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Dec 11, 2019, 05:26 PM
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glowen's Avatar

MZ-32 and PBS-P16 HoTT Telemetry


Hi Manny,

I really need your help with something.
I recently learned of a pressure sensor made by Powerbox Systems (PBS) that is advertised to support the HoTT protocol -- the PBS-P16.
This was exciting news as I have been looking for a telemetry sensor that could be used to monitor the air pressure for pneumatic retracts.

https://powerbox-americas.com/collec...30343427981384

One was purchased but so far I have been unable to get it to work with my MZ-32.
I have been in contact with PBS via their forum (see below).

http://forum.powerbox-systems.com/fo.../6393-pbs-p16/

According to the PBS rep, the P16 works fine with the MX-20 as shown in the attached pictures.
He also indicated he did not have any experience with the MZ-32.
He also provided a picture of the data parameter definition that PBS uses for the P16 HoTT telemetry output.

I was able to download the MX-20 manual but was unable to find any detailed info regarding this telemetry parameter.

Questions for you:

1) Do you recognize the telemetry parameter displayed on the MX-20?
2) If so, which HoTT parameter is it?
3) Is that same HoTT parameter supported in the MZ-32?

Thanks in advance,
Gary
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Dec 11, 2019, 10:26 PM
Registered User
This is NOT Mannie but I might be able to provide you with some information about this. I have developed my own sensor and solution for pressure measurement about a year ago. The MZ32 monitors the pressure, provides audio warnings at certain pressure values and can activate functions i.e. deploy the gear. The sensor is interfaced to the MZ32 via the General Engine Module analog input, but that is a different subject.

The pressure value/parameter is part of Graupner’s General Air Module / General Engine Module data stream. While Graupner has added the pressure parameter (among some other new ones) to the GAM HoTT protocol a while back, it is not fully implement in all transmitters firmware for display and/or processing.

The way these 3rd party devices work is that they emulate one of the Graupner Modules i.e. GPS, GAM, EAM. In this case Powerbox uses the General Air Module address/ID as it is the only one supporting the data type. Essentially nothing wrong with that approach, except that you loose the ability to use a General Air Module at the same time (address conflict).

The current TX firmware does not yet support the full use of this telemetry parameter. So far I have found that only the MZ12-PRO can display the pressure value (see picture), none has the ability to fully process the parameter for Sensor Switch, Warnings, etc. As of now I have evaluated the MZ24-PRO, MZ12-PRO and the MZ32. I have not evaluated any of the older/tray transmitters. So for the time being you will not be able to get it on the MZ32.

Hope this helps.
Last edited by yrag; Dec 11, 2019 at 11:02 PM.
Dec 12, 2019, 10:45 AM
Registered User
glowen's Avatar
Quote:
Originally Posted by yrag
This is NOT Mannie but I might be able to provide you with some information about this. I have developed my own sensor and solution for pressure measurement about a year ago. The MZ32 monitors the pressure, provides audio warnings at certain pressure values and can activate functions i.e. deploy the gear. The sensor is interfaced to the MZ32 via the General Engine Module analog input, but that is a different subject.

The pressure value/parameter is part of Graupner’s General Air Module / General Engine Module data stream. While Graupner has added the pressure parameter (among some other new ones) to the GAM HoTT protocol a while back, it is not fully implement in all transmitters firmware for display and/or processing.

The way these 3rd party devices work is that they emulate one of the Graupner Modules i.e. GPS, GAM, EAM. In this case Powerbox uses the General Air Module address/ID as it is the only one supporting the data type. Essentially nothing wrong with that approach, except that you loose the ability to use a General Air Module at the same time (address conflict).

The current TX firmware does not yet support the full use of this telemetry parameter. So far I have found that only the MZ12-PRO can display the pressure value (see picture), none has the ability to fully process the parameter for Sensor Switch, Warnings, etc. As of now I have evaluated the MZ24-PRO, MZ12-PRO and the MZ32. I have not evaluated any of the older/tray transmitters. So for the time being you will not be able to get it on the MZ32.

Hope this helps.
Definitely not what I wanted to hear but many thanks for the info.
At least I know where things stand now.

Was wondering if we could take this discussion offline via PM as I am very interested to talk to you about your workaround solution?
I was planning on doing the same thing until I had recently learned about the PBS-P16 sensor.
Dec 12, 2019, 04:17 PM
Registered User
glowen's Avatar
Mannie,

Do you know of any plans to add the processing / display of this pressure telemetry parameter as part of a future MZ-32 software update? If not, could you please put it on the "list"? I don't think I'm the only 32 user out there that would be interested in this.

Thanks,
Gary
Dec 12, 2019, 07:06 PM
Registered User
Quote:
Originally Posted by glowen
Definitely not what I wanted to hear but many thanks for the info.
At least I know where things stand now.

Was wondering if we could take this discussion offline via PM as I am very interested to talk to you about your workaround solution?
I was planning on doing the same thing until I had recently learned about the PBS-P16 sensor.
Sent you a PM.
Basically I developed a circuit around a precision pressure sensor ( see picture) which provides an analog voltage. The pressure signal is connected to one of the Voltage ports of GeneralEngineModule. The rest I am handling with the MZ32 with custom voice files and logic programming - the MZ32 has great flexibility for that!
That way I also have access to the other features of the GeneralEngineModule i.e. Engine Temperature, Realtime Engine RPM, Ignition Battery ...... The GeneralEngineModule is a rather nice and flexible module.
Dec 12, 2019, 10:35 PM
Graupner USA's Avatar
It is on the list together with some other telemetry specific issues that need to be fixed.

I would advice you to work with Gary as his device is something that we should consider producing.
Dec 12, 2019, 10:46 PM
Registered User
glowen's Avatar
Quote:
Originally Posted by yrag
Sent you a PM.
Basically I developed a circuit around a precision pressure sensor ( see picture) which provides an analog voltage. The pressure signal is connected to one of the Voltage ports of GeneralEngineModule. The rest I am handling with the MZ32 with custom voice files and logic programming - the MZ32 has great flexibility for that!
That way I also have access to the other features of the GeneralEngineModule i.e. Engine Temperature, Realtime Engine RPM, Ignition Battery ...... The GeneralEngineModule is a rather nice and flexible module.
Holy smokes man, that is awesome!!! It even has SMT devices on it. Wow, when you build something you do a very professional job.
This sounds similar to the design approach I had been contemplating but I hadn't gotten past just the thinking stage.
I wanted to come up with a circuit which would have a scaled output of like 10VDC and fed to one of the voltage inputs on the GEM or GAM when the sensed pressure was 100 PSI etc. (for all of the same reasons you state above)

Anyway, I sent you a couple of PM's yesterday but apparently you haven't seen them yet?
(and I haven't received yours yet either)

Well now for the obvious question...
Could a guy like me purchase some of these beauties???
Dec 12, 2019, 11:07 PM
Registered User
glowen's Avatar
Quote:
Originally Posted by Graupner USA
It is on the list together with some other telemetry specific issues that need to be fixed.

I would advice you to work with Gary as his device is something that we should consider producing.
Thanks Mannie.

I sure hope that telemetry parameter can be remedied sooner rather than later in the MZ radios.
The PBS pressure sensor is a very high quality device. It would be awesome to be able to use it.
For me, and probably others, it's the only thing missing for the desired telemetry data on a warbird.
(ex: rpm, voltage, temperature, fuel and last but not least, air pressure)
Last edited by glowen; Dec 12, 2019 at 11:11 PM. Reason: deleted N/A text
Dec 19, 2019, 05:50 PM
Registered User
Mz32 is stupid

Free one in the trash if you know where I live and can beat the trash man in the morning., dont bother with a PM because I'll be at work and wont have internet service
Last edited by Joshadam; Dec 19, 2019 at 08:37 PM.
Dec 19, 2019, 07:10 PM
Registered User
Quote:
Originally Posted by yrag
Sent you a PM.
Basically I developed a circuit around a precision pressure sensor ( see picture) which provides an analog voltage. The pressure signal is connected to one of the Voltage ports of GeneralEngineModule. The rest I am handling with the MZ32 with custom voice files and logic programming - the MZ32 has great flexibility for that!
That way I also have access to the other features of the GeneralEngineModule i.e. Engine Temperature, Realtime Engine RPM, Ignition Battery ...... The GeneralEngineModule is a rather nice and flexible module.
The MZ32 Under Pressure (I couldn't resist )
Attached is a compressed video of the MZ32 announcing pressure levels as previously described.
Dec 20, 2019, 11:32 AM
Registered User
glowen's Avatar
Quote:
Originally Posted by Joshadam
Mz32 is stupid

Free one in the trash if you know where I live and can beat the trash man in the morning., dont bother with a PM because I'll be at work and wont have internet service
Are you sure this just isn't a case of ESO?
Dec 25, 2019, 05:22 PM
Registered User
SteveJF's Avatar

Battery Issues


My MZ32 wouldn’t boot. After about 3 flights (1hr of operation) I went to turn on and it was dead. The last flight didn’t produce a low voltage warning. I connected the charger and got 5 greens followed by 1 green. (Where is this documented?) The open circuit voltage is 3.8V which seems low for only 1 hr. The internal resistance is 900mohm and the charge current is only 200ma at 4.2v. Could it be about to fail open? Is this a known issue? The battery has only about 25 cycles and has never been abused.

Steve
Dec 26, 2019, 07:39 AM
'n boer maak 'n plan
yufasa's Avatar
Thread OP
These radio batteries have some sort of protection circuit built in and that could have failed but I have not heard of that happening on the Graupner ones yet. Normally these fail if you use an external charger to charge at high currents not in normal use.
Do you have another power source(battery) you can test the radio with?

Either way I suggest you get hold of Graupner (holidays I know) and have them help you get this going again...
Dec 26, 2019, 10:41 PM
Registered User
SteveJF's Avatar

Battery Issues Continued


No answer at Graupner today. I disassembled the battery and found this charge protection PCB. The cells themselves appeared in good shape, so I assumed that it had failed. I removed the FETs and soldered the black leads directly to the negative battery terminal. I put the battery on my smart charger set for 2A and it’s been charging for several hours now. The charge current started at 0.6A but declined to 200ma at 4.20v after about 1hr. The open circuit internal resistance is still 900mohm even without the PCB which is disturbing. After it finishes charging I’ll replace it in the Tx and see how long it stays up under load.

I did find the battery listed for $90 on several websites but all out of stock. Chief said they expect supply problems until production is relocated to Korea.
Dec 27, 2019, 06:54 AM
'n boer maak 'n plan
yufasa's Avatar
Thread OP
The IR is a bit of a concern for sure but the fact that the charge rate dropped at 4.2 is good...
I would think that it would work unless something went terribly wrong.


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