USB2 or USB3 ?

[michael8554]

I'm getting occasional laptop "hanging" due to the ZWO 120MM stopping looping for longer than the default 15 seconds window in PHD2.

The ZWO and Canon 6D are on a 10M Mains Powered 4-port cable.

I'll run some long tests during the day with the ZWO on a short USB2 cable.

If that seems reliable, maybe time to get a new long cable.

Question is, are USB2 devices more reliable on USB3 cables?

Michael

[Kev M]

Using USB3 cables will make no difference at all to reliability.

Its just a USB2 cable with additional wires that USB2 doesn't use.

( Assuming both cables are of the same quality ).

 

[TerryMcK]

Use the native zwo driver for the 120 in PHD2 rather than the ASCOM one and loop for 2 seconds. Set it at 8 bit and it will work fine. The 120 is USB2 only so there is no benefit from using a USB3 cable.

[michael8554]

Thanks Guys

Terry, that's how I've been using it for the last 5 years without issues.

If the camera runs fine on a short cable I will replace the long USB2 4 port cable.

USB3 cables should be made to a higher spec than USB2 because of the higher data rate, so for a one-off long term purchase, the question again - is that quality worth buying for USB2 devices ?

Michael

[michael8554]

I started daytime testing today with the setup left plugged in from last use.

ZWO was showing in Device Manager, but PHD2 couldn't connect.

Unplugging and replugging the USB cable cured this, and it looped without hangs for several hours.

I've a feeling that the ZWO grabs some stuff from the laptop every time it is plugged in, so it could show in Device Manager, but not be initialised.

In future I will fire up the laptop with the ZWO unplugged, and then plug it in.

Michael

[JamesF]

On 24/02/2020 at 23:55, michael8554 said:

USB3 cables should be made to a higher spec than USB2 because of the higher data rate, so for a one-off long term purchase, the question again - is that quality worth buying for USB2 devices ?

I'm prepared to be wrong here, but I have a nagging memory that the wires used for data transmission by USB2 are not used at all in USB3, which uses two new sets of wires instead.  It's possible therefore that the USB2-only bits will be no better in terms of signalling characteristics in a USB3 cable than they are in a USB2 cable.

Ten metres is very long for a USB2 cable though, assuming I've understood correctly.  Again from memory the USB2 spec suggests a maximum cable length of 5m and whilst longer runs do sometimes work there aren't really any guarantees.  You might perhaps be better off using a 5m USB2 active repeater cable connected to the PC end with a second standard USB2 cable plugged into that and then into the hub connected to your cameras.

James

[noah4x4]

I will lay a bet your 'laptop hanging' problem is nothing to do with USB. What processor and RAM does it have?

My mini-PC with a 7i5 processor would repeatedly hang until I upgraded RAM from 4Gb to 8 Gb. The problem is if you overload the in-board graphics, a laptop (or mini) will 'steal from system memory that is already choked by the demands of Windows. How much RAM you might need depends on processor and graphics. 16Gb is more comfortable. 

[michael8554]

Thanks James

Sort of confirms my thought that a USB3 cable wouldn't be worth it. 

It's a 10 M mains powered Active cable which comes with a built in 4 port reclocker at the end. An Active Cable and a separate Hub would result in two reclockers next to each other. 

Sorry noah, thanks for taking the time to reply, but I completely disagree. 

Until very recently for years I used this setup without problems on an XP laptop with 2GB of RAM, and many other will confirm that a gaming pc isn't needed for simple slow progs like PHD2. 

Stuff like BYE and Stellarium then probably yes. 

Michael 

Edited February 26, 2020 by michael8554

[Physopto]

I can't say for your setup, but I have always used Lindy Active USB 2  cables without any problems. Other cheap makes invariably failed or did not work at all. (5-10 metre)

I have several different Lindy types. One of which needs to be an 8 metre active followed by 12 metre if I remember correctly. It works up to around 54 metres in total I think, but only tried up to 20 metres. I also have  some 10 metre types, all  by the same maker. None of which have ever not worked unless damaged mechanically.

Derek

[Waldemar]

This USB-ethernet converter solved all problems I had with USB 2 and 3 connections: 
https://www.silextechnology.com/connectivity-solutions/device-connectivity/ds-600

It can handle 4 USB2 plus 4 USB3 connections. The ethernet cable can be max 100 meters long.

[noah4x4]

6 hours ago, michael8554 said:

Sorry noah, thanks for taking the time to reply, but I completely disagree. 

Until very recently for years I used this setup without problems on an XP laptop with 2GB of RAM, and many other will confirm that a gaming pc isn't needed for simple slow progs like PHD2. 

Stuff like BYE and Stellarium then probably yes. 

Michael 

XP and Windows 10 are entirely different. Windows 10 will itself  gobble 4Gb of RAM.  A Windows XP laptop with slower processor and lesser RAM can often outperform a newer laptop. Windows 10 is ghastly resource hungry.

I spent a year blaming WiFi and USB for my Windows 10 computer hanging when running astro programs and  consequently spent a huge amount of money on powered hubs, active cables, WiFi extenders etc. Eventually, the simple addition of 4Gb RAM (£30)  to give me 8gb fixed it. Then I upgraded to 16 Gb and it flies.

All I am saying is if you can't resolve your problem by other routes, borrow a faster laptop with more RAM and at  least eliminate this possibility. 

[michael8554]

Derek, Waldemar, I've read good things about Lindy kit and Ethernet USB converters

Thanks noah, I buy your W10 scenario. 

Michael 

[noah4x4]

1 hour ago, michael8554 said:

Derek, Waldemar, I've read good things about Lindy kit and Ethernet USB converters

Thanks noah, I buy your W10 scenario. 

Michael 

It's from similar practical experience Michael.

The problem with modern laptops and mini-computers is to keep costs low their on-board graphics 'steal' system resources (like RAM). Some, like the budget end Intel NUCs natively have only 4 Gb RAM. Of course, if Windows 10 has gobbled most of your available resources, then the PC looks to your even slower HDD (SSD is better).  A quite modest APP (like PHD) can push you over the brink and the system then inexplicably hangs.

However, some recent astro APPs are very resource consuming (example Celestron CPWI). My camera ran fine with 4Gb RAM with SG Pro until I added CPWI. As I said earlier, I then blamed USB/WiFi and unnecessarily spent £££££'s upgrading WiFi, when an upgrade to 8 Gb was all that was required. This problem with Windows 10 bloatware is why so many proprietory (all in one box) solutions use the far less resource greedy Linux O/S. Shame Windows 7 is no longer supported by Microsoft! 

One other point of possible note. I was running my camera with either Atik Infinity software and/or Sequence Generator  Pro. When learning the more challenging SG Pro, I was using Infinity to secure close(ish) focus as its FWHM focus tool is easy to use then switch to SG Pro to enable autofocus and benefit from its superior HFR methodology.  SG Pro requires ASCOM camera drivers. I found that if I closed SG Pro and switched to Infinity, my computer will  invariably hang. I attribute this to it getting confused over drivers. My point  here is that a laptop that regularly hangs can be attributable to more than USB cables. But my experience with USB2 was poor beyond 5 metres, even with hubs/active cables. With USB3 it was 3 metres with my data hungry camera. Good luck, hope you find a solution. But do consider the limitations of your RAM.

Edited February 26, 2020 by noah4x4