Sonde drawing too much?

[cmchrist]

I am working on integrating an EXO2 sonde into the Smart Mooring system using a DCP Signal Output Adapter (to spit out RS-232). Here are the specifications for the instrument using this adapter…

• Supply Voltage: 9-16 VDC
• Current Draw Adapter: ~20 mA typical (@12VDC)
• Current Draw Sonde: ~sleep 0.25mA reading and 100 mA during operation
• Max Net Current Draw for Systems: ~120 mA (@ 12VDC)

I wired the sonde/adapter to the dev kit and the V was fluctuating between 12 and 11 V at a 1 second interval and the sonde was not taking readings. I then removed the adapter’s power and ground wires from the dev kit and wired them to an external battery and everything was working fine. I also tested the dev kit’s V-OUT and ground without anything wired in and the V was as expected and stable.

Does that mean the sonde is drawing too much for the dev kit and I have to rely on external battery power for the sonde?

[zack_j]

Hey there, it might be helpful to see a wiring diagram of your total system so we can get a full view of what’s going on. A photo might suffice as well if we can easily see the pin outs…

Thanks,
Z

[cmchrist]

Is this helpful?

[zack_j]

Cobi, I’m sorry I lost track of this post…

Something that might be helpful is to use the power monitor referred to in the RS232 integration guide under the section “Physically integrate the sensor”

There’s a few key elements of this tool that we’re still working hard to document more thoroughly:

hope this helps!

---

Power monitoring

The Bristlemouth Development has two different INA232 power monitor ICs that monitor voltage and bi-directional current.

0x41 / D65 - measures power flowing into Port 2 of the Mote. This power goes to the Mote, the Bristlemouth Development Board, and through the Mote to any downstream consumers.

0x43 / D67 - measures power delivered to 5V and Vout (9-19V) rails on the Bristlefin (Dev Board). Note - measured at the 24V level.

These are controlled in the firmware by **sensorsPollIntervalMs**More information can be found in Guide 5:

Bristlemouth Dev Kit Guide 5: Developing a Simple Application

Some notes about the current implementation of this:

• The accuracy is about +/- 0.5mA.
• The Bristlemouth Mote orientation matters.
• The default hello world app will consume about 150mW.
• Currently there is no simple way to distinguish the Bristlemouth ports on the Development Board.

Here’s an example of the power monitor:

Powering from Port 1 - no power is measured:

power | tick: 26209, rtc: 0, addr: 65, voltage: 23.929600, current: -0.000250

Powering from Port 2 - ~160mW is measured:

power | tick: 22209, rtc: 0, addr: 65, voltage: 23.929600, current: 0.006750

[zack_j]

Adding this here as well in case it’s helpful.

If we want to test whether or not the load is causing the issue we can put a power resistor in place to simulate a load.

@evan recommended a 50 ohm power resistor with a 10W rating, like: HS10 50R J Ohmite | Resistors | DigiKey.

Using the 12V Vout output, you should get 240mA / ~3W of power dissipation in the resistor which is 2x the expected power of the Sonde and should be no issue for the dev board when powering off of wall wart or Spotter. We’d recommend trying the wall-wart first and then the Spotter (with full batteries).

Please note that the resistor will get hot to the touch. Don’t put it on or near anything flammable.

[cmchrist]

I just did some testing with the 50 ohm power resistor and everything checked out. I was measuring 240 mA using the 12V Vout output. I talked to YSI and they are also stumped as to why there is a power issue.

Here is a snippet of what the board was reading before and after connecting the sonde (removed some of the line for simplicity)…

---

No sonde connected:
power | addr: 67, voltage: 24.059200, current: 0.000000
power | addr: 65, voltage: 24.059200, current: 0.006250

power | addr: 67, voltage: 24.059200, current: 0.000000
power | addr: 65, voltage: 24.059200, current: 0.006500

---

Sonde Connected:
power | addr: 67, voltage: 24.054399, current: 0.008750
power | addr: 65, voltage: 24.056000, current: 0.015000

power | addr: 67, voltage: 24.054399, current: 0.008750
power | addr: 65, voltage: 24.036800, current: 0.012500

power | addr: 67, voltage: 24.054399, current: 0.008750
power | addr: 65, voltage: 24.056000, current: 0.014000

power | addr: 67, voltage: 24.035200, current: 0.003250
power | addr: 65, voltage: 24.056000, current: 0.015250

power | addr: 67, voltage: 24.038401, current: 0.003750
power | addr: 65, voltage: 24.046400, current: 0.013750

power | addr: 67, voltage: 24.035200, current: 0.002250
power | addr: 65, voltage: 24.036800, current: 0.012500

power | addr: 67, voltage: 23.896000, current: 0.005750
power | addr: 65, voltage: 24.036800, current: 0.010250

power |addr: 67, voltage: 24.054399, current: 0.008750
power | addr: 65, voltage: 24.056000, current: 0.016500

---

No sonde connected:
power | addr: 67, voltage: 24.059200, current: 0.000000
power | addr: 65, voltage: 24.060801, current: 0.006250

power |addr: 67, voltage: 24.059200, current: 0.000000
power |addr: 65, voltage: 24.060801, current: 0.006500

[zack_j]

Interesting. With no sonde connected this is with the 50ohm resistor connected? Did you notice the power cycling with the resistor as well as the sonde?

[zack_j]

Let’s do this:

Set up (A): connect the 50 Ohm resistor to the Vout and ground. Turn on the development kit, screen in, and paste the output of the screen session here (including the power monitor data). Maybe about ~1 minute.

Set up (B): disconnect the 50 Ohm resistor. Now connect the sonde and the RS232 board as shown in the diagram above. Power up and screen in. Include the entire screen session as well for that. Maybe about ~1 minute of data.

Set up (C): disconnect the data lines to the sonde but keep it connected electrically. Let’s power up and screen in for a minute and paste the output here.

Specifically we want to see what the power draw is with the 50 ohm resistor so we can find out if there are any power issues with the board or cycling of the code without the Sonde attached.

We’ll schedule some office hours (zoom) asap to dig in.

Thanks
Z

[cmchrist]

Set up (A): connect the 50 Ohm resistor to the Vout and ground. Turn on the development kit, screen in, and paste the output of the screen session here (including the power monitor data). Maybe about ~1 minute.

pressure | tick: 10385, rtc: 0, temp: 22.760000, pressure: 1017.440002
power | tick: 10387, rtc: 0, addr: 67, voltage: 23.921600, current: 0.133250
power | tick: 10389, rtc: 0, addr: 65, voltage: 23.940800, current: 0.139000
hum_temp | tick: 20364, rtc: 0, hum: 68.615479, temp: 23.163437
pressure | tick: 20385, rtc: 0, temp: 22.780001, pressure: 1017.419983
power | tick: 20387, rtc: 0, addr: 67, voltage: 23.921600, current: 0.133000
power | tick: 20389, rtc: 0, addr: 65, voltage: 23.940800, current: 0.139000
hum_temp | tick: 30364, rtc: 0, hum: 68.768066, temp: 23.174162
pressure | tick: 30385, rtc: 0, temp: 22.820000, pressure: 1017.559998
power | tick: 30387, rtc: 0, addr: 67, voltage: 23.921600, current: 0.133000
power | tick: 30389, rtc: 0, addr: 65, voltage: 23.940800, current: 0.138750
hum_temp | tick: 40364, rtc: 0, hum: 68.676514, temp: 23.174162
pressure | tick: 40385, rtc: 0, temp: 22.850000, pressure: 1017.619995
power | tick: 40387, rtc: 0, addr: 67, voltage: 23.921600, current: 0.132750
power | tick: 40389, rtc: 0, addr: 65, voltage: 23.940800, current: 0.138750
hum_temp | tick: 50364, rtc: 0, hum: 68.493408, temp: 23.206337
pressure | tick: 50385, rtc: 0, temp: 22.889999, pressure: 1017.419983
power | tick: 50387, rtc: 0, addr: 67, voltage: 23.923201, current: 0.132750
power | tick: 50389, rtc: 0, addr: 65, voltage: 23.942400, current: 0.138750
hum_temp | tick: 60364, rtc: 0, hum: 68.584961, temp: 23.227789
pressure | tick: 60385, rtc: 0, temp: 22.950001, pressure: 1017.609985
power | tick: 60387, rtc: 0, addr: 67, voltage: 23.923201, current: 0.132750
power | tick: 60389, rtc: 0, addr: 65, voltage: 23.942400, current: 0.138500
hum_temp | tick: 70364, rtc: 0, hum: 68.310303, temp: 23.270689
pressure | tick: 70385, rtc: 0, temp: 23.010000, pressure: 1017.630005
power | tick: 70387, rtc: 0, addr: 67, voltage: 23.923201, current: 0.132750
power | tick: 70389, rtc: 0, addr: 65, voltage: 23.942400, current: 0.138500
hum_temp | tick: 80364, rtc: 0, hum: 68.066162, temp: 23.313589
pressure | tick: 80385, rtc: 0, temp: 23.070000, pressure: 1017.539978
power | tick: 80387, rtc: 0, addr: 67, voltage: 23.923201, current: 0.132500
power | tick: 80389, rtc: 0, addr: 65, voltage: 23.942400, current: 0.138500
hum_temp | tick: 90364, rtc: 0, hum: 68.035645, temp: 23.345764
pressure | tick: 90385, rtc: 0, temp: 23.110001, pressure: 1017.369995
power | tick: 90387, rtc: 0, addr: 67, voltage: 23.923201, current: 0.132500
power | tick: 90389, rtc: 0, addr: 65, voltage: 23.942400, current: 0.138500
hum_temp | tick: 100364, rtc: 0, hum: 67.822021, temp: 23.388664
pressure | tick: 100385, rtc: 0, temp: 23.180000, pressure: 1017.460022
power | tick: 100387, rtc: 0, addr: 67, voltage: 23.924801, current: 0.132500
power | tick: 100389, rtc: 0, addr: 65, voltage: 23.942400, current: 0.138500

Set up (B): disconnect the 50 Ohm resistor. Now connect the sonde and the RS232 board as shown in the diagram above using power from board. Power up and screen in. Include the entire screen session as well for that. Maybe about ~1 minute of data.

pressure | tick: 10385, rtc: 0, temp: 22.430000, pressure: 1017.700012
power | tick: 10387, rtc: 0, addr: 67, voltage: 24.062401, current: 0.009000
power | tick: 10389, rtc: 0, addr: 65, voltage: 24.063999, current: 0.017000
hum_temp | tick: 20364, rtc: 0, hum: 60.741943, temp: 22.691534
pressure | tick: 20385, rtc: 0, temp: 22.430000, pressure: 1018.030029
power | tick: 20387, rtc: 0, addr: 67, voltage: 24.067200, current: 0.009000
power | tick: 20389, rtc: 0, addr: 65, voltage: 24.065599, current: 0.018500
hum_temp | tick: 30364, rtc: 0, hum: 61.260742, temp: 22.680809
pressure | tick: 30385, rtc: 0, temp: 22.459999, pressure: 1018.049988
power | tick: 30387, rtc: 0, addr: 67, voltage: 24.057600, current: 0.009250
power | tick: 30389, rtc: 0, addr: 65, voltage: 24.057600, current: 0.016500
hum_temp | tick: 40364, rtc: 0, hum: 61.352295, temp: 22.702259
pressure | tick: 40385, rtc: 0, temp: 22.469999, pressure: 1017.739990
power | tick: 40387, rtc: 0, addr: 67, voltage: 24.056000, current: 0.009500
power | tick: 40389, rtc: 0, addr: 65, voltage: 24.057600, current: 0.016750
hum_temp | tick: 50364, rtc: 0, hum: 61.230225, temp: 22.766609
pressure | tick: 50385, rtc: 0, temp: 22.490000, pressure: 1017.669983
power | tick: 50387, rtc: 0, addr: 67, voltage: 24.028799, current: 0.009500
power | tick: 50389, rtc: 0, addr: 65, voltage: 24.033600, current: 0.012250
hum_temp | tick: 60364, rtc: 0, hum: 61.474365, temp: 22.755884
pressure | tick: 60385, rtc: 0, temp: 22.490000, pressure: 1017.630005
power | tick: 60387, rtc: 0, addr: 67, voltage: 24.035200, current: 0.009250
power | tick: 60389, rtc: 0, addr: 65, voltage: 24.035200, current: 0.015500
hum_temp | tick: 70364, rtc: 0, hum: 61.535400, temp: 22.777334
pressure | tick: 70385, rtc: 0, temp: 22.500000, pressure: 1017.700012
power | tick: 70387, rtc: 0, addr: 67, voltage: 24.028799, current: 0.008750
power | tick: 70389, rtc: 0, addr: 65, voltage: 24.030399, current: 0.014250
hum_temp | tick: 80364, rtc: 0, hum: 62.084717, temp: 22.809509
pressure | tick: 80385, rtc: 0, temp: 22.530001, pressure: 1017.770020
power | tick: 80387, rtc: 0, addr: 67, voltage: 24.035200, current: 0.009250
power | tick: 80389, rtc: 0, addr: 65, voltage: 24.033600, current: 0.014000
hum_temp | tick: 90364, rtc: 0, hum: 61.932129, temp: 22.863134
pressure | tick: 90385, rtc: 0, temp: 22.570000, pressure: 1017.789978
power | tick: 90387, rtc: 0, addr: 67, voltage: 23.899200, current: 0.009500
power | tick: 90389, rtc: 0, addr: 65, voltage: 24.065599, current: 0.016750
hum_temp | tick: 100364, rtc: 0, hum: 61.993164, temp: 22.863134
pressure | tick: 100385, rtc: 0, temp: 22.580000, pressure: 1017.640015
power | tick: 100387, rtc: 0, addr: 67, voltage: 23.876801, current: 0.009250
power | tick: 100389, rtc: 0, addr: 65, voltage: 24.060801, current: 0.014500
hum_temp | tick: 110364, rtc: 0, hum: 61.749023, temp: 22.927485
pressure | tick: 110385, rtc: 0, temp: 22.600000, pressure: 1017.770020
power | tick: 110387, rtc: 0, addr: 67, voltage: 23.873600, current: 0.009000
power | tick: 110389, rtc: 0, addr: 65, voltage: 24.027201, current: 0.014500

Set up (C): disconnect the data lines to the sonde but keep it connected electrically. Let’s power up and screen in for a minute and paste the output here.

pressure | tick: 10385, rtc: 0, temp: 22.700001, pressure: 1017.969971
power | tick: 10387, rtc: 0, addr: 67, voltage: 24.063999, current: 0.008000
power | tick: 10389, rtc: 0, addr: 65, voltage: 24.065599, current: 0.015000
hum_temp | tick: 20364, rtc: 0, hum: 62.359375, temp: 22.981112
pressure | tick: 20385, rtc: 0, temp: 22.690001, pressure: 1017.929993
power | tick: 20387, rtc: 0, addr: 67, voltage: 24.068800, current: 0.007750
power | tick: 20389, rtc: 0, addr: 65, voltage: 24.065599, current: 0.016250
hum_temp | tick: 30364, rtc: 0, hum: 61.932129, temp: 22.991837
pressure | tick: 30385, rtc: 0, temp: 22.700001, pressure: 1017.940002
power | tick: 30387, rtc: 0, addr: 67, voltage: 24.059200, current: 0.007500
power | tick: 30389, rtc: 0, addr: 65, voltage: 24.060801, current: 0.013500
hum_temp | tick: 40364, rtc: 0, hum: 61.718506, temp: 22.991837
pressure | tick: 40385, rtc: 0, temp: 22.690001, pressure: 1017.869995
power | tick: 40387, rtc: 0, addr: 67, voltage: 24.057600, current: 0.007250
power | tick: 40389, rtc: 0, addr: 65, voltage: 24.057600, current: 0.015250
hum_temp | tick: 50364, rtc: 0, hum: 61.382812, temp: 23.002562
pressure | tick: 50385, rtc: 0, temp: 22.700001, pressure: 1017.809998
power | tick: 50387, rtc: 0, addr: 67, voltage: 24.051201, current: 0.007000
power | tick: 50389, rtc: 0, addr: 65, voltage: 24.040001, current: 0.010500
hum_temp | tick: 60364, rtc: 0, hum: 61.657471, temp: 23.034737
pressure | tick: 60385, rtc: 0, temp: 22.709999, pressure: 1017.940002
power | tick: 60387, rtc: 0, addr: 67, voltage: 24.041599, current: 0.008000
power | tick: 60389, rtc: 0, addr: 65, voltage: 24.043200, current: 0.012750
hum_temp | tick: 70364, rtc: 0, hum: 61.657471, temp: 23.024012
pressure | tick: 70385, rtc: 0, temp: 22.730000, pressure: 1018.039978
power | tick: 70387, rtc: 0, addr: 67, voltage: 24.048000, current: 0.006500
power | tick: 70389, rtc: 0, addr: 65, voltage: 24.044800, current: 0.012750
hum_temp | tick: 80364, rtc: 0, hum: 61.199707, temp: 23.056187
pressure | tick: 80385, rtc: 0, temp: 22.750000, pressure: 1017.989990
power | tick: 80387, rtc: 0, addr: 67, voltage: 24.038401, current: 0.006000
power | tick: 80389, rtc: 0, addr: 65, voltage: 24.041599, current: 0.011250

Set up (D): disconnect the 50 Ohm resistor. Now connect the sonde and the RS232 board as shown in the diagram above using power from external battery. Power up and screen in. Include the entire screen session as well for that. Maybe about ~1 minute of data. I doubt this is useful, but including it anyways.

[payload-bytes] | tick: 4125, rtc: 0, bytes:32 31 2E 34 34 34 20 30 2E 38 31 38 20 30 2E 30 30 20 37 2E 38 32 20 0D 
[exo] | tick: 4145, rtc: 0, line: 
# 21.444 0.818 0.00 7.82 
count: 3/310

[removed payload info moving forward]

hum_temp | tick: 10363, rtc: 0, hum: 62.145752, temp: 23.088362
pressure | tick: 10384, rtc: 0, temp: 22.790001, pressure: 1017.979980
power | tick: 10386, rtc: 0, addr: 67, voltage: 24.070400, current: 0.000000
power | tick: 10388, rtc: 0, addr: 65, voltage: 24.070400, current: 0.007000
hum_temp | tick: 20363, rtc: 0, hum: 62.420410, temp: 23.045462
pressure | tick: 20384, rtc: 0, temp: 22.780001, pressure: 1017.880005
power | tick: 20386, rtc: 0, addr: 67, voltage: 24.075199, current: 0.000000
power | tick: 20388, rtc: 0, addr: 65, voltage: 24.075199, current: 0.007000
hum_temp | tick: 30363, rtc: 0, hum: 62.542480, temp: 23.109812
pressure | tick: 30384, rtc: 0, temp: 22.770000, pressure: 1017.849976
power | tick: 30386, rtc: 0, addr: 67, voltage: 24.065599, current: 0.000000
power | tick: 30388, rtc: 0, addr: 65, voltage: 24.065599, current: 0.007000
hum_temp | tick: 40363, rtc: 0, hum: 62.634033, temp: 23.099087
pressure | tick: 40384, rtc: 0, temp: 22.790001, pressure: 1017.890015
power | tick: 40386, rtc: 0, addr: 67, voltage: 24.062401, current: 0.000000
power | tick: 40388, rtc: 0, addr: 65, voltage: 24.060801, current: 0.007000
hum_temp | tick: 50363, rtc: 0, hum: 62.115234, temp: 23.109812
pressure | tick: 50384, rtc: 0, temp: 22.780001, pressure: 1017.960022
power | tick: 50386, rtc: 0, addr: 67, voltage: 24.068800, current: 0.000000
power | tick: 50388, rtc: 0, addr: 65, voltage: 24.068800, current: 0.007000
hum_temp | tick: 60363, rtc: 0, hum: 61.871094, temp: 23.163437
pressure | tick: 60384, rtc: 0, temp: 22.799999, pressure: 1018.020020
power | tick: 60386, rtc: 0, addr: 67, voltage: 24.072001, current: 0.000000
power | tick: 60388, rtc: 0, addr: 65, voltage: 24.072001, current: 0.007000
hum_temp | tick: 70363, rtc: 0, hum: 61.810059, temp: 23.152712
pressure | tick: 70384, rtc: 0, temp: 22.809999, pressure: 1017.760010
power | tick: 70386, rtc: 0, addr: 67, voltage: 24.060801, current: 0.000000
power | tick: 70388, rtc: 0, addr: 65, voltage: 24.067200, current: 0.007000
hum_temp | tick: 80363, rtc: 0, hum: 61.993164, temp: 23.141987
pressure | tick: 80384, rtc: 0, temp: 22.840000, pressure: 1017.909973
power | tick: 80386, rtc: 0, addr: 67, voltage: 24.063999, current: 0.000000
power | tick: 80388, rtc: 0, addr: 65, voltage: 24.062401, current: 0.007000
hum_temp | tick: 90363, rtc: 0, hum: 61.749023, temp: 23.206337
pressure | tick: 90384, rtc: 0, temp: 22.850000, pressure: 1017.950012
power | tick: 90386, rtc: 0, addr: 67, voltage: 24.076799, current: 0.000000
power | tick: 90388, rtc: 0, addr: 65, voltage: 24.076799, current: 0.007000

[evan]

Hi @cmchrist - just confirming that in all of the above setups the Sonde was not reporting data as expected, right?

I have one more idea/suggestion to test out ahead of a Zoom session - try adding a large electrolytic capacitor to the Vout output from the Bristlemouth Development Board.

Something like this could do the trick: https://www.digikey.com/en/products/detail/chemi-con/EKYC250ELL512ML25S/10486610
(pay attention to the polarity - there’s a + and - lead on the capacitor, and if you hook it up backwards they can explode)

• Given the test with the 50 ohm power resistor, if it is a power issue it seems very likely to be something like a turn-on spike temporarily exceeding the maximum 10W power output, leading to a brownout and reboot cycle.
• It’s plausible this is not a power issue - and something to do with turn-on sequencing being different when powering from battery or Dev Board, and that somehow resulting in a crash/data transceiver issue in the EXO Signal Output Adapter.

[cmchrist]

@evan

• It’s plausible this is not a power issue - and something to do with turn-on sequencing being different when powering from battery or Dev Board, and that somehow resulting in a crash/data transceiver issue in the EXO Signal Output Adapter.

I think this is exactly what is going on! I added fresh D-Cell batteries to the sonde and wired the power to the board and it was working as intended. If I take out the sonde’s batteries, then it must be drawing too much and the board and/or DCP adapter freaks out. I assume the d-cell batteries will take that startup load and then the sonde will be powered from the spotter moving forward.

I have not explored this yet, but I need to test what would happen during a long-term deployment in terms of power cycling. I know the spotter will lose connection with the sonde after the initial 2 minute start-up period, but that can be resolved by reconnecting after initialization period and before the deployment. I just have to monitor what happens during longer periods of time and during the sonde’s sleep mode. I will consult my colleagues the are more sonde savvy than me.

[zack_j]

Awesome that we got to the bottom of it @cmchrist. Let us know how the deployment goes!