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.

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 series connection. If need-

ed, connect through relays.

<E2E-X

@Y>

For the above Proximity Sensors, the voltage VL that can be applied to the

× Number of Sensors), for

both 100 VAC and 200 VAC.

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

-

+

+

Vs

Load

N: Number of Sensors that can be connected

i: Leakage current of Proximity Sensor

≥ 100V

Load

Load

Load

Load

(A)

(A)

(B)

(B)

Load

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