with 10 to 30 V DC, the voltage may
not sink below 10 V. With a 10 V supply voltage,
we either recommend setting the power supply
to 10.5 V or not using cables that are longer
than 2 m.
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4.5

Shielding and cable routing

Defined ground!
The position measuring system and the control
cabinet must be at the same ground potential.
Shielding
To ensure electromagnetic compatibility (EMC), observe
the following:
– The cable shield must be grounded on the controller
side, i.e. connected to the protective earth conductor.
– When ducting the cable between the sensor, controller,
and power supply, it is important to avoid going near
high voltage cables due to interferences.
Stray noise from AC harmonics (e.g. from phase angle
controls or frequency converters) are especially critical
and the cable shield offers very little protection against
this.
Magnetic fields
The position measuring system is a magnetically coded
system.
It is important to maintain adequate distance between the
position measuring system and strong external magnetic
fields.
Cable routing
Do not route the cable between the position measuring
system, controller, and power supply near high voltage
cables (inductive stray noise is possible).
The cable must be routed tension-free.
Bending radius for fixed cable
The bending radius for a fixed cable must be at least 7.5
times the cable diameter.
Cable length
Max. cable length 20 m. Longer cables may be used if
their construction, shielding and routing prevent noise
interference.
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