Re: Canoscan Lide 210 Scanner
On 10/30/2014 3:16 AM, Johann Spies wrote: > This is not Debian specific, but as I experienced it on Debian and > initially thought that it might be a Debian problem, it may help some > other users. > > I recently bought the scanner specified in the subject line after > reading that the saned team claims it has "complete" support. I first > tried it out on my Desktop which has something like 8 usb2 ports. I had > limited success and was frustrated. Then I took it to work and tested > it with my work laptop with 4 usb2 ports and it worked without a problem. > > At home I tested it on my other Debian laptop which have two usb3-ports > and two usb2 ports. On the USB-3 port I experienced the same problems I > had on my Desktop. Moving the connection to a usb2-port everything > worked as expected. > > My thought on this is that on the Desktop there was not enough power > coming through the usb-port and on the usb3-port there the power was too > much. > > This scanner only works with the electricity it gets through the > usb-connection. > > Regards > Johann > > -- > Because experiencing your loyal love is better than life itself, > my lips will praise you. (Psalm 63:3) There is no such thing as "too much" power, as long as the voltage is the same. The scanner will only draw what it needs at a particular voltage. As long as the source provides sufficient power, it should work. "Too much power" would be like plugging your TV into a 15 amp circuit and it works fine. But plugging it into a 20 amp circuit (more power available) would cause it not to work. It doesn't happen. Jerry -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/545261dc.7020...@attglobal.net
Re: Canoscan Lide 210 Scanner
On 10/30/2014 03:16 AM, Johann Spies wrote: This is not Debian specific, but as I experienced it on Debian and initially thought that it might be a Debian problem, it may help some other users. I recently bought the scanner specified in the subject line after reading that the saned team claims it has "complete" support. I first tried it out on my Desktop which has something like 8 usb2 ports. I had limited success and was frustrated. Then I took it to work and tested it with my work laptop with 4 usb2 ports and it worked without a problem. At home I tested it on my other Debian laptop which have two usb3-ports and two usb2 ports. On the USB-3 port I experienced the same problems I had on my Desktop. Moving the connection to a usb2-port everything worked as expected. My thought on this is that on the Desktop there was not enough power coming through the usb-port and on the usb3-port there the power was too much. This scanner only works with the electricity it gets through the usb-connection. Regards Johann -- Because experiencing your loyal love is better than life itself, my lips will praise you. (Psalm 63:3) As a retired engineer, I can tell you that "the power was too much" is ridiculous. Assuming the voltage is correct--which it ought to be, to keep from blowing up whatever is plugged into the port, there cannot be "too much" power. Power is determined by voltage and current: voltage (in volts) times current (in amps) equals power (in watts). The voltage, we have determined here is constant--5VDC. The current is determined by the resistance of the load--current = voltage divided by resistance (in ohms). Any electrical device has resistance. In this case, it's your scanner. You have no way to measure that resistance, but it will be determined by the characteristics of the device. For instance, there is probably a passive resistance, when the scanner is not scanning. Then there will be a dynamic resistance, a value determined by the amount of current the scanning motor requires. (Actually determined by the number of turns and size of wire in the scanning motor.) You may be correct, however, in thinking that one computer has too little power. If the load--i.e., the scanner--tries to draw more current than the power supply can produce, the voltage will drop, and the scanning motor will not run, or the lamp may become too dim, or some combination of things. --doug -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/54525670.9060...@optonline.net
Re: Canoscan Lide 210 Scanner
> See the following bug report > https://bugs.launchpad.net/ubuntu/+source/xsane/+bug/1247371 > > Thanks. I did not see it before. That confirms what I was experiencing. Regards Johann
Re: Canoscan Lide 210 Scanner
On 30 October 2014 10:56, Joe wrote: > On Thu, 30 Oct 2014 09:16:42 +0200 > Johann Spies wrote: > > It is astronomically unlikely that the USB supply voltage would be too > high, as almost certainly, the same supply is used inside the computer, > and a 5 Volt rail can't go any higher than 5.25 before other things > will stop working. > Not the volt but the current maybe. According to this website( http://www.extremetech.com/computing/115251-how-usb-charging-works-or-how-to-avoid-blowing-up-your-smartphone) the current on USB2 can be up to 500mA (0.5A) while in the case of USB3 it is 900mA (0.9A). Regards Johann -- Because experiencing your loyal love is better than life itself, my lips will praise you. (Psalm 63:3)
Re: Canoscan Lide 210 Scanner
See the following bug report https://bugs.launchpad.net/ubuntu/+source/xsane/+bug/1247371 There seems to be a problem with USB 3. I have the same scanner (210) but the error doesn't occur after each scan, it seems to be more irregular, but certain settings (resolution, color depth, ...) can force it. Since you mentioned that it works fine when plugged it in USB 2 I will check which USB port I'm currently using this evening (my desktop has both of them). Le 30 oct. 2014 à 09:56, Joe a écrit : > On Thu, 30 Oct 2014 09:16:42 +0200 > Johann Spies wrote: > >> This is not Debian specific, but as I experienced it on Debian and >> initially thought that it might be a Debian problem, it may help some >> other users. >> >> I recently bought the scanner specified in the subject line after >> reading that the saned team claims it has "complete" support. I >> first tried it out on my Desktop which has something like 8 usb2 >> ports. I had limited success and was frustrated. Then I took it to >> work and tested it with my work laptop with 4 usb2 ports and it >> worked without a problem. >> >> At home I tested it on my other Debian laptop which have two >> usb3-ports and two usb2 ports. On the USB-3 port I experienced the >> same problems I had on my Desktop. Moving the connection to a >> usb2-port everything worked as expected. >> >> My thought on this is that on the Desktop there was not enough power >> coming through the usb-port and on the usb3-port there the power was >> too much. > > It is astronomically unlikely that the USB supply voltage would be too > high, as almost certainly, the same supply is used inside the computer, > and a 5 Volt rail can't go any higher than 5.25 before other things > will stop working. >> >> This scanner only works with the electricity it gets through the >> usb-connection. >> > Something you could try is a powered USB hub, using a separate 5 Volt > supply. If the scanner works through the hub on the problem machine(s) > with external power applied but not without it, it's pretty certain > that's the answer. Computer USB ports are not all equal in terms of the > maximum current available, and at the moment, this does look the most > likely answer. I'm assuming you're using the same USB cable for all the > tests, at least on USB2, as scanners do shift a fair amount of data and > all USB cables aren't created equal, either. > > I have two devices that came with USB cables with two type-A connectors > fitted at one end, as the 'guaranteed' minimum of 100mA from one port > isn't enough for them. But I've still had trouble, so I use them > through a powered hub every time now. > > -- > Joe > > > -- > To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org > with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org > Archive: > https://lists.debian.org/20141030085635.29711...@jresid.jretrading.com > -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/4cbb0de4-9e61-410a-8a5b-745297253...@gmx.ch
Re: Canoscan Lide 210 Scanner
On Thu, 30 Oct 2014 09:16:42 +0200 Johann Spies wrote: > This is not Debian specific, but as I experienced it on Debian and > initially thought that it might be a Debian problem, it may help some > other users. > > I recently bought the scanner specified in the subject line after > reading that the saned team claims it has "complete" support. I > first tried it out on my Desktop which has something like 8 usb2 > ports. I had limited success and was frustrated. Then I took it to > work and tested it with my work laptop with 4 usb2 ports and it > worked without a problem. > > At home I tested it on my other Debian laptop which have two > usb3-ports and two usb2 ports. On the USB-3 port I experienced the > same problems I had on my Desktop. Moving the connection to a > usb2-port everything worked as expected. > > My thought on this is that on the Desktop there was not enough power > coming through the usb-port and on the usb3-port there the power was > too much. It is astronomically unlikely that the USB supply voltage would be too high, as almost certainly, the same supply is used inside the computer, and a 5 Volt rail can't go any higher than 5.25 before other things will stop working. > > This scanner only works with the electricity it gets through the > usb-connection. > Something you could try is a powered USB hub, using a separate 5 Volt supply. If the scanner works through the hub on the problem machine(s) with external power applied but not without it, it's pretty certain that's the answer. Computer USB ports are not all equal in terms of the maximum current available, and at the moment, this does look the most likely answer. I'm assuming you're using the same USB cable for all the tests, at least on USB2, as scanners do shift a fair amount of data and all USB cables aren't created equal, either. I have two devices that came with USB cables with two type-A connectors fitted at one end, as the 'guaranteed' minimum of 100mA from one port isn't enough for them. But I've still had trouble, so I use them through a powered hub every time now. -- Joe -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/20141030085635.29711...@jresid.jretrading.com
Canoscan Lide 210 Scanner
This is not Debian specific, but as I experienced it on Debian and initially thought that it might be a Debian problem, it may help some other users. I recently bought the scanner specified in the subject line after reading that the saned team claims it has "complete" support. I first tried it out on my Desktop which has something like 8 usb2 ports. I had limited success and was frustrated. Then I took it to work and tested it with my work laptop with 4 usb2 ports and it worked without a problem. At home I tested it on my other Debian laptop which have two usb3-ports and two usb2 ports. On the USB-3 port I experienced the same problems I had on my Desktop. Moving the connection to a usb2-port everything worked as expected. My thought on this is that on the Desktop there was not enough power coming through the usb-port and on the usb3-port there the power was too much. This scanner only works with the electricity it gets through the usb-connection. Regards Johann -- Because experiencing your loyal love is better than life itself, my lips will praise you. (Psalm 63:3)
