Hi,
I want to log data from 4 load cells with an Artemis OpenLog. Logging starts fine, but then stops after a while.
Here is the hardware Set up: 4 mini load cells (500g, TAL 221, SEN-14728) each connected to a SparkFun Qwiic Scale NAU7802 connected via Qwiic cable to SparkFun QwiicBus EndPoint (Com-16988), connected via 1m RJ-45 cable to another SparkFun QwiicBus EndPoint, connected via Qwiic cable to SparkFun Qwiic multiplexer (TCA 9548A), connected via Qwiic cable to SparkFun OpenLog Artemis.
At the start it works fine, but at some point (after many minutes) logging stops (that is, instead of actual weight values, I get only 31.76, 0.00, 0.00, 0.00 on all consecutive lines no matter how much pressure I put on the load cells. I can provoke the same behaviour, when I briefly disconnect any of the 4 sensor cables (eg Qwiic cable from scale to endpoint or RJ-45 cable). So I deduce that the problem occurs as soon as connection between one of the sensors to the Artemis is briefly interrupted.
In the Artemis intro it also says “The Qwiic bus is pretty tolerant to “hot swapping”, but: disconnecting a sensor while it is in use will confuse the OLA software”. This is, what seems to be my problem. Having several sensor connected and running for a long time (a day) seems to make it very likely that at some point one signal from one of the scales is missed and this seems to be enough to “confuse” the Artemis software.
Is there a way how this can be avoided?
Here is an example from the terminal output:
⸮⸮⸮H⸮⸮⸮ѕ⸮⸮́OpenLog v1.7
Logging to: dataLog00376.TXT
Failed to create settings file
Failed to create sensor data file
SD card online
Datalogging offline
Serial logging offline
IMU online
Identifying Qwiic Muxes...
Identifying Qwiic Devices...
Multiplexers found. Scanning sub nets...
...
Unknown device at address (0x6E)(Mux:0x70 Port:3)
Known I2C address but device failed identification at address 0x77
Unknown device at address (0x79)(Mux:0x70 Port:3)
Autodetect complete
LoadCell-NAU7802 online at address 0x2A.0x70.2
LoadCell-NAU7802 online at address 0x2A.0x70.3
LoadCell-NAU7802 online at address 0x2A.0x70.5
LoadCell-NAU7802 online at address 0x2A.0x70.6
Multiplexer online at address 0x70
rtcDate,rtcTime,weight(no unit),weight(no unit),weight(no unit),weight(no unit),
10/14/2020,12:07:26.63,0.00,0.00,77.30,1.09,
10/14/2020,12:07:26.83,7.58,0.00,77.25,1.15,
10/14/2020,12:07:27.03,7.68,0.00,77.27,1.12,
10/14/2020,12:07:27.23,7.64,0.00,77.17,1.18,
...
10/14/2020,12:46:16.71,11.08,0.00,2.45,1.64,
10/14/2020,12:46:16.91,11.04,0.00,2.40,0.00,
10/14/2020,12:46:17.70,31.76,0.00,0.00,0.00,
10/14/2020,12:46:17.90,31.76,0.00,0.00,0.00,
10/14/2020,12:46:18.10,31.76,0.00,0.00,0.00,
10/14/2020,12:46:18.30,31.76,0.00,0.00,0.00,
Bernhard