Logo! 230RC - output always on

Hi,

I have a Logo! 230RC + an additional module installed. Attached there is the program it should execute: it controls the stairs lights of a building.

The problem is that the output Q3 sometimes (it seems randomly) is kept on: on the display the output is correctly shown as off, following the programmed logic, but the lights are lit.

It has appened a couple of time and we where able to reset its behaviour by turning off and on the program. This time we haven't found a workaround.

Thanks for any help.

Matteo

Hi Helmut,

thanks for your answer, and sorry for my late reply.

unknown user

Use additional in rush current limiter with the right specification at any relay output you have connected such lamps.

 I have no idea what a inrush current limiter is (I can imagine) and how to calculate the righr specification for it: we have on Q3 output 12 led bulbs (model: Osram CL P 25 (M3) E27) with these specifications:

Power: 3.5 W, Volt: 100-240V, freq: 50/60Hz, current: 33mA

Can you suggest me the right specifications or the way I can calculate them?

Thank you,

Matteo

HI

Try to disconnect the load from Q3 and check if Q3 is switching ON/OFF according to the logic if it is not working fine as already mentioned it must be broken.

Second you must use protection (current,voltage) for your circuit to keep both LOGO and the load safe! by considering how much VA  LOGO outputs can tolerate and do the same to the other sections of the circuit.

r.ethernet

HI

Try to disconnect the load from Q3 and check if Q3 is switching ON/OFF according to the logic if it is not working fine as already mentioned it must be broken.

Second you must use protection (current,voltage) for your circuit to keep both LOGO and the load safe! by considering how much VA  LOGO outputs can tolerate and do the same to the other sections of the circuit.

 HI,
probably Q3 is broken. I will try to implement the same program on another exit, but before I would like to know how I can protect the exits.

Unfortunately I have no idea how to do it. This is the manual of Logo 230R and at page 105 start the technical data.

Any help on what to put in the circuit and how to calculate the right spec?

Thank you,

Matteo

Hi matteo

The meaning of protection is to use some protective devices (fuse,mcb,and any ther protection based on  your schematic)

For example the output can carry max. 8A continuously and must be sure that the current stays in normal range.

To get a better answer for your question it will be helpful if you post here the schematic of yours.

r.ethernet

To get a better answer for your question it will be helpful if you post here the schematic of yours.

 As I wrote before:

m_nobili76

we have on Q3 output 12 led bulbs in parallel  (model: Osram CL P 25 (M3) E27) with these specifications:

Power: 3.5 W, Volt: 100-240V, freq: 50/60Hz, current: 33mA

 Hope it helps

Helmut_13

Hi,

basically I belive the Q3 is damadged becaus of the high inrush current.

I Internet there are information, that a LED lamp generates a current 1700 time higher then normal. In your case:

30mA per LED * 1700 = 51A for one LED

Google for "inrush current limiter"

You can find a lot of information.

In any case you should change the LOGO! because this relais output is definitly damadged. Or if you have an other unused output then change to this. But don't forget to use the additional inrush current limiter. Otherwise the second output may also fail in a short time.

Hope this helps

 I agree: Q3 is gone. Luckily I have other Qs free to use.

Where did you find that LED inrush current is 1700 times than normal? It seems to me so much!

I have 12 lamps in parallel* 30mA each *1700 = 612A !?!?