10x PZEM-004T

ESPHome
1

Hi
I have 10 pieces PZEM-004T as energy monitor.
Sometimes 2-3 PZEMs fail. Restart usually helps.
In the log file this yellow message:
'Modbus CRC check failed! 4C65!=1404
Does anyone know the problem?

1 Like
2

Does anyone know your wiring/yaml?

3 
uart:
  id: uart1
  tx_pin: D2
  rx_pin: D1
  baud_rate: 9600
#  debug:

modbus:
  - id: mod_bus_pzem1
    send_wait_time: 250ms
    uart_id: uart1

sensor:

  - platform: pzemac
    id: Strom_Gesamt
    current:
      name: "Strom Gesamt"
    voltage:
      name: "Spannung Gesamt"
    energy:
      name: "Energie Gesamt"
    power:
      name: "Leistung Gesamt"
    frequency:
      name: "Frequenz Gesamt"
    power_factor:
      name: "Power Factor Gesamt"
    update_interval: 10s
    address: 1
    modbus_id: mod_bus_pzem1

  - platform: pzemac
    id: Strom_Aussen
    current:
      name: "Strom Aussen"
#    voltage:
#      name: "Spannung Aussen"
    energy:
      name: "Energie Aussen"
    power:
      name: "Leistung Aussen"
#    frequency:
#      name: "Frequenz Aussen"
#    power_factor:
#      name: "Power Factor Aussen"
    update_interval: 10s
    address: 2
    modbus_id: mod_bus_pzem1

etc.
PIN D2 is on an OptoCoupler PC 817 to RX from PZEM.
PIN D1 is on TX from PZEM.
All PZEM parallel.

4

No diodes on the TX’s from each pzem in your setup?

image

5

Sorry. Yes. Every PZEM have diode to TX. But no resistor to 5V :thinking:
My Optocoupler are 2 pcs parallel (one over other)
Energie

20220825_114540
20220825_1145401920Ă—864 166 KB

6

Maybe you could try to add one and see if it helps?

I wonder if they always the same ones or always “random” ones?

7

I also see you have no stop_bits (default is 1) in your uart defined. Some users claim setting it to 2 helps with the CRC check failed

8

Stop_bits: 2 → only CRC error and no data!

“…more then 4…”
that problem is no data. my problem is sometime no data and sometime any CRC-Error.

I thing i should use a 1.5 Amps PNP Transistor S8550 instead optocoupler… :man_shrugging:

Looks like my first try. 1 to 4 no problem. Direct connected.
Then 5 to … = no Data.
More then 4 with one optocoupler many CRC-Error´s.
Now two optocoupler parallel sometime CRC-error´s

9

So 4 pzem always work stable? And as soon you have more you always experiencing some sort of problems - right?

I was wondering anyways that you have 10 pzem connected to one esp82xx, I had in mind there was kind of a hard limit… but by the looks of it there isn’t - beside some unstable experiences :expressionless:

Another thing which might be worth trying is to use more than one uart bus. For example hook 4 pzem’s up to one uart bus and another 4 to another bus and another :bus: for the rest?

10

I have try 4 pcs testet for 10min. without problems.
Limit? I dont know. I have used adress 1 to 11.
Why should i use 2 uart and modbusses?

Strom
Strom302Ă—1230 39.9 KB

11

Just to see if you can avoid the problems you have… like a work’a’round (having more than 4 pzem connected to a esp but still have it stable and not throwing CRC failures and stop sending data)

12

I understand. I think the problem ist not software. I think the problem is power consumption from optocoupler in the PZEM´s oder Timing problem.
a little more timeout from adress to adress maybe…

1 Like
13

Hi
Were you able to solve your problem?
If the answer is yes, how?

14

My last Version is 2 optocoupler on top of each other for RX Optocoupler.
The Optocoupler goes to 5V and R8 from PZEM i have 500 Ohm.
Look here:
HOWTO control PZEM-004t · arendst/Tasmota · Discussion #10567 (github.com)
BTW: Sometime are 2 or 3 not available. Then i must restart ESP. Sometime 2 or 3 times.