EQDir USB vs Serial

[Earl]

Has anyone used both USB and Serial versions of these and can compare the reliability and stability of each.

I have just moved my Lakeside Focuser over to Serial and It has stopped the following two issues using Ascom Pad.

When the focuser is moving a long distance.

a) Program not responding no longer appears.

The spinning Blue busy cursor also does not appear anymore.

[BlueAstra]

Not quite the same, but I found my direct serial link to my eq6 pro handset totally reliable (via a usb/serial dongle), compared with trying to go through a usb repeater and hub to a hitec usb eqdir module. Of course it could have been the cable or hub quality. I now run a local pc at the eq6 with the eqdir module running direct to the pc. This is much more reliable, but I have still had the odd occasion when slewing has stopped for no reason.

[Helen]

This is a timely discussion Earl as I've just got a HEQ5 Syntrek as my travel/star party mount (decided that dismantling/resetting the EQ6 from the Obs was too much hassle - and its too heavy for me on my own!!). I'm wondering which EQMod route to go down. I thought the PC direct connection might be OK. So I just need a serial/USB adapter. Anyone got recommendations of ones to buy (or avoid!).

Helen

[Earl]

Hi Helen im personally avoiding any USB adaptors Im going Serial.

I have had to many niggles with USB to Serial

edit:

The cheaper USB adaptors on reboot do not always go back to the same COM port, however you can buy some which will Remember what they were last set to.

I have found EQmod to be unstable with USB adaptors and Hubs and my Focuser is much more stable with a serial connection.

I have a label printer at work, which point blank refuses to work with a USB adapter, I tried 3 different PC's and 5 different USB to Serial adapters from the budget ones to the ones with memory in them.

[Helen]

Thanks for this. My problem is that my laptops don't have serial ports - can you buy add-on serial ports?

Helen

[Earl]

Thanks for this. My problem is that my laptops don't have serial ports - can you buy add-on serial ports?

Helen

You can purchase PCMCIA / PC Card Serial adapters but I have only ever seen single port options.

[chrisshillito]

I have found EQmod to be unstable with USB adaptors and Hubs and my Focuser is much more stable with a serial connection.

EQMOD has no idea what physical hardware it is connected to. A true PC serial port, USB-232 converter or USB-TTL converter all appear as windows COM ports to EQMOD. Any "unstability" is therefore most likely due to the limitations within the USB driver/hardware rather than EQMOD itself.

Chris.

[Earl]

Hi Chris

What would cause EQMod to freeze up with a not responding? and constant spining circle, could it be a break in coms via the USB?

[BlueAstra]

A bit ironic isn't it that USB is short for universal serial bus. USB and serial are both serial I believe, but serial includes error checking that may not be implemented in USB.

I used a Prolific (not sure if that's the chipset or the make) USB/serial dongle and it was totally reliable. The main thing to remember is to always plug your USB device into the same socket on the PC. Then it will use the same COM port assignment. My original setup was laptop/usb-serial dongle/10m serial cable/serial-handset cable/handset/eq6. Never had a problem with this setup, driven from the laptop running Starry Night Pro and EQMOD.

I tried an alternate setup of laptop/10m usb repeater cable/powered usb hub/usb eqdir module/eq6. This was not very reliable at driving the mount, but worked OK with guide cam and imaging cam control. I think the hub was the main problem.

I now use a local pc with the usb eqdir module plugged directly into it. The cameras go into it via the powered hub. I then contol the local pc via a network cable and remote desktop software (teamviewer). This works well, but I have had occasional loss of comms with the mount. recoverable though, and not enough to make me want to use the handset, which is another setup step.

[Bulkins]

Apologies if this is not the most pertinent place to raise this.

I am currently looking into using EQMOD and, like many others, have a laptop without a serial port. I had envisaged buying the Hitec Astro EQDIR USB adapter for my HEQ5 and thought that would be a nice simple and effective solution. However (and I may be misinterpreting) this threads seems to imply that a USB connection will not be as reliable as a RS232 connection. Is there any truth in this? If so then that would suggest buying a serial port PC card (and using in conjunction with a 232 adapter such as the Shoestring) would be the most appropriate solution since other solutions seem to require a 232/USB converter, are therefore still using the USB port and are surely still faced with the same fundamental problem.

Can anyone clarify? I'm sure there are many of users of the Hitec adapter and hopefully they can confirm that is a reliable solution.

[martin_h]

I use the Hitec Astro USB adaptors on both a NEQ6 and a HEQ5 through a powerd hub and active USB lead and have never had any problems with drop out or COM port loss.

[Photosbykev]

I use the Hitec Astro USB adaptors on both a NEQ6 and a HEQ5 through a powerd hub and active USB lead and have never had any problems with drop out or COM port loss.

same here on a NEQ6 mount and I have the guide cam and DSLR shutter control through the same hub. The only problems I've had have been down to me rather than the hardware or software.

[focaldepth]

I have the Hitec USB to serial (low voltage) EQDIR connected to the EQ6 directly, without the synscan. (from FLO)

I also have a "Startech 2 Port USB To Serial Adapter - With COM Retention Uk" (high voltage) all via a USB powerd hub fed from my laptop. (from ebuyer.com)

So far no problems at all.

The only, unconnected, issues are using Stellaruim, Stellariumscope and EQmod-ASCOM, it does seem sensitive if not random to the order things get started up in. usually shuting down the 3 apps and restarting them gets me going and it keeps going.

[Bulkins]

Thanks for the replies Kev and Martin. Any recommendations on mains powered USB hubs? These seem to be pretty hit and miss devices.

[BlueAstra]

My earlier problems with EQMOD/EQDIR turned out to be mount power supply related. I've subsequently used all three EQDIR solutions (Hitec USB, Shoestring Serial, USB FTDI TTL cable) and had no problems at all with any. I currently use the FTDI TTL cable, which is the simplest, cheapest and most direct solution. It came from here FTDI USB to TTL Serial Cable + Shield (7 Way) and just requires a serial plug soldering on the end (pin-outs on EQMOD site).

I think the Hitec USB uses a Prolific chipset for the USB-Serial conversion within the box. The FTDI cable uses a FTDI chipset in the USB plug. Both are USB based, so have length restrictions unless you use a USB repeater. In my case its not an issue since they plug into the scope mounted nettop PC. A USB-Serial adapter/long serial cable/shoestring serial EQDIR module will work over longer distances. I would recommend the Keyspan USB-Serial adapters in this case.

Now I've sorted the power supply issue I've come to appreciate just what a good and useful piece of software EQASCOM is!

[Bulkins]

Thanks BlueAstra. That's certainly a substantially cheaper solution than the Hitec Astro one.

I'm assuming that since I have an HEQ5 Pro that I should be attaching an RJ45 as opposed to a RS232 plug - pinouts as per the very last section of EQMOD

Do you also use this in conjuction with a mains powered USB hub?

Edit - link is wrong - don't know why. However, it's the very last section of the "EQ DIRECT CONTROL CIRCUITS" page.

[RyanParle]

In my experience in using eqmod i have found all of my issues (with EQmod & other stuff too) to be as a result of either USB issues such as hubs being unreliable in the cold & USB to serial adaptors being flakey.

I've always used the FTDI usb to 5v TTL cable directly attached to an RJ45 plug, I didnt use a patch cable for two reasons, firstly the most applicable is that 5v TTL is intended for short distance communication so the lead length should be kept short and the second is that i never solder two lengths of cable together.

when using USB it is important to ensure that you dont try to use one cable for too much equipment. USB hubs are really designed for the home user who will be using devices that arent often used at the same time, also these hubs are not good at handling low temperatures so they can play up at night in the cold.

i find that running my DSLR directly to the laptop is important, also in the past i have found that my focuser needs its own port on the laptop, the remaining hardware gets connected via the USB hub, But i've just made a custom cable to link my focuser direct to USB and so far it seems that i can run this through the hub as well, only testing in real night time conditions will tell for sure though.

[BlueAstra]

Thanks BlueAstra. That's certainly a substantially cheaper solution than the Hitec Astro one.

I'm assuming that since I have an HEQ5 Pro that I should be attaching an RJ45 as opposed to a RS232 plug - pinouts as per the very last section of EQMOD

Do you also use this in conjuction with a mains powered USB hub?

Edit - link is wrong - don't know why. However, it's the very last section of the "EQ DIRECT CONTROL CIRCUITS" page.

Sorry, forgot I was referring to my EQ6 mount. You will need an RJ connector for the HEQ5. Double check the pin out configuration. I use a Maplin triangular shaped 7 port usb powered hub at the mount. Apparently the size of the buffer is what you need to find out, although I've never found any info on this. You can probe a hub with a MS utility (usbview.exe) to find out its buffer size.

[Steve 1962]

I've used EQMOD with a 5v FTDI lead with an HEQ5 Pro and an NEQ6....and have had absolutely no problems whatsoever - even when using a powered 4 way USB hub shared with a guide camera, a GPS module and a Logitech handset.

Steve

[martin_h]

Thanks for the replies Kev and Martin. Any recommendations on mains powered USB hubs? These seem to be pretty hit and miss devices.

I use this one - 4 Port USB 2.0 Switching Hub : USB Switches : Maplin

[Macavity]

I've found the RVO USB/HEQ5 EQMod adaptor reliable (touch wood)

Telescope Accessories | EQ MODS | Rother Valley Optics

I've just introduced their 5m active USB cable into the chain:

http://www.rothervalleyoptics.co.uk/5m-usb-2-0-active_d1052.html

No immediate plans to add a hub. So far so good.

Only slight gremlin has been EQMod's preferential detection of Bluetooth's COM port on ONE/TWO of my Samsung notebooks. But I accept that as simply the "way the (Widows) world". If "nothing happens", I quickly check the COM port numbers.

[Bulkins]

Thanks for all the replies - much appreciated.