Voltage Drop In The Supply; Shielding And Cable Routing - Balluff BML-S Série Notice D'utilisation

BML-S _ B/C/E0-Q _ _ _ -M4 _ _ - _ 0-KA _ _ /KA _ _-S284
Incremental Magnetic Linear Encoder
4
Installation and connection (continued)
4.5

Voltage drop in the supply

If 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 (Figure 4-3).
If this is not possible or desired, activate the
sense lines of the 12-wire cable parallel to +5 V
and GND (Figure 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 (0.4 V with reference sensor)
20 m 0.4 V (0.5 V with reference sensor)
Tab. 4-4: Voltage drop (BML-S...-Q61-...)
If operating at 10...30 V DC, the voltage may
not drop below 10 V. At 10 V supply voltage, we
recommend either setting the power supply to
10.5 V or not using cables longer than 2 m.
12 english
4.6

Shielding and cable routing

Defined ground!
The linear encoder 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 linear encoder is a magnetically coded system. It is
important to maintain adequate distance between the
linear encoder and strong, external magnetic fields.
Cable routing
Do not route the cable between the linear encoder,
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.