ASO Safety Solutions INDUS classic 74-312, Operating Manual

20

Inductive signal transmission system

9 

Error diagnosis

Only the 

green

 LED may illuminate if the supply voltage has been correctly connected If one of the 

red

 LEDs illuminate, there is an error in the system which can be pinpointed with the aid of the LED

LED 

Error

Error correction

LEDs are not 

illuminated

The supply voltage is missing, too 

low or has been connected incor-

rectly

Check connections and supply voltage:

-  24 V AC/DC at terminal 

24 V AC/DC

 or

-  230 V AC at terminals 

L1 and N

Tolerance range: ±10%

A single red LED 

is illuminated

Contact edge(s) not connected, 

connected incorrectly or faulty

-  Check the connections of the corresponding 

contact edge (squeezed or brittle supply 

lines, etc)

-  Check safety contact edge(s)* 

One of the contact edge connections 

is not being used

Any contact edge connections that are not 

being used must be permanently bridged 

using one of the supplied 82 kΩ resistors

Both of the red 

Transmit

 LEDs 

are illuminated

The transmission line is faulty or has 

been installed incorrectly

-  Observe the mech assembly instructions 

(INDUS signal transmission system)

-  Check transmission coil cores for abrasion 

-  Check cable loop; make certain that both 

transmission coil cores are in the cable loop

-  Check cable / gate leaf contact points

-  Check supply voltage**

Contact edge(s) not connected, 

connected incorrectly or faulty

-  Check the connections of the corresponding 

contact edge (squeezed or brittle supply 

lines, etc)

-  Check safety contact edge(s)* 

* If the error is not related to the system’s wiring, the proper function of the electronics can be tested 

by connecting an 82 kΩ resistor to each of the SCE inputs on the INDUS classic 74-312 electronic 

evaluation system (terminals 

Stationary Opening

or 

Closing

) and to the travelling coil core (connec-

tions 

O

 and 

C

) If the electronics work perfectly after performing the test, the safety contact edges 

must be checked using an ohmmeter To do this, the respective connection on the SCE for the 

electronic evaluation system or for the travelling coil core must be disconnected and connected to an 

ohmmeter

The resistance must be 82 kΩ ±500 Ω when the safety contact edge is inactive and must not exceed 

500 Ω when it is active

** If both of the LEDs for the travelling SCEs (

Transmit Opening

 and 

Transmit Closing

) illuminate, there 

is an error in the inductive signal transmission system The most frequent causes of these errors are 

bad coil core connections, incorrectly installed cable system components (see INDUS signal transmis-

sion system assembly instructions) or an impermissibly low supply voltage

The maximum resistance value of the cable loop must not exceed 3 Ω The resistance value can 

be measured by disconnecting the steel cable from the ground terminal and then measuring the 

resistance between the end of the steel cable and ground terminal