### RS-485 communication fails

Posted:

**Mon Sep 10, 2018 2:29 pm**Trying to establish communication with Omnimeter V4 using Blink and EKM Dash on Debian Stretch, but it just keeps scrolling "Bad Meter Response" in red on the left side of the display. Here's what Hex Inspector shows me:

Send

2F 3F 30 30 30 33 35 30 30 30 33 32 32 39 30 30

21 0D 0A

[Request Data A from meter# 350003229]

Receive

02 10 24 1D 30 30 30 33 35 30 30 30 33 32 32 39

30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 30 31 31 38 34 30 30 30 30

30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 4C

30 39 39 43 30 30 30 43 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 36 30 30 32 30 30 30 30 30

30 30 34 30 30 30 30 30 30 30 30 30 30 30 30 30

30 30 30 30 31 31 32 30 30 31 38 30 39 31 31 30

33 30 35 31 30 35 36 30 30 21 0D 0A 03 4D 23

[Data A, Model: 1024, Firmware: 1D, Meter_Address: 350003229, kWh_Tot: 0.00, Reactive_Energy_Tot: 0.00, Rev_kWh_Tot: 0.00, kWh_Ln_1: 0.00, kWh_Ln_2: 0.00, kWh_Ln_3: 0.00, Rev_kWh_Ln_1: 0.00, Rev_kWh_Ln_2: 0.00, Rev_kWh_Ln_3: 0.00, Resettable_kWh_Tot: 0.00, Resettable_Rev_kWh_Tot: 0.00, RMS_Volts_Ln_1: 118.4, RMS_Volts_Ln_2: 0.0, RMS_Volts_Ln_3: 0.0, Amps_Ln_1: 0.0, Amps_Ln_2: 0.0, Amps_Ln_3: 0.0, RMS_Watts_Ln_1: 0, RMS_Watts_Ln_2: 0, RMS_Watts_Ln_3: 0, RMS_Watts_Tot: 0, Power_Factor_Ln_1: L099, Power_Factor_Ln_2: C000, Power_Factor_Ln_3: C000, Reactive_Pwr_Ln_1: 0, Reactive_Pwr_Ln_2: 0, Reactive_Pwr_Ln_3: 0, Reactive_Pwr_Tot: 0, Line_Freq: 60.02, Pulse_Cnt_1: 4, Pulse_Cnt_2: 0, Pulse_Cnt_3: 0, State_Inputs: 0, State_Watts_Dir: 1, State_Out: 1, kWh_Scale: 2, Meter_Time: 18091103051056]

Send

01 42 30 03 75

[Stop communication with meter# 350003229]

This all looks reasonable to me, but I haven't yet tried to check the checksum. Any hints what to look at next?

I have the Omnimeter V4, the Pulse, and the Blink all connected together using the green pairs of short (20 inches) lengths of Cat 5 with a third piece of Cat5 for the oscilloscope probes. I was seeing about 5 volts of 60 Hz common-mode noise on the RS-485 with the Blink disconnected, but the Blink suppresses that, and it shouldn't be a problem anyway since it's common mode (both A and B lines have the same noise except when there is data on the line.

Send

2F 3F 30 30 30 33 35 30 30 30 33 32 32 39 30 30

21 0D 0A

[Request Data A from meter# 350003229]

Receive

02 10 24 1D 30 30 30 33 35 30 30 30 33 32 32 39

30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 30 31 31 38 34 30 30 30 30

30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 4C

30 39 39 43 30 30 30 43 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 36 30 30 32 30 30 30 30 30

30 30 34 30 30 30 30 30 30 30 30 30 30 30 30 30

30 30 30 30 31 31 32 30 30 31 38 30 39 31 31 30

33 30 35 31 30 35 36 30 30 21 0D 0A 03 4D 23

[Data A, Model: 1024, Firmware: 1D, Meter_Address: 350003229, kWh_Tot: 0.00, Reactive_Energy_Tot: 0.00, Rev_kWh_Tot: 0.00, kWh_Ln_1: 0.00, kWh_Ln_2: 0.00, kWh_Ln_3: 0.00, Rev_kWh_Ln_1: 0.00, Rev_kWh_Ln_2: 0.00, Rev_kWh_Ln_3: 0.00, Resettable_kWh_Tot: 0.00, Resettable_Rev_kWh_Tot: 0.00, RMS_Volts_Ln_1: 118.4, RMS_Volts_Ln_2: 0.0, RMS_Volts_Ln_3: 0.0, Amps_Ln_1: 0.0, Amps_Ln_2: 0.0, Amps_Ln_3: 0.0, RMS_Watts_Ln_1: 0, RMS_Watts_Ln_2: 0, RMS_Watts_Ln_3: 0, RMS_Watts_Tot: 0, Power_Factor_Ln_1: L099, Power_Factor_Ln_2: C000, Power_Factor_Ln_3: C000, Reactive_Pwr_Ln_1: 0, Reactive_Pwr_Ln_2: 0, Reactive_Pwr_Ln_3: 0, Reactive_Pwr_Tot: 0, Line_Freq: 60.02, Pulse_Cnt_1: 4, Pulse_Cnt_2: 0, Pulse_Cnt_3: 0, State_Inputs: 0, State_Watts_Dir: 1, State_Out: 1, kWh_Scale: 2, Meter_Time: 18091103051056]

Send

01 42 30 03 75

[Stop communication with meter# 350003229]

This all looks reasonable to me, but I haven't yet tried to check the checksum. Any hints what to look at next?

I have the Omnimeter V4, the Pulse, and the Blink all connected together using the green pairs of short (20 inches) lengths of Cat 5 with a third piece of Cat5 for the oscilloscope probes. I was seeing about 5 volts of 60 Hz common-mode noise on the RS-485 with the Blink disconnected, but the Blink suppresses that, and it shouldn't be a problem anyway since it's common mode (both A and B lines have the same noise except when there is data on the line.