Proximity Sensors Technical Guide
●
Wiring Considerations
AND/OR Connections for Proximity Sensors
Note: When AND/OR connections are used with Proximity Sensors, the effects of erroneous pulses or leakage current may prevent use. Verify that there are no
problems before use.
Model
Type of
connection
Connection
Description
DC 2-Wire
AND (series
connection)
Keep the number of connected Sensors (N) within the range of the following
equation.
V
S
- N
×
V
R
≥
Operating load voltage
It is possible, however, that the indicators may not light correctly and error
pulses (of approximately 1 ms) may be generated because the rated power
supply voltage and current are not supplied to individual Proximity Sensors.
Verify that this is not a problem before operation.
OR (parallel
connection)
Keep the number of connected Sensors (N) within the range of the following
equation.
N
×
i
≤
Load reset current
Example: When an MY (24-VDC) Relay is used as the load, the maximum number
of Sensors that can be connected is 4.
AC 2-wire
AND (series
connection)
<TL-NY, TL-MY, E2K-
@
MY
@
, TL-T
@
Y>
The above Proximity Sensors cannot be used in a sereis connection. If need-
ed, connect through relays.
<E2E-X
@
Y>
For the above Proximity Sensors, the voltage VL that can be applied to the
load when ON is V
L
= V
S
- (Output residual voltage
×
Number of Sensors), for
both 100 VAC and 200 VAC.
The load will not operate unless V
L
is higher than the load operating voltage.
This must be verified before use.
When using two or more Sensors in series with an AND circuit, the limit is three
Sensors. (Be careful of the VS value in the diagram at left.)
OR (parallel
connection)
In general it is not possible to use two or more Proximity Sensors in parallel
with an OR circuit.
A parallel connection can be used if A and B will not be operated simulta-
neously and there is no need to hold the load. The leakage current, however,
will be n times the value for each Sensor and reset failures will frequently oc-
cur.
("n" is the number of Proximity Sensors.)
If A and B will be operated simultaneously and the load is held, a parallel con-
nection is not possible.
If A and B operate simultaneously and the load is held, the voltages of both A
and B will fall to about 10 V when A turns ON, and the load current will flow
through A causing random operation. When the sensing object approaches B,
the voltage of both terminals of B is too low at 10 V and the switching element
of B will not operate. When A turns OFF again, the voltages of both A and B
rise to the power supply voltage and B is finally able to turn ON.
During this period, there are times when A and B both turn OFF (approximately
10 ms) and the loads are momentarily restored. In cases where the load is to
be held in this way, use a relay as shown in the diagram at left.
Vs
-
-
+
+
Load
N : Number of Sensors that can be connected
V
R
: Residual output voltage of Proximity Sensor
V
S
: Power voltage
-
+
+
Vs
Load
N: Number of Sensors that can be connected
i: Leakage current of Proximity Sensor
X
1
X
1
X
2
X
2
V
L
V
S
V
S
V
S
V
S
≥
100V
Load
Load
Load
Load
(A)
(A)
(B)
(B)
X
1
X
1
X
2
X
2
Load
A
C po
w
er supply
voltage Vs
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