Meade LX-85 Starshoot No Pulse Driver Cables

[Don Waters]

https://openphdguiding.org/logs/dl/PHD2_logs_dLnf.zip

I have a new LX-85 purchased because CG-5 died and it was the only mount in stock. Just saying in was not my first choice - it was my only choice. I have read that it does have some issues with guiding and drivers.

ISSUE: no pulse received by mount. 

Wrong driver? The camera connects fine; I have not verified any manual guide pulses to the mount. Using generic driver from ASCOM site.

Wrong Cable? I am using the Starshooter cable from camera to mount guide point. (I have seen a posting to use the Meade 505 from PC to base of HDX, so I have ordered one for testing.)

Connections incorrect? Use base of HBX to computer in addition (instead of?) cable from camera to guide port?

I am a beginner with all this stuff, so terms like ST-4, etc. are confusing. Any replies please be very basic.

In the meantime, I will be reading the PHD2 manual and testing cables for manual pulses.

Don Waters

[wave...@talktalk.net]

Hello Don,

After reading the LX85 manual, it's apparent that the cable that connects your laptop to the mount is an extra item you'll need to purchase. This is described in the manual as the RS-232 to Audiostar cable. It has a USB connector at one end for the laptop and an RJ12 type plug for the Handbox. This is how the PHD2 pulse signals get to the mount. Using the Meade Generic (ASCOM) driver should provide guiding without the need for an ST4 cable (from guide camera to mount guide port). The USB-RS232 cables can be purchased ready made (easiest) or constructed from the component parts. Obviously, the latter does require a little electronics insight and soldering skill. Once you have the RS232 connection, following the PHD2 manual should get you going..

Hope this helps.

- Jack

[Don Waters]

Thanks. I have ordered the cable. I must have overlooked that in the manual.

(I remember that my LX200 had a cable that linked the two disparate connectors and a driver. 507, I think.)

I'll let the forum know how this turns out.

Don

[Don Waters]

I have received what is described as Meade 505 cable. 

I have downloaded what is described as Prolific Driver for this.

I plug the cable into the bottom of my HBX and turn on all devices.

I start PHD2 and "Connect" using the Meade Generic Driver.

 PHD2 shows "connected".

To test (daylight), I go to manual guide and get "pulse not detected" error.

Maybe this is just that the manual guide does not work and actual guiding will,  but it does not seem promising. It will be a while before I can try with dark sky, 

Any ideas?

Don

[chris oneill]

From what I understand slew movements and guide pulses are totally different actions. Until you try real guiding it will be hard to tell if it received guid pulses. Also have you installed all necessary ascom drivers needed for pulses guiding?

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[Don Waters]

Some more info.

I watched the YouTube video on this and I have the same cable and setup. What I find, is I have no COM port available. I have no clue how to proceed. When I plug the cable into the USB slot on the laptop, the Device Manager does recognize it and shows some descriptions that I do not understand, but there is no COM port. 

I did download a driver for this, but not sure if it is correct. All of this driver/cabling business is really confusing.

I was able to try guiding tonight and it does not. PHD2 connects and acts like it is guiding but no pulses.

Argh!

Anyone knowing how to get a COM port - info would be much appreciated.

Don

[wave...@talktalk.net]

Hello Don,
When the 505 Serial-USB cable is plugged into a USB port, Windows should asign it a virtual COM port nimber.
This number is vitally important and should appear on the Windows Device Manager listing under Ports (COM & LPT). There could be more than one COM port assignment, so look for the one related to the Meade Serial-USB device.

If there's no such COM port assigned, then there's no suitable driver installed. The Prolific driver you mentioned should do the trick. If reinstalling this driver doesn't fix it, then the driver is suspect. The world of Serial-USB drivers is a minefield. Some work some don't, but if it came from Meade with the cable it should be OK. If you still have issues, concentrate on this driver. Maybe download it (PL2302) directly from Prolific's website.

Once the cable is recognised, note the COM port number and open the Tools button on the PHD2 Connect Equipment/Mount selector.  The ASCOM Meade Generic Settings window pops up. Here, ensure the COM port selector has the same number. That done, your mount should be recognised in PHD2 and show a green light (bottom RHS). Test the connection using the Manual Guide tool in PHD2. Set the manual guide pulse to something like 5000ms. With the Meade Handbox displaying RA/Dec coordinates, you should see these changing rapidly as you press the N/S/E/W buttons on the Manual Guide gui. With that confirmed you should be ready to go.

Cheers

- Jack

[wave...@talktalk.net]

Hello again Don,

After Googling for 'Meade 505 cable', it seems these are sold by various outlets not associated with Meade themselves. That opens the possibility that the Serial-USB chipset in yours is not compatible with the Prolific chip driver you have installed. Did your cable supplier indicate that the cable has the Prolific chipset? Another one to look out for is the FTDI version. A 'Meade 505' cable sold through Amazon uses a Silabs chipset. Each requires the manufacturer's driver.

- Jack

[mj.w...@gmail.com]

Hi Don

Some of these USB to Serials need a two-part installation.

If after the first installation you see a likely looking entry in Device Manager, if it's yellow you Right-Click on it and select "Install Drivers"

Michael

Wiltshire UK

[mj.w...@gmail.com]

Hi Don

Thinking further, don't you already have a USB to Serial cable for your LX200GPS, which should work with the #505  cable plugged into it instead ?

Assuming it is a separate USB to Serial, and a separate #505 cable, not the combined kind ?

Michael

Wiltshire UK

[Don Waters]

Thanks all. 

I realize now my previous total lack of understanding of RS232, COM ports, USB, etc. Reading up I find that RS232 used have real, PORTS in the computer that were hard wired and so worked directly. Going to USB, the USB is not associated 1-1 with any port and so there must be software so that the device can capture the correct signals, therefore drivers. I had no idea that a cable required software, although I do recall that my 507 cable did, but i did not understand why.

After messing with this last night and reading more, I would say that you have hit the nail on the head about a missing driver. as PHD2 shows no COM ports available. As to the 507, I tried it before, but to the mount and not the HBX. On my old LX200 it plugs into the mount base. The new Meade requires the cable be plugged into the HBX (or so I understand). I tried the 507 cable plugged into the Guide port on the new mount and it did not work, but it could be something else. I might not have the driver for that cable installed and/or updated. I will check these options.

I have found Silicon labs has a driver called CP210x USB to UART. I'm trying that as I see that some cables online suggest it. My cable was from Amazon and checking back on it, they said it came with a disc, but did not. I have emailed the seller for info.

Anyway, we have isolated the problem and I have learned a lot (about computers - nothing to do with astronomy) so I should be able to find a solution. 

Does anyone know if it makes any difference if I have more than one driver installed? I mean Prolific, Meade, Silabs, etc. I presume that USB and the device can sort it out.

Don

[Brian Valente]

>>> Does anyone know if it makes any difference if I have more than one driver installed? I mean Prolific, Meade, Silabs, etc. I presume that USB and the device can sort it out.

Hi Don

You should have one driver per chipset that controls the port

VERY generally computers come with one chipset for USB, so you should have one driver. 

if you get an extra port adapter (like USB to serial) you will have the driver for that specific chipset in the adapter. Usually it's pretty clear what is that chipset because it will be advertised as part of the adapter i.e., Prolific, etc. Nowadays those are almost always installed for you when you plug in your adapter, but you may need to install the driver directly.

You want to make sure the port you are using has the appropriate driver for its chipset. So if you have a prolific chipset in your adapter, it should be registered/listed as a Prolific port. 

Generally the computer handles this for you too, but it's something to watch for

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/4f98067a-3926-4a8f-b194-b5d495eaf409n%40googlegroups.com.

--

Brian 

Brian Valente

portfolio brianvalentephotography.com 

[Don Waters]

An Update.

Plugging the cable into the USB and opening Device Manager, I see that this is a Silabs C210X USB to UART as presumed earlier.

Device Manager also showed COM5.

I opened PHD2 and found COM5 when I tried to connect mount. I connected and then tried a manual pulse of 5000 duration I did not see any movement in the mount, but I DID NOT get the pulse error, so it does seem that the the mount is recognized by PHD2. I'm not sure about the manual tool, so I will try guiding when I get a night sky. However, it does look like the basic hardware/software connection problem has been solved i.e., user ignorance. LOL.

Don

[Don Waters]

Michael - regarding your specific question, I don't know. There were many issues and I should try again.  I am pretty sure that is a Prolific chip set and I did not have the driver installed (I thought I did.) Anyway, it might work fine to connect the 505 to the base of the mount, but another post I read with a similar problem solved it by using the HBX connection. I know on my CG-5, the HBX connection is required for ASCOM, so I made the assumption here as well.

On Wednesday, May 26, 2021 at 8:20:34 AM UTC-5 mj.w...@gmail.com wrote:

[wave...@talktalk.net]

Don said:

I see that this is a Silabs C210X USB to UART

Then you'll need This Driver

- Jack

[mj.w...@gmail.com]

Hi Don

The #505 connects to the Autostar/Audiostar  handset - because that's where the "computer" is located.

The #507 connects to the LX200GPS RS232 port in the mount - because that's where the "computer" is located - the Autostar II handset is just buttons.

If you managed to get your LX200GPS to work with a USB to Serial adapter, use that one - just plug the Meade  #505 DB9 plug into the DB9 on that USB to Serial Adapter.

Again, that assuming your "cable" is actually two cables joined together, not a bespoke USB to RJ 4P4C.

Michael

Wiltshire UK

[chris oneill]

Try watching this video on how to find com port.  

https://youtu.be/5yHSjDK63bQ

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/ea1e454c-0d0c-4d0b-81ff-55afc4876cc4n%40googlegroups.com.

[Don Waters]

Michael:

The plug on the LX200GPS mount is a different size from the 505 cable for the HBX. I don't know the names of the connectors, but one looks maybe 4-wire and one, 5-wire? I do not have them in front of me right now. Anyway, they are different sizes. The 507 is a two-part cable with RS232 and Prolific chip set, The LX85 cable is a single USB-HBX plug with Silab chip in the molded USB connector.

I am waiting to return home and a clear night to test. At least I have PHD2 seemingly recognized after correctly installing the cable driver.

Don

[mj.w...@gmail.com]

"The plug on the LX200GPS mount is a different size from the 505 cable for the HBX."

That's why you have to swap the two Meade cables, but keep the USB to Serial Adapter !!!!

The #505 plugs into the Autostar/Audiostar handbox.

The #507 plugs into the RS232 port on the LX200GPS mount.

Depending on who you talk to the plugs are called RJ11 or RJ12.

The important bit is:

4P4C for the #505, that's 4Pins, 4Connected.

6P4C for the #507, that's 6Pins, centre 4Connected 

Michael

Wiltshire UK

[Don Waters]

To come to closure on this thread:

1. My manual for the Meade LX85 has no mention of the cable connection.

2. Reviewing the history of guiding, I see that the "Guide" port on the base of the mount was originally used with ST4.

However, a newbie like me would naturally expect that to be the guide port.

3. My cable to the HBX requires a driver. The driver was not supplied and so i had to find it. The driver creates the COM port. 

4. Initial tests show that the LX85 communicates well with PHD2. I tested guiding and drift align, bit not other features yet.

5. My initial guiding (without very precise drift) was around 1 arc sec.

6. I have not checked if the mount recognizes its position or if recalibration is necessary for new targets..

So, it looks like this is a credible system.

Don