Hitecastro USB EQ Direct Interface issue

[jiberjaber]

Hi guys (and gals )

I recently bought a Hitecastro USB EQ Direct Interface.  Like most things, I did a dry run, rebuilt a WinXP laptop (Samsung NC20) and connected up ASCOM, EQMOD and the adaptor.  Scope moved as expected and I thought I was already for some outdoor fun with my HEQ5pro and the direct lead.  That's when it all started to go wrong. 

Out side, nice dark night... After I had loaded up the driver, found the COM port, and launched the Test Connect I thought all good.  Moved the scope around - no problems and then all of a sudden after asking the mount to slew it started and then would not respond to the command from the EQMOD/ASCOM slew controls.  Eventually I turned the power off to the mount to avoid a clatter with the scope and legs.  I was able to repeat this more than a couple of times and decided to not try any further with it in the dark.  I assumed it was an issue with the either the USB ports of the laptop or the OS, so rebuilt the laptop with Vista SP2+ and didn't do much else from there. (I was convinced the USB ports had given up on the laptop - its getting on a bit, so the Vista rebuild was one last attempt before I splashed out on a new laptop).

A few days later I decided to revisit the mount and interface in the warmth inside and during the daylight.  I  connected up the interface and was able to get the scope to talk to the laptop (now running a fully clean and up to date Vista install) , but when I selected Rate 4 (or rate 3) and then asked it to move, it would do the same as before, just keep moving, unable to stop the slew unless I either turned off the power or came out of the control, went back in to driver setup and looked for the com port again (which would take 2 attempts).  Once it found the COM port again I could click test connect and immediately the scope would halt and be in control, however I would be then able to lose control as easily as before!

Thinking this must be the USB ports (I tried all 3 on the laptop) and given I was in the study, I thought I would use my main PC and give that a go.  Unfortunately that yielded exactly the same results.  Then hunting around the net to see if there was a similar issue anywhere I came across using the PC Direct mode of the handset, remembering I had a USB to serial adaptor somewhere for a good few years ago, I located that and thought I would give that a go....

To my surprise that worked perfectly on the main PC...... and so I tried the laptop.... perfect control! This is a prolific chipset as well.

So this made me come to the conclusion perhaps the issue resided between the Hitecastro USB and the port on the mount. I dropped the guys at FLO a line (where I got the adapter from).  Martin was great and has sent me a lead to try out and also suggested I ask on here.... so here I am

I have been able to get the mount to misbehave (without trying) with the new lead.  That led me on a hunt again, I have the hitecastro prolific (29/04/2011) drivers installed and no joy... I had more success with the 2013 Windows sourced driver in that as least the mount would move more often than not (but not stop! )  I can find the com port, test connect and I can hear the mount start making its noise but it now will seldom move the mount (and when it does, it wont stop once started).   

I am a bit of a loss here, the USB to serial, RS232 through the synscan handset works fine even uses the exact same older drivers installed and is on the same com port.

EQMOD 1.24g

ASCOM 6 SP3 (6.0.3.0) connected to EQMOD ASCOM EQ5/6

Timeout 2000

Retry 2

Baud 9600

For both the Vista and Windows 7 machines

Prolific driver 29/04/2011 3.3.17.203 port settings 9600,8,N,1,no flow control

I have run the ASCOM diagnostics and I get 1037 matches, 0 fails and 2 warnings (which are about equipment I don't have, filter wheel etc).

One thing I have noticed is that when I launch the test connect from the toolbox, with the Hitecastro adapter, it usually opens blank and then there is a bit of waiting time before the drop down can be selected.  Sometimes it comes up with Connect Error: Timeout as well.  This is not present on the usb to serial via PC direct on the handset - it seems to work first time every time I try it. 

I am almost at my wits end with the adaptors, I have ran out of things to try, surely it cant be that hard!???  I would welcome any thoughts on how I might resolve this.

[Merlin66]

Hmmm

I've been using both the ShoeString and Hitec EQDir modules for a while - on both the HEQ5 and NEQ6...

When you use the PC direct arrangement through the handcontroller which Serial/ USB adaptor do you use at the computer? I use the Keyspan version.....

[wxsatuser]

Just a thought, how are you powering your mount?

Is the voltage ok........double check that it is stable, I would get it to at least 13Volts.

I have heard that comms failures can result from low voltage dips, worth checking.

[jiberjaber]

Hmmm

I've been using both the ShoeString and Hitec EQDir modules for a while - on both the HEQ5 and NEQ6...

When you use the PC direct arrangement through the handcontroller which Serial/ USB adaptor do you use at the computer? I use the Keyspan version.....

The USB to serial lead I use was a generic one I bought from ebay back in 2009 - works a treat which is why I am confused about the Hitecastro leads not working.

Just a thought, how are you powering your mount?

Is the voltage ok........double check that it is stable, I would get it to at least 13Volts.

I have heard that comms failures can result from low voltage dips, worth checking.

Its running from a 12V 10A switch mode supply, the mount works fine with the handheld controller and also from the PC direct through the controller.

[wxsatuser]

Worth a read may be......

Last post is the one you want....

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/4533508/Main/4470282

[jiberjaber]

Worth a read may be......

Last post is the one you want....

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/4533508/Main/4470282

Spot on for the pointer there - that thread didn't show up in my searches!

I looked in to the PSU voltage both off load and on load, off load it is 13.1V and on load 12.75.  I have also carried out the same with a battery with similar voltages (13.02 / 12.8).  So I have discounted power supply capability being an issue. 

The root cause in my case isn't quite the same as the above link, I now have a solution which isn't ideal.  I suspect but without seeing the innards of the adaptor in use in that thread it might be the same issue solved through other means.

When I first set the mount and adaptor up during the day, all them days ago, it worked fine. I have just realised I was using the laptop on its battery not connected to the PSU. 

When it hasn't worked, the laptop has been on its PSU.  So with this new insight and a quick look through the afore mentioned thread I decided on a few tests to see if my thoughts were on the right track.

The root cause is a ground loop between the power supplies of the laptop (or main PC) and the Mount power supply.  This is pointed to by the fact my USB to serial converter is opto-isolated where as the EQ Dir adaptor is not.  Ground loops - the proverbial pain in the rear!

 Root cause is proven by:

1. Run mount of switch mode PSU and Laptop / Main PC of mains, Com port found, mount clicks in to life on connect but CommErr:ER=16777221

2. Run mount of switch mode PSU and Laptop off battery, Com port found, mount clicks in to life on connect EQMOD works without fault.

3. Run mount of battery and Laptop off battery, Com port found, mount clicks in to life on connect EQMOD works without fault.

4. Run mount of battery and Laptop off mains, Com port found, mount clicks in to life on connect EQMOD works without fault.

5. Run mount of battery and Main PC off mains, Com port found, mount clicks in to life on connect EQMOD works without fault.

6. Repeat all the above but using my opto-isolated USB to serial adaptor and EQMod/Mount works without issue. This proves the switch mode PSU is OK for running the mount under EQMod control, just not without opto-isolation.

So solution to the problem, a different power supply for the mount.  This is a rubber glove to fix a leaking pen however as the real solution would have been opto-isolation on the adaptor which would then cover all cases of use   In the good old days if you made an interface to another system you tried to make it fairly bullet proof, I think these days less importance is attached to that which is a shame, but it usually comes with a cost.

Once again my thanks to the guys at FLO for providing me with a additional adaptor to try out in this fault finding.  Top service once again!

I've got a couple of XM21 PSUs which are not switch mode so will probably fair better - they are just not as convenient as the lighter and smaller switch mode PSU.