ECOM100 blocking the bus

[Angelo]

Dear all,

I have an H4-ECOM100 module, and it appears to be causing a problem in my system. When this module is installed together with the other modules, the D4-450 CPU cannot communicate with any module on the bus. However, when I remove the H4-ECOM100 module from the bus, everything returns to normal.

Therefore, I concluded that something is wrong with the H4-ECOM100 module.

Could someone please help me?

Best regards,
Angelo

[Angelo]

Just removed the board to make some measurements with voltimeter.

What I´ve found:

 the IC (U13) which is a LJ245A, see photo below, there is a short between ping 13 (GND) to pin 3 (A1).

See that the U15 and U14 are also the same LJ245A

The LJ245A is the marking of Texas Intrument SN74LVC4245A. This CI is Octal Bus Transceiver and 3.3-V to 5-V Shifter
With 3-State Outputs.

Using ChatGPT I got a response like this:


"9. Definitive Test

The best method is to:

remove the IC,
test whether the bus communication returns,
or replace it directly.

Since you already work with PLCs and industrial buses:

if removing the IC causes the system to “come back to life” or restores communication,
then the IC is most likely internally locking up the bus.

This is extremely common."


Which seems to be the case as it cites  "lockin up the bus"


I will try to find the IC to purchase and then replace it.
 

[franji1]

It may be a bent connector pin.  405 modules have that issue since they are rotated/levered into position and the connector sometimes doesn't line up perfectly and ends up bending pin(s).

[Angelo]

I have checked. All pins are perfect aligned.

The system was running fine for the last 8 years, nobody removed the ECOM100 from the bus since then. So the bent pins hypothesis  would have 0% to be the case.


I forgot to ulpload the photo.