How fast the system should react?

Discussion about this major DATV Project. See also https://wiki.batc.org.uk/The_Portsdown_Transmitter
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DG8KD
Posts: 48
Joined: Fri Nov 14, 2014 9:02 pm

How fast the system should react?

Post by DG8KD » Fri Mar 03, 2017 1:17 pm

Hi,
yesterday I received my touchscreen display and I set up my SD card.
I got it working after 2 attempts but I am not quite sure why my system is really slow.
Booting is approx. 2 minutes before the BATC logo or the touch screen menu apprears. (depending on used setting)
It took a while (approx. 30 seconds) after pressing the TX button before the screen changes to the testcard. The LED shows immediate reaction.
At least the same time to stop TX and go back to the main menu.
Is this a normal behavior or how can I speed up the reaction?
vy 73 de
Rainer

G8GKQ
Site Admin
Posts: 1819
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Re: How fast the system should react?

Post by G8GKQ » Fri Mar 03, 2017 2:56 pm

Hi Rainer

No - the system should be much faster than that.

Boot-up is normally about 30 seconds, and transmit switching less than 5 seconds. Boot-up can take longer if you do not have a network connected, but that does not sound like your problem. Even slow SD Cards don't make that much difference.

Please check: RPi 3, genuine WaveShare 3.5 inch Model A touchscreen, only power and network connected to RPi, power supply 5.0 volts + at the RPi on full load?

Dave, G8GKQ

DG8KD
Posts: 48
Joined: Fri Nov 14, 2014 9:02 pm

Re: How fast the system should react?

Post by DG8KD » Fri Mar 03, 2017 4:30 pm

Hi Dave,

Thanks for the quick reply:

checked:
RPi 3: YES
genuine WaveShare 3.5 inch Model A touchscreen: No genuine one but no driver needed, no mods needed, setting to waveshare and directly working
only power and network connected to RPi: YES
power supply 5.0 volts + at the RPi on full load? : YES, 2A @ 5V , checked on PI, also no "flash" symbol on touch screen , occurs when physically reduce input voltage

Thanks
Rainer

G8GKQ
Site Admin
Posts: 1819
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Re: How fast the system should react?

Post by G8GKQ » Fri Mar 03, 2017 5:13 pm

My next suggestion would be to try it without the touchscreen.

Dave

DG8KD
Posts: 48
Joined: Fri Nov 14, 2014 9:02 pm

Re: How fast the system should react?

Post by DG8KD » Fri Mar 03, 2017 5:23 pm

I´ll give it try.
But the command line is different to the touch screen menu.
I will figure it out.

Thanks for your support.

Rainer

DG8KD
Posts: 48
Joined: Fri Nov 14, 2014 9:02 pm

Re: How fast the system should react?

Post by DG8KD » Fri Mar 03, 2017 7:41 pm

Hi,

Problem solved!!
It was the power supply !!! Sometimes it drops under 4,87 volts and then the PI became a bit unstable.

Important to know:

The Raspberry Pi 3 needs 5,1 volts (according to the spec) !!!!!!


(The system overview states 5 v Power in (https://wiki.batc.tv/File:1-1_Block_Diagram.jpg, this may be corrected )

The official power supply from the foundation delivers this voltage.
https://thepihut.com/products/official- ... wer-supply

Input Voltage Range 90-264VAC
Input Frequency 47-63Hz
Input Current 0.5A Max
Inrush Current No damage and IP fuse will not blow
AC Inlet UK, Euro, Aus & US changeable heads
Output Voltage +5.1Vdc
Minimum Load Current 0A
Nominal Load Current 2.5A
Nominal Output Power 13W
Output Regulation +/-5%
Line Regulation +/-2%
Ripple & Noise 120mVp-p Maximum
Rise Time 100mS Maximum at nominal input
Turn-on Delay 3 Seconds Maximum at nominal input
Protection Short circuit, over current, over voltage
Efficiency 80.86%
Output Cable 1500mm Micro USB B 5 Pin

Even if you are using the USB ports from the PI the voltage will drop if the supply is not sufficient and then can cause problems.
Maybe a solution is to use an external powered USB hub.

So take care of the power supply.

73
Rainer

g8gtz
Posts: 1308
Joined: Wed Apr 07, 2010 6:26 pm

Re: How fast the system should react?

Post by g8gtz » Sat Mar 04, 2017 9:19 am

Thanks and glad you've fixed it - I've updated the wiki page.

https://wiki.batc.tv/Assembling_Portsdown#Power_Wiring

73
Noel - G8GTZ

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