X-NUCLEO-PLM01A1 + STEVAL-XPLM01CPL not working

[ABasi.2]

Hello

i have a pair of X-NUCLEO-PLM01A1  plugged on two NUCLEO-G071RB that communicate in P2P mode, one is master board and one is slave board

i have adapted the example provided by ST to work on this boards:

 https://www.st.com/en/embedded-software/x-cube-plm1.html

The communications  using a 2 wire to connect the CN1 on the  X-NUCLEO-PLM01A1 is completely functional

BUT

if i try to connect the two board using two STEVAL-XPLM01CPL is not working anymore

i connect the two high voltage side on the 230VAC 50Hz same socket and the two low voltage side to the respective X-NUCLEO-PLM01A1

there is some modification to do on the example or should be work?

anyone have the same issue ?

[Didier HERROUIN]

Hello,

No, there is no HW/FW modification to apply.

What is your operating frequency ? To ensure that you communicate in Cenelec B or C band, for which the coupling filter was designed.

For the connection, you can refer to User Manual UM2188 : the DC voltage to supply the X-NUCLEO-PLM01A1 boards should be connected to CN2 connectors, and each STEVAL-XPLM01CPL should be connected to CN1 connectors (and AC connected to STEVAL-XPLM01CPL J1 connectors).
If you still face issues, let me know if you can measure PLC signals on secondary side (on CN1).

Best regards,

Didier

[ABasi.2]

Hello and thank you for your responce Mr didier

i'm using the example provided by ST arranged to match my micro, can you tell me pleas whre to find what operating frequency i'm using?

i can tell you i'm using #define USE_DL_DATA

and 

#define CUSTOM_MIB_FREQUENCY 0

#define FREQUENCY_OVERWRITE 0

#define FREQUENCY_SET 1

#define GAIN_SELECTOR 0

i didn't make any modification to the ST example

the phy_config constant is :

const uint8_t phy_config[14] = {0x01, 0xC9, 0x08, 0x01, 0x8E, 0x70, 0x0E, 0x15, 0x00, 0x00, 0x02, 0x35, 0x9B, 0x58};

and using USE_DL_DATA the modem config is:

const uint8_t modem_config[1] = {0x11};

i think my Hw setup is ok, the problem appear only if i want to use the  two STEVAL-XPLM01CPL 

idf i connect the two X-NUCLEO-PLM01A1 directly each other it work perfect

can you tell me if the ST example  https://www.st.com/en/embedded-software/x-cube-plm1.html

should work with the STEVAL-XPLM01CPL connected to a 230VAC 50Hz?

thank you

[Didier HERROUIN]

Hello,

Yes, it works with the STEVAL-XPLM01CPL connected to a 230VAC 50Hz.
Please provide a picture of your connections.

[ABasi.2]

hello

little update

 i'm now able to communicate if i connect the two STEVAL-XPLM01CPL on the same multi socket adapter

but if i try to connect one board to one socket and the other board to asnother socket in the same building (actually the two socket are very close to each other) don't work

i have some oscilloscope measure for you:

all the measure are made on the low voltage signal side 

in this image we see the communication working, the measure is made on the master board

this is when work, we see the master board send and the slave board respond

in this image we see the communication no working from master board point of view:

the signal is shorter in time

this is the communication not working from the slave board point of view

it seems to me a HW issue , like the signal is unable to flow on the real 230VAC line

here my setup, of coarse i have two of these:

any guess?

thank you

[Didier HERROUIN]

Hello, 

If you perform the test in a building, you should check that you are connected to the same phase. Indeed, most of the time in a building, the AC sockets are spread over the 3 phases and it is difficult to identify each phase (it can be split by floor, but sometimes it is split per room).
Please perform the test in a room or in a place where only 1 phase is present.

[ABasi.2]

Hi!

you are right but i'm triing in the same room in an office, just one desck after mine.. i think i have only one phase.

just to be sure this evening i try at home where i'm really sure i have only one phase for all of my home

i will update  you after the test

thank you

[ABasi.2]

Hello Didier

i have tried at home where i'm sure i have only one phase but didn't work, fro now the only way to be functioning is to plug the board in the same multi socket..

maybe 12V dc on the PLM01A1 Iisnt enough? what is the max voltage DC i can use?

thank you

[ABasi.2]

HELLO

i have another little update on the problem

the problem seems to appear only if i use an existing power  electrical system

if use an external cable (like 20 meters) it works , but if i want to use the existing electrical sistem it not work anymore..

here the setup that is working:

and here the setup NOT working:

i can't understand the difference.. i have tried the not working setup also at home where i'm sure i have only one phase...

any guess?

thank you

[Didier HERROUIN]

You are right, the 2 setups should be quite similar.

In the first case, the link is direct and short.

In the second case, you will be more exposed to the noises generated by the other devices connected to the network. Then, the impedance seen by the transmitter could be lower, PLC signal would more attenuated and current required to transmit may be higher.
What is the current capability of your PSU ?
Please probe the 12V to check if it does not collapse during the transmission.

A zoom of the PLC signal at slave side (when the communication fails) may be also interesting.