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Meade LXD75 Serial Connection Failed?

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#1 jlarysz

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Posted 05 December 2022 - 05:08 PM

The serial connection on my Meade LXD75/10" with Autostar 497 seems to have failed - or gone into hibernation. I've not used the scope for about a month, now I cannot get a response from it. I'm trying to connect with the ASCOM Device Hub (version 6.6) with trace on. Here's what the trace file says:

 

16:54:55.824 ReadProfile               Trace logger enabled: True
16:54:55.824 ReadProfile               Com Port: COM2
16:54:55.824 ReadProfile               Backlash Steps: 3000
16:54:55.824 ReadProfile               Dynamic breaking: True
16:54:55.824 ReadProfile               Guide Rate: 10.077939
16:54:55.824 ReadProfile               Precision: Unchanged
16:54:55.824 ReadProfile               Guiding Style: Auto
16:54:55.824 ReadProfile               Site Elevation: 457
16:54:55.824 ReadProfile               Settle Time after slew: 2
16:54:55.825 ReadProfile               Send date and time on connect: True
16:54:55.825 ReadProfile               Parked Behaviour: NoCoordinates
16:54:55.825 ReadProfile               Parked Alt: 0
16:54:55.825 ReadProfile               Parked Az: 180
16:54:55.825 ReadProfile               Focal Length: 1016
16:54:55.825 ReadProfile               Aperture Area: 810731
16:54:55.825 ReadProfile               Aperture Area: 254
16:54:55.825 Telescope                 Completed initialisation
16:54:55.825 DriverVersion Get         1.3.7.435
16:54:55.825 Telescope                 Driver version: 1.3.7.435
16:54:55.832 InterfaceVersion Get      3
16:54:55.833 Connected                 Get False
16:54:55.833 Connected                 Get False
16:54:55.835 Connected                 Set True
16:54:55.840 ReadProfile               Trace logger enabled: True
16:54:55.840 ReadProfile               Com Port: COM2
16:54:55.840 ReadProfile               Backlash Steps: 3000
16:54:55.840 ReadProfile               Dynamic breaking: True
16:54:55.840 ReadProfile               Guide Rate: 10.077939
16:54:55.840 ReadProfile               Precision: Unchanged
16:54:55.840 ReadProfile               Guiding Style: Auto
16:54:55.840 ReadProfile               Site Elevation: 457
16:54:55.840 ReadProfile               Settle Time after slew: 2
16:54:55.840 ReadProfile               Send date and time on connect: True
16:54:55.840 ReadProfile               Parked Behaviour: NoCoordinates
16:54:55.840 ReadProfile               Parked Alt: 0
16:54:55.840 ReadProfile               Parked Az: 180
16:54:55.840 ReadProfile               Focal Length: 1016
16:54:55.840 ReadProfile               Aperture Area: 810731
16:54:55.840 ReadProfile               Aperture Area: 254
16:54:55.840 Connected Set             Connecting to port COM2
16:54:55.912 SendString                Transmitting #:GVP#
16:55:00.932 SendString                Timed out waiting for received data
16:55:00.932 Connect                   Error getting telescope information "Timed out waiting for received data" setting to LX200 Classic mode.
16:55:00.933 SendString                Transmitting #:GG#
16:55:05.944 SendString                Timed out waiting for received data
16:55:06.053 Connected Set             Error connecting to port COM2 - Timed out waiting for received data
16:55:06.565 Connected                 Get False
16:55:07.079 Connected                 Get False
16:55:07.587 Connected                 Get False
16:55:08.103 Connected                 Get False
16:55:08.614 Connected                 Get False
16:55:09.128 Connected                 Get False
16:55:09.643 Connected                 Get False
16:55:10.156 Connected                 Get False
16:55:10.668 Connected                 Get False
16:55:11.183 Connected                 Get False
16:55:11.695 Connected                 Get False
16:55:12.206 Connected                 Get False
16:55:12.721 Connected                 Get False
16:55:13.231 Connected                 Get False
16:55:13.745 Connected                 Get False
16:55:14.260 Connected                 Get False
16:55:14.772 Connected                 Get False
16:55:15.281 Connected                 Get False
16:55:15.786 Connected                 Get False
16:55:16.296 Connected                 Get False
16:55:16.297 Connected                 Get False
16:55:16.298 Connected                 Get False

 

I'm using a Windows 11 computer. The port seems to connect but doesn't respond. The port is set to 9600 baud, 8 bits and no parity. Does anyone have suggestions for what to poke at here?


Edited by jlarysz, 05 December 2022 - 05:21 PM.


#2 Skywatchr

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Posted 05 December 2022 - 09:05 PM

Did you use Win11 with this before?


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#3 Piet Le Roux

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Posted 05 December 2022 - 11:58 PM

Did you use Win11 with this before?

Windows 11 does not have drivers for all serial to USB converters, check in device manager if your converter driver is functioning correctly.


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#4 jlarysz

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Posted 06 December 2022 - 08:49 AM

This configuration and cabling did work on the same Windows 11 laptop a month ago. The device manager says that the serial port is working properly.


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#5 Skywatchr

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Posted 06 December 2022 - 06:38 PM

This configuration and cabling did work on the same Windows 11 laptop a month ago. The device manager says that the serial port is working properly.

Has there been any updates to Win11?  If so, try to "roll back" to a previous driver.

In Win10, every time there is an update, my sound card stops putting out sound. It is still there and "appears" to be working with no conflicts or any other "signs". I roll back the driver, reboot, and it works.  Then I uninstall the "old" driver, then let Win10 automatically reinstall it. After that it works again with the "new" driver from the update.  Strange undecided.gif , but it happens every time there is an update...



#6 DAVIDG

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Posted 06 December 2022 - 11:27 PM

 When I have these types of problems I use a terminal program to send the commands to the telescope . So in this case you can use a program like the old Hyperterm to send the commands to the  497 and see if it responds. I program Arduino so I personally use the terminal built into the IDE to program them to send commands to the 497 to check communication. So if you get two way communication  you know  it is not hardware or a driver issues with the USB port or the USB to serial converter.

   One thing I noticed is the commands being sent start with # which is the terminal character for Meade serial commands. For example the command for the UTC offset is :GG#  but it was sent as #:GG#  I'm not sure if that would confuse the 497 as unknown command or not. Did the ASCOM driver get updated and now  has an error in the format of the commands it is sending ? 

 

               - Dave 


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#7 OzAndrewJ

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Posted 07 December 2022 - 12:46 AM

Gday Dave

I'm not sure if that would confuse the 497 as unknown command or not.

It wont confuse the 497 but can confuse the client program.

I dont like the use of a "#" prefix but several drivers use it.

Basically, on receiving a "#", the internal parser in the Hbx declares an "end of command"

The following ":" means "Start of command"

The leading "#" was used to flush/force unfinished commands

before the new command gets sent ( so it gets processed properly ).

It is rare, but what can happen is the initial "#" flushes gunk from the buffer

and this is read as part of the reply to the following real command.

ie, if the mount is there, it wont be confused, it will still send what it has,

but the response may have crud prefixing its reply.

ie no reply means no reply.

Re using Hyperterm ( or my App ), you can do a loopback test on the cable.

Short the Tx and Rx pins at the end of the cable to see if the cable itself is working first.

Then try it in the Hbx

 

Andrew Johansen Melbourne Australia


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#8 jlarysz

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Posted 07 December 2022 - 06:07 PM

Thanks for all the replies.

 

I have tried a couple of terminal programs to send serial commands (free programs found on Google). They both timed out waiting for a reply. I sent the two command strings I found in the trace log (see above) including the leading "#".  I did not know what the ":" and "#" characters meant - that will be the next thing to try.

 

Is there a serial port reset command buried somewhere in the 497 menus?

 

The last resort will be to buy a new 497 unit and see if that works. It's an expensive way to try something.


Edited by jlarysz, 07 December 2022 - 06:11 PM.


#9 OzAndrewJ

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Posted 07 December 2022 - 07:07 PM

Gday jlarysz

 

Have you tried the loopback test to ensure the USB cable itself is working???

If so, also look into the socket in the Hbx

sometimes, one of the connectors gets stuck down or out of place

and can normally be freed with a fine pin or hook

( i use a straightened fish hook at times  )

Lastly, if you can make a temporary 4P4C plug

then make one up that shorts the Rx to the Tx pins inside the Hbx

Plug that into the Hbx and then turn the Hbx ON

If the comms in the Hbx are working, this will put the handset into

a self diagnostic mode, ie you know the Hbx comms are working

 

 

Andrew Johansen Melbourne Australia



#10 DAVIDG

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Posted 07 December 2022 - 07:58 PM

 Here is  a link to the all the serial commands   All the comands start with a ":" and end with "#" 

 On my serial to USB converters there are LEDs to show when characters are being sent and received that blink with the transmission. If yours has these and you can tell if data is being sent. As Andrew stated you can also try the loop back by attaching the TX to the RX line to see if  converter is working and terminal program is configured correctly. 

 

 

           - Dave 



#11 jlarysz

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Posted 08 December 2022 - 10:54 AM

DavidG - the link to the Meade command set has dropped off. Would you re-post please?



#12 jlarysz

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Posted 08 December 2022 - 12:29 PM

OzAndrewJ - I'm not clear on getting in to diagmostic mode on the 497.

 

1:  Why do I need a 4P4C plug and where is it going to?

 

2:  The HBX plug is 8P8C. I can make up such a plug with Tx and Rx shorted. Do I need any other pins connected?



#13 DAVIDG

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Posted 08 December 2022 - 03:35 PM

DavidG - the link to the Meade command set has dropped off. Would you re-post please?

 Try this 

http://www.company7....0CommandSet.pdf

  There are two ports on the Autostar 497, the 4P4C one is the serial port plug   So what Andrew is say is that you make up a cable that plugs into the serial port on the 497 that has the TX and RX lines shorted together. When you power up the 497, the shorted TX to RX lines will cause the 497 to display a message that is it test mode and that tell you that the serial port on the 497 is working. 

 

         - Dave 


Edited by DAVIDG, 08 December 2022 - 03:44 PM.


#14 OzAndrewJ

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Posted 08 December 2022 - 03:51 PM

Gday jlarysz

 

1: Why do I need a 4P4C plug and where is it going to?

2:  The HBX plug is 8P8C. I can make up such a plug with Tx and Rx shorted. Do I need any other pins connected?

 

To put the Hbx into test mode, it needs to be connected to the mount

unless you also want to make a temporary power supply.

Basically, if you cannot connect your PC to the handset,

it could be the handset at fault or the PC cable.

As such, to test the Hbx side of things

you make a dummy plug that plugs into the handsets rs232 port ( 4P4C )

ref piccy

This plug simply shorts the Tx to Rx lines.

On booting, the handset always sends data ( IIRC its an "X" ) out on the Tx line

and if it sees this mirrored on the Rx line, it goes into test mode.

Soooooo, if it does go into test mode, you know it sent AND received data

ie it is working

 

Andrew Johansen Melbourne Australia

HBxTest.jpg

 

 

 

 



#15 jlarysz

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Posted 08 December 2022 - 06:56 PM

1:  I failed to do a loopback test - I just don't have the hardware bits and pieces any more. I tossed all my serial stuff about 10 years ago when I was sure I'd never see a serial cable again.

 

2:  I squeezed up an RJ9 plug to short out the 2 pins indicated in the picture. Just in case I misinterpreted things, I squeezed up another plug with the other two connections shorted out. Neither plug would put the 497 handset into diagnostic mode. What does diagnostic mode look like anyway?

 

3:  Putty will open up a window on the COM2 port, the port I am using for my serial connection. I can't get any response to anything typed in the window.

 

4:  The Serial cable is made up of 2 parts: Part A is a USB plug to a male DB9. Part B is a female DB9 to a 4P4C plug. I think that Part A contains the chip that responds to Windows and  that is what Putty is seeing, so I can assume that this bit of cable is OK. PartB could still be faulty.



#16 jlarysz

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Posted 08 December 2022 - 07:01 PM

DavidG - thanks for the protocol set. At least now I can see what :GVP# is supposed to do.



#17 jlarysz

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Posted 08 December 2022 - 07:21 PM

I found and old female DB9 plug with some cable attached. I shorted out pins 2 and 3 and tried a loopback test on the active part of the serial cable - PartA. It didn't work. Do I need a signal return connection in the test plug?



#18 OzAndrewJ

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Posted 08 December 2022 - 07:44 PM

Gday jlarysz

 

I squeezed up an RJ9 plug to short out the 2 pins indicated in the picture. Just in case I misinterpreted things, I squeezed up another plug with the other two connections shorted out.

In the picture i posted, the sketch is looking into the socket

 

What does diagnostic mode look like anyway?

The screen starts as per normal then goes "Press Press" on the top line

You then just press the keys

It has a bug in that it doesnt properly list what keys to press

but its basically top left to bott right.

That said, if it doesnt get there, and just boots normally

that indicates the Hbx has a problem.

 

I think that Part A contains the chip that responds to Windows and  that is what Putty is seeing, so I can assume that this bit of cable is OK.

Not always. If the chipset is recognised by windoze, then shorting Tx and Rx

in the DB9 connector should get a response.

If it does, plug in the extension with the 4P4C connector and retry but this time short

the connectors in the 4P4C

ref https://www.cloudyni.../#entry12183959

for a piccy of how it should be wired

Andrew Johansen Melbourne Australia

 

PS i see you tried a test shorting the DB9 pins and that didnt work either.

If that wont register a loopback, then nothing downstream will work


Edited by OzAndrewJ, 08 December 2022 - 07:45 PM.


#19 jlarysz

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Posted 09 December 2022 - 01:51 PM

I have a DB9 breakout connector coming. Right now I'm hoping for a cable problem - they all fail sometime.



#20 OzAndrewJ

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Posted 09 December 2022 - 04:12 PM

Gday jlarysz

To test the cable with the db9, its easy to just use a pin to short the 2 pins

No breakout box reqd.

The system only uses Tx/Rx and ground so is pretty simple.

 

Andrew Johansen Melbourne Australia



#21 OzAndrewJ

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Posted 09 December 2022 - 05:51 PM

Gday jlarysz

Just thinking

You mentioned the loopback test failed on both the cable and the handset.

That seemed odd to me

You also mentioned a 497 Autostar

Is it really a classic Autostar, or a 497EP/Audiostar ???

If the latter, it uses a totally different method to do diagnostic tests

and has much more functionality, but requires a different boot sequence

and also requires a special Hbx cable ( as it also tests al the clocks etc

for motors and Aux )

 

Andrew Johansen Melbourne Australia



#22 jlarysz

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Posted 10 December 2022 - 11:51 AM

OzAndrew - It is a 497/EP handset. The special cable might be a problem; man I cake one up myself?

 

Right now I'm suspecting the serial cable assembly. I'll check it's pinouts and connectivity when the wife tires of finding me things to do.

 

The mystery is that it's a static cable; it worked once, and there's not much to break in there.



#23 OzAndrewJ

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Posted 10 December 2022 - 04:16 PM

Gday jlarysz

If it starts with 497EP it could be a 497EP or Audiostar so what firmware does it have ????

I will double check the code if reqd, but to simply test the rs232 port

all you would need is the 4p4c loopback you already have.

( Use the one that matches my above piccy, assuming the piccy is 

drawn when looking into the socket in the handset )

You can simply bypass the motor and Aux tests, so no need for a special Hbx cable

 

If you want to try, let me know and i will write up a quick precis

 

Andrew Johansen Melbourne Australia



#24 jlarysz

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Posted 10 December 2022 - 07:51 PM

OzAndrew:  I would like to try testing the 497. My firmware is A1f7 - the most recent I could find on the web.

 

I've ordered a new USB-Serial cable. I can't get my existing one to pass a loopback test and it's a silly thing to be doubtful about.

 

I'm using Putty for the loopback test. I see the transmit character whether not pins 2 and 3 on the DB9 are shorted so I'm sure I'm seeing the transmit character. I don't ever see a receive character. I've looked for a voltage blip on pins 2/5 and 3/5 too - nothing. I wish I had my old responsive analogue needle voltmeter, but that went out with my stock of serial connector bits.



#25 OzAndrewJ

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Posted 10 December 2022 - 08:20 PM

Gday jlarysz

I would like to try testing the 497. My firmware is A1f7 - the most recent I could find on the web.

OK, A1F7 means its an Audiostar, but A1F7 does appear to still have the diagnostic.

( Tha latest firmware is A4S4, but patched A1F7 is what i suggest for all the older

models of Meade scopes like ETX, LX90, LXD55/75 etc

A4S4 and A1F7 + patches can be found on the StarPatch site )

 

To test the Hbx, put the loopback plug into the 4P4C socket in the Hbx

( Again use the one that shorts the pins ( 3,4 in the plug ) as per above piccy )

 

Now hold down the <Mode> and <Slew Up>  keys and boot the mount

( Unlike safeload, you use the upper slew key here, not the scroll key at the bottom )

 

You should hear a beep then

The screen will say something like

"497EP D QC Test" and the map led will flash a few times

and the LCD contrast will go through its range

It will then beep and fill the LCD with the alphabet

then clear and fill the LCD with the reverse alphabet

 

It should then say "EEProm Test" and "Pass"

It should then say "RA Loop Back" and "Fail" and beep

This fail is because you dont have a loopback on the RA clock

so simply press "?". It will say "Bypass" and keep going

It should then say "DEC Loop Back" and "Fail" and beep

ie failed again so just hit "?"

It should then say "AUX Loop Back" and "Fail" and beep

ie failed again so just hit "?"

At this point watch carefully as it goes fast but it should then say

"RS232 Loop Back" and "ByPass" then move on

If it doesnt beep with "Fail" it means the rs232 worked

It then displays "Keypad" and a character for each key

As you press the keys, they disappear from the screen

Once done, the handset reboots

 

Sooooo, if you dont see "Fail" on the rs232 bit, the handsets comms are working.

 

Andrew Johansen Melbourne Australia


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