Datasheet
DC 2--wire Models, continued
Refer to the following to calculate the bleeder resistance and the al-
lowable power of the bleeder resistor.
R
V
S
/(i
R
-- i
OFF
)(kΩ)
P>V
S
2
/R (mW)
P: The allowable power of the bleeder resistor. (The actual power
capacity of the bleeder resistor must be at least a few times as
large as the allowable power of the bleeder resistor.)
i
R
: Leakage current of Sensors (mA)
i
OFF
: Release current of load (mA)
The following resistors are recommended.
12 VDC (supply voltage): A resistor with a resistance of 15 kΩ maxi-
mum and an allowable power of 450 mW minimum
24 VDC (supply voltage): A resistor with a resistance of 30 kΩ maxi-
mum and an allowable power of 0.1 W minimum
Inrush Current
A load that has a large inrush current (e.g., a lamp or motor) will
damage the Proximity Sensor, in which case connect the load to the
Proximity Sensor through a relay.
PRECAUTIONS FOR AC OR DC 2-WIRE PROXIMITY SENSORS IN OPERATION
Connection
Model Connection Type Method Description
DC
2-wire
AND
(serial connection)
Load
Correct
The Sensors connected together must satisfy the
following conditions.
V
S
-- N x V
R
Load operating voltage
N: No. of Sensors
V
R
: Residual voltage of each Sensor
V
S
: Supply voltage
If each Proximity Sensor is not supplied with the
rated voltage and current, the indicator will not
be lit properly or unnecessary pulses may be
output for approximately 1 ms.
OR
(parallel connection)
Load
Correct
The Sensors connected together must satisfy the
following conditions.
Nxi
Load operating voltage
N: No. of Sensors
i: Leakage current of each Sensor
If the MY Relay, which operates at 24 VDC, is
used as a load for example, a maximum of four
Proximity Sensors can be connected to the load.
AC
2-wire
AND
(serial connection)
Load
Load
Load
V
s
100 V
Incorrect
Correct
If 100 or 200 VAC is imposed on the Proximity
Sensors, V
L
(i.e., the voltage imposed on the
load) will be obtained from the following.
V
L
=V
S
-- (residual voltage x no. of Proximity
Sensors) (V)
Therefore, if V
L
is lower than the load operating
voltage, the load will not operate.
A maximum of three Proximity Sensors can be
connected in series provided that the supply
voltage is 100 V minimum.
E2E2 E2E2