Problem with ads1x15 - readings messed up

[pakagi]

Hello,

I observe this problem when trying to read voltages using the ads1x15 module, with ADS1115 A/D connected via I2C.

It has four input channels for measuring voltage. When I use just one channel, config like this:

sensor_modules:
  - name: ads_ch0
    module: ads1x15
    type: ADS1115
    pin: 0
sensor_inputs:
  - name: voltage_0
    module: ads_ch0
    interval: 10
    type: voltage

it is working fine, I get correct readings like:

2022-02-06 13:57:41 mqtt_io.server [INFO] Read sensor 'voltage_0' value of 3.3
2022-02-06 13:57:51 mqtt_io.server [INFO] Read sensor 'voltage_0' value of 3.3

But as soon as I try to use more than one channel, it seems to randomly report either correct value or the value from the other channel. Config is like:

sensor_modules:
  - name: ads_ch0
    module: ads1x15
    type: ADS1115
    pin: 0
  - name: ads_ch1
    module: ads1x15
    type: ADS1115
    pin: 1
sensor_inputs:
  - name: voltage_0
    module: ads_ch0
    interval: 10
    type: voltage
  - name: voltage_1
    module: ads_ch1
    interval: 10
    type: voltage

and instead of reporting 3.3V on channel 0 and 0.56V on channel 1 (what is really on inputs...), it randomly mixes those:

2022-02-06 14:04:47 mqtt_io.server [INFO] Read sensor 'voltage_1' value of 0.56
2022-02-06 14:04:47 mqtt_io.server [INFO] Read sensor 'voltage_0' value of 0.56
2022-02-06 14:04:57 mqtt_io.server [INFO] Read sensor 'voltage_0' value of 0.56
2022-02-06 14:04:57 mqtt_io.server [INFO] Read sensor 'voltage_1' value of 0.56
2022-02-06 14:05:07 mqtt_io.server [INFO] Read sensor 'voltage_1' value of 3.3
2022-02-06 14:05:07 mqtt_io.server [INFO] Read sensor 'voltage_0' value of 3.3
2022-02-06 14:05:17 mqtt_io.server [INFO] Read sensor 'voltage_0' value of 0.56
2022-02-06 14:05:17 mqtt_io.server [INFO] Read sensor 'voltage_1' value of 0.56
2022-02-06 14:05:27 mqtt_io.server [INFO] Read sensor 'voltage_1' value of 3.3
2022-02-06 14:05:27 mqtt_io.server [INFO] Read sensor 'voltage_0' value of 3.3
2022-02-06 14:05:37 mqtt_io.server [INFO] Read sensor 'voltage_0' value of 0.56
2022-02-06 14:05:37 mqtt_io.server [INFO] Read sensor 'voltage_1' value of 0.56

Please I'm doing anything wrong, or is that a bug ?

[pakagi]

After more playing with it: the problem seems to be, that (as the poll interval is equal for all those 4 sensor_inputs) it tries to get the values for the sensor_modules instances mostly in parallel, and something like mixing requests and responses happens (maybe on I2C level ?) causing wrong value read. If the intervals are e.g. 5 and 7, the returned values are ok - at least seems to be the case at the moments the intervals do not meet.

So looks like fix would be: for one particular sensor, serialize the operations to read the values from sensor.

I will fill a bug issue...