Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.


COM port cables and Firmware Updates Synscan v3

Recommended Posts

I have one of these


It connects to my mount NEQ6 ok but it doesn't work for firmware updates. It's supposed to be a prolific chipset so I dont know exactly why its not working for me. Has anyone tried this adapter for updates with success? If not can anyone recommend an ebay, amazon etc one that does work?

Also I managed to get an older pc and update the firmware to 3.37 yesterday. Now when I try to align I always get a NPE error. Never had the problem on the old firmware but it may not have been calculating a cone error anyway. Anyone know what might be wrong or how to fix it?

Share this post

Link to post
Share on other sites

Hello & Welcome to the Lounge...

If you are using the Hitec to drive the mount directly (Using a PC & CDC\Stellarium via Ascom), then you don't need the handset.

But if you wish to wish to drive the mount still using the handset, then you will need a USB to serial, but with an RJ11 type connector.

Wishing you clear skies

Share this post

Link to post
Share on other sites

Hi and welcome to SGL.

The Hitec adaptor is only for use in conjunction with ASCOM/EQMOD+CDC or Stellarium control of your mount without the need to use the handset (it replaces the handset)... it cannot be used for handset or Mount software upgrades.

For that you need the following cable: -


And if your PC/Laptop does not have a true RS232 port you will also need one of these: -


as Julian has stated above...

This cable and adaptor can also be used to control the mount from your PC/Laptop via the handset by placing the handset in PC Direct mode.

This emulates the Hitec device, however, it also adds some additional signal delays which can make some functions, such as guiding or camera control, unreliable... there is also a major problem if you also try to use the handset buttons at the same time when in this mode... things can tend to go a bit nuts.

The majority of users choose the Hitec adaptor rather than the PC direct mode.

The NPE error is just telling you that there is a small value of angular misalignment between the RA and DEC axis (which should be at 90deg to each other) currently stored in the handset memory... this can be caused by cone error or mechanical misalignment and/or mount not being totally level.

You should be able to reset the values stored for both CE (Cone Error) and NPE (Non Perpendicular Error) to zero using the handset, however, they will be updated and re-stored when you do a star alignment.

Some people don't worry about it and just accept the error and carry on with the alignment.

This only came about in the v3.35 or v3.36 SynScan release and has caused a fair bit of discussion on the forum... try doing a forum search for NPE error.

I don't think many members actually know how the value is determined by SynScan... but there might be one or two.

I hope this helps.

Best regards.

Sandy. :grin:

Edited by Lonestar70

Share this post

Link to post
Share on other sites

Thanks very much Sandy just the info I needed! I bought one of those adapters you linked and it works perfectly.

I hadn't been able to pin that error down to a firmware update through reading the forum. Glad its not something I'm doing differently probably had the same alignment error prior to the upgrade and just didn't know about it. I'm going to try setting up my mount again to be perfectly level hopefully that will help.

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

  • Create New...

Important Information

By using this site, you agree to our Terms of Use.