Pxi 2575 high resistance

I am having problems with the resistance across relays on a PXI-2575 increasing over time (faster than expected). I am using a PXI-2575 in combination with a PXI-4070 for manufacturing test. In some cases I am looking for an expected short circuit. The data sheet states that with no voltage applied (which I have none) I should see < 1 ohm for up to 2.5 million cycles. However, I am seeing upwards of 16 ohms across a particular relay after ~2500 cycles in many cases. I have a total 6 of these setups, and I am finding myself replacing PXI-2575 cards after less than 1 year of service due to these high resistances.
To prove to myself that it is the switch matrix (after measuring the UUT with a Fluke DMM) I used the following setup:
PXI-4070 DMM
PXI-2575 Switch Matrix
LFH200 Cable
24 awg wire
The PXI-4070 is configured for a 2-wire resistance measurement. The PXI-2575 is configured as a 95x1 2-wire mux. The DMM + terminal is connected to pin 46 of Backshell 0 (CH22+) and the - terminal is connected to pin 47 of Backshell 0 (CH22-). A small 24 awg jumper wire is used between pins 23 and 34 of Backshell 3 (COM+ and COM-). On a brand new switch matrix I see ~0.16 ohms using this test. On the most recent one I pulled out of production use, I saw ~16 ohms initially, with it falling to ~5 ohms after leaving it connected for about 5 minutes.
I am up to 4 PXI-2575 cards that suffer from this issue. According to the data sheet I should not be seeing this. Any help would be appreciated.
Thanks
Jonathan Rice

Steven
Thanks for the reply. I have done some more testing as you have asked. I realized I actually have 11 PXI-2575's, recently purchased 2 spares, and 3 more for new test equipment. They are all used in an identical manner.
We have made a total of 3 purchases. The first was for 6 PXI-2575's, the next was for 2 (spares), and the final was 3. With all of the swapping around, I am not sure where these failing ones came from at the moment, other than to say they were not part of the most recent purchase of 3. I am more than happy to provide serial numbers, if you can tell me which of the stickers on the board is the serial number. There are two identical looking stickers, one on each of the boards, that have different serial numbers on them.
Below is the data I have collected. Cards 5 & 6 can be considered "good" cards. Note that their readings did not change from their initial readings. They are from the most recent batch. We have no examples of cards with lots of cycles on them that do not exhibit this behavior. Prior to attempt 1 the cards had been powered off and removed from chassis anywhere from days to months. Between attempts 1 and 2 several switch cycles were performed and power was cycled on the PXI and the PC.
*All readings are in Ohms.
Below is a diagram of the setup I am using to test the switch matrices after they fail in the field.
Installing a new PXI-2575 immediately resolves the issue in the test set, and that test set continues to work for another several months.
Any help would be appreciated.
Thanks
Jonathan Rice

Similar Messages

High resistance measurement by 4071 and 2575

I used NI 4071 to measure a high resistance. The resistance is 78.6MΩ.
When I use 4071 directly to measure it(2-wire), the result is 78.58MΩ.
The measurement is ok. But wnen I connect the resistance to NI Switch 2575,
the result become smaller, about 76.4MΩ。
It is strange, and how to deal with the problem? Thanks

Hi faili,
I have never witnessed this issue before, so I attempted to reproduce your problem. I used the following hardware:
I PXI-4071 DMM
NI PXI-2575 Switch
LFH200 to 50-Pin DSub Switch Cable
NI TBX-50, 50 Pin Dsub Screw Terminal Block
Short 24-gauge wires between resistors and terminal block
Resistor Combination in breadboard (28 2.7MΩ resistors = 75.6MΩ)
I used the following procedure:
Opened Switch Soft Front Panel
Configured PXI-2575 in 2-wire 95x1 Topology
Connected ch94->com in Switch Soft Front Panel
Wired CH94+ (50-pin DSub pin 21) to one side of 75.6Mohm resistance, CH94- (50-pin DSub pin 22) to other side
I made the following measurements:
Opened DMM Soft Front Panel
With DMM, measured one side of resistance to other side (after settling) = 75.6MΩ
Wired COM+ (50-pin DSub pin 23) to DMM HI Lead, COM- (50-pin DSub pin 24) to DMM LO Lead
With DMM, measured COM+ to COM- (after settling) = 75.6MΩ
So, I wasn't able to reproduce your issue. Perhaps the above will help. Can you tell me more about your system and how it is configured? Perhaps there is a hidden resistance to GND somewhere in your setup. Looking at the equation, to receive an error of:
78.6MΩ -76.4MΩ = 2.2MΩ (or 2.8%)
you could have a hidden 2.73GΩ path to GND. How are you making your connections to the PXI-2575? Just a thought...
Let me know if you have further questions or if this does not resolve your issue!Chad Erickson
Switch Product Support Engineer
NI - USA

Why is the PXI-2575 not recommended for 2-wire resistance measurements?

The spec for the NI PXI/PXIe-2575 says "Note The NI PXI/PXIe-25-75 is not recommended for 2-wire resistance measurements". Why is this? If I want to perform 2-wire resistance measurements, what would be a good alternative?

It really depends on your measurement. The problem with 2-wire resistance measurements is that the resistance of the wiring and the switch path will be included in your measurement. If you are measuring in the kOhms to MOhms, this should be neglible. But measuring anything smaller will add a large error. That is why 4-wire resistance measurements are recommended. The sense lines can measure the voltage across the part you actually want to measure and an accurate measurement can be made.
This is true for all switches.
My philosophy is to use 4-wire measurements except when checking for an open.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines

PXI-2575 faults randomly

Hi,
I am using PXI-2575 mux with PXI-1044 chasis. I am using .NET C# to control 2575 during a year. In my setup, I am using the mux to read DC voltage or 2-wire resistance generally. It seemed work successfully up to last 2 mounts. Suddenly, some of the channels of mux did not work. I read wrong DC voltage(like 1V instead of 4V or sometimes nothing). Mux is passing the self test in Measurement&Automation, path to COM seems correct but read voltage is wrong. I also hear the swicthing sound. Then, i changed it with different 2575. After a while, some channels of new 2575 were broken. I replaced the broken 2575 with the old broken 2575 and all channels worked successfully.(!) Why this situation happens?
Finally, last day, all the channels of the mux were broken. I could not read anything from COM. I also heared swiching sounds. How can i fix it? When i replace the new one, the new one works succesfully. What is the problem?
Any help would be appreciated.

Knights Who Say NI wrote:
Hey unver,
The self test feature only verifies that the digital backend of the module is functional. The 2575 does not have path resistance circuitry.
Most likely, your relays have reached end of life. You can check the number of cycles in the relay tab of the Switch Soft Front Panel. Note that the number of cycles before failure is largely a function of the reactance of the circuitry plugged into the module; relay cycle life before failure is listed for a purely resistive load, so it's likely that the number of cycles is much less than those figures listed in the specification sheet.
For example, if you're muxing through channels on the 2575 taking voltage measurements, the ~200pF capacitance of the DMM pluss the 50pF per foot of cable is going to store whatever currently connected voltage potential is and then rapidly dissipate the stored charge while the next channel is connecting. When this occurs, there is a relatively large inrush current. Likewise, if your DUT is inductive, the current running through a particular connection will continue to flow as the relay opens due to the same current pushing across a higher resistance (an open relay, instead of closed)...
An easy method to reduce the connect capacitance is to add a couple hundred ohm series resistance to your voltage channels. Likewise, adding a flyback diode to each channel will prevent overvoltage on inductive loads. The flyback diode will also work for the 2-wire resistance, but note that the series resistance won't (it will add to your measurement). To solve this problem, I recommend 4-wire resistance measurements with 200 Ohm series resistors (or whatever) on each leg. The additional series resistance does not affect the measurement when performing 4-wire resistance measurements.
Of course, I've jumped the gun a bit, so first, a little troubleshooting. You obviously have a DMM, so let's set it to resistance and plug it into either side of the suspect channel. Then cycle the relay a few hundred times and see if the resistance is consistent on each closure. If it varies greatly, the relays have probably reached end of life. For the voltage readings to be off 3 volts, the relays are going to need to exhibit some pretty enormous closed resistance values... something like 10MOhm... if this is the case, then the relay current/voltage limits have likely been exceeded.
I also recommend scoping the inrush current with an oscilloscope and a series 0.01Ω resistor. Likewise, measure the flyback voltage when opening the relay with a different channel on the same scope... obviously, you'll want to do this with your 2575 plugged into the DUT and operating in its normal environment...
From your description, I'm almost certain the troubleshooting steps will indicate one or more relays have failed. If I had to guess, I'd say it's K15.
Hi John ,
I think this is not the case. Because, highest switch usage is 117(I think this is very very low) and I am doing the voltage measurements over 10kOhm resistance. Hence, capacitive effect is also not the cause. After i had written my previous message, i prepared a basic set up that applies 5 volts one by one by one to all of the 98 input ports of the broken 2575 and reads the com port with NI6259 daq device. I did this process many times with different time periods. As I guest, the device worked successfully at all the tests. Hence, cause of the problem is different and i still need a help.

Looking for LabVIEW driver for Agilent (HP) 4349B High Resistance Meter

I've been looking for a LabVIEW driver for Agilent (HP) 4349B High Resistance Meter.
Does anyone have one?
Thanks,
Avner

Hello,
It looks like you'll get a reply by Friday; if not repost and I'll follow up for you
Thank you,
JLS
Best,
JLS
Sixclear

PXI-2575 minimum load

I work on new project. I will use multimeter PXI-4070 with switch mux PXI-2575. The multimeter will measure voltage on differents tests points of a circuit in test. The input impedance of PXI-4070 are 10Mohms in measure voltage mode. So the current in relays of PXI-2575 will be very low <2.4uA. All voltages to measure are between 0.5VDC et 24VDC. There are also a measure of 8VaC and 16VAC.
The relay minimum load in datasheet of PXI2575 FEV2008 are "10uA at 10uV DC".
The relay minimum load in datasheet of PXI2575 APR2009 are "20mV/1mA".
My questions:
What the minimum load change in 2009 or it's a error in documentation?
What the real signification of "20mV/1mA"?
The current must be always greater than 1mA or periodicly greater than 1mA?
The voltage are voltage to init contact or the voltage must be always greater than 20mV?
What a current less than 1mA decrease life of relay?
If I measure AC voltage what the consequence on the measure when the current are between -1mA and 1mA?
Thank you!

How is this related to the Excel add-on program called 'Measure'. I think you should post to the multi-function DAQ board.

Why would a PXI 4071 measuring resistance countinue to increase the measured valued for each measurement?

I have a PXI-4071 DMM and I am measuring a connection in the UUT. The value should be around 0.3 ohms. The program (exe) will run aprox. 20 times and during these 20 runs the measured value will progressively increase until is is over the limit of 1.5 ohms. If I shut down the exe and run the VI as a standalone (continuous loop), the resistance will gradually come down to 0.3 ohms. I then close LabView and restart my exe and the readings are normal (0.3) but then continue to increase until they are over 1.5 ohms. This process has been repeatable for the last week. I have attached the code I am running. What could be the problem with the DMM code?
Attachments:
DMM_MeasResistance2.vi ‏64 KB

Uninitialized shift registers are a good thing to check for such a problem. Do you see the same response with a soft panel and your DMM? if not then it is in code. Uninitialized shift registers would start at 0 (default is usually 0) and will retain their values from run to run. Just a possibility dont have LV up right now so I cant check the code sorry,
Paul
Paul Falkenstein
Coleman Technologies Inc.
CLA, CPI, AIA-Vision
Labview 4.0- 2013, RT, Vision, FPGA

Any reason to scan PXI-2575 and SCXI-1127 in a particular order?

Hello-
Is there any reason to prefer one scan-list order over any other? specifically is it better to scan through ch0, ch1, ch2, etc rather than randomly?
It doesnt seem like it would matter.. but many DAQ devices behave strangely if you scan them in ascending order (eg 0, 1, 2) and thus I always scan them in descending (e.g. 7, 6, 5, ...)
thanks-
brad

Brad,
Simply based on the switch modules, there should be no difference in which scan list is prefferable.
Can you elaborate on the strange behavior you have seen on some DAQ
devices? The only interesting behavior I can recall that may be
fixed by scan order is when certain channels are saturated and "ghost" onto other channels. If this is the case, follow the steps in the linked KnowledgeBase to remedy the problem.
What data acquisition device are you using along with your switch modules? What types of signals are you measuring?
Have a great day!
Travis W

PXIe acquiring and disk streaming speed

Good evening,
I need to acquire and stream to disk the status of N.8 digital lines at 100 MHz clock, idest 100MBytes/sec data rate, in continuously mode (without data loss) for five minutes.
I've thought to a PXIe configuration with:
PXIe 6544 High speed DIO,
PXIe 1071 Chassis,
PXIe Controller with solid state H.D. option.
Is that configuration enough?
Thanks.
Natalino Roberto

Hello Roberto,
According to NI PXIe-6544 specifications, you should be able to achieve typical data streaming rates 400 MB/s for acquisition and 400 MB/s for generation. So, you shouldn't face with any issue from this side.
Does your application provide an host interface communicating with embedded application? If doing so, you may need to design your application according real time guidelines.
Let me know if you need help or additional assistance.
Have a nice day.
Matteo C. - Test Engineer

How to realize PXI-IVi

My Dear friends:
        I feel very blue. Could you help me?
        The case is: We have had a suit of ATE, based on PXI2575, PXI 2569, PXI 6723, PXI 4070. In addition, the TPS developed on MFC has been finished by others.
Now, my tutor asked me to study of “interchange of instrument” based our ATE. I look up some material on the Internet, some books in the library and read some papers. However, it takes no effects and some information is opposite. Here are always some questions puzzling me：
The difference of VISA lib and VXIplug&play drivers? Can we control the instrument cards only by the VISA lib and specific SCPI sentences? You know that the instrument vendors only supply us with driver programs but SCPI, so that we can only use the VISA functions. How can we solve the problem?
What’s more, even if we can use VISA lib and specific SCPI to control the instruments from the vendor, can we use them to control the instruments supplied by other vendors?
The standard of VISA and IVI? Is IVI built on the basis of VISA lib or the VXIplug&play drivers?
Our programs encapsulates “Class CDriveFunc”(the affix) and we can call the functions in other places. Then I only need to set the logic names adapted to the instruments (such Dev12-PXI 2575) and it will make the equipment to operate well.
Can you tell me our program is based on IVI or VISA lib?
Do our TPS realize the IVI ?
Giving that my ATE is based on IVI, does it mean that if my ATE is installed with another compatible instrument card, my TPS will not be modified and I only need to change the relevant logic names of the instrument cards to make the TPS work well?
If I only need to convert the logic names, which place is allowed I to set them? In the MAX of NI, whether need I develop a platform? Another case is that if my instrument card is not from NI corporation, which measures should I take?
Can my ATE based on IVI adapt to any platform, such as VXI, PCI, even GPIB? And if I want my ATE based on PXI to work well based VXI or PCI, what can I do?
If my ATE used the PXI controller, does it mean that I must install the NI-VISA? How can I guarantee my ATE used by another board work well?
If the board I used does not belong the standard class, such as PXI 6723(AO board), boards for communication(RS-232), what need I do?
8.       What differences are between the Labview/CVI, measurement studio and VC++?
My development is VC++ 6.0, can it support IVI?
At last, I am moved if you can answer some questions above or give me some suggestions to me? If you come to Beijing, please remember to contact with me.
Thanks a lot!
                                                             A loser from Beijing
Attachments:
DriveFunc(cpp).txt ‏4 KB
DriveFunc(h).txt ‏21 KB

Good Morning Sir,
Can you tell me, what all changes you have done in PLL.vi to run in fpga 7831R? Did your problem got sorted out?

PXI-6509 Error occurred at Reset Device

Greetings Everyone,
     I recently had three (3) PXI-6509's fail in one of my Test Stations. I tried to reset them in MAX and received the following message: "The device reset has failed. The error report from the device driver is as follows: Error -224903 occurred at Reset Device.". I also received "Error -50152". After that while I had the stores list up of all installed boards, the three (3) PXI-6509's removed themselves from the list.  I'm wondering what these error codes are telling me.  The pop up error dialogue box stated that the "Possible Reason(s): Internal Software Error occurred in Static_Digital_software". I'm also curious as to what this is relating to. I replaced all three (3) board from a NEW chassis that I'm bringing up for use and everything thing is fine. I tried plugging these failed boards into my other chassis and the computer will not even boot up. Thank you in advance for any information that you provide that will help me in understanding what may have caused this to happen. The system was working fine up to lunch time and after lunch is when the problems started.
Regards,
Scott
Solved!
Go to Solution.

Greetings Nick,
Here is the course of events that led up to the problem being described.
While testing UUT’s (Company Product): (PXI-1044 with PXI-8101(XP), GPIB Controller and various PXI cards installed)
Before Lunch everything was working well. It was after lunch that the following events took place.
a)     Test Sequence hung up during External Power Supply ramp up in which the D-I/O are used to switch relays inside the ITA (Interface Test Adaptor) to connect the DMM to the Power Supply that is in use at the particular time in the test sequence. This has happened a couple times before, but NO error ever happened and just re-booting the system cleared it.
b)     The next thing that was performed was shutting down TestStand and Labview.
c)     The next thing that was performed was executing “MAX”.
d)    Once in “MAX”, I normally try to RESET all of the PXI cards, which is usually successful, but not in this case. The error pop up came up with the two (2) different error codes (-224903 and -50152). Please explain what the “Static-Digital Software is?
e)     I shutdown “MAX” and Re-Booted the system.
f)      After Re-Boot completed, I executed “MAX” once again and clicked My System, Devices and Interfaces and PXI-1044 “Chassis 1”.
g)     I tried to reset the NI PXI-6509 “PXI1Slot7” and received the pop-up error as described.
h)    Upon clicking OK. The PXI1Slot7 and PXI1Slot8 removed themselves from the stores list of cards installed and the icon next to NI PXI-6509 “PXI1Slot9” changed from a little green board icon to a white board icon with a little red ‘x’ inside it.
i)      Next, I removed all three (3) PXI-6509 from a NEW chassis in a NEW TestStand that I planned to bring on line in a couple of weeks. I placed these boards into the TestStand that is failing and everything is working well once again. I ran some diagnostics and everything checks out OK.
j)      Next, I took the failing boards and placed them into the NEW chassis and the computer wouldn’t even boot up.
k)    Next I removed two (2) (PXI1Slot7 and PXI1Slot8) of the boards and tried to boot the computer and the computer booted up.
l)      I proceeded to execute “MAX” and check the stores list only to find that the board (PXI1Slot9) was not even in the category of the PXI-1044 Chassis1 but outside it and it also had the white icon with a little red ‘x’. It also affected the PXI-2575 in PXI1Slot10, which had a white icon and little red ‘x’. I removed the board from PXI1Slot9 and re-booted the system and PXI1Slot10 recovered with the normal green icon that is usually next to it.
What I need to understand is what “Static-Digital software” is and what the errors are telling me. The fact that three (3) NEW board installed into the chassis and function 100% tells me that there is something wrong with the three (3) boards that I removed from the chassis and that nothing else seems to be wrong with the chassis.
The fact that installing the three (3) boards into a NEW chassis and the computer not booting is something of concern. I’m trying to understand what could have caused this to happen in the first place so I can be prevented in the future.
Regards,
Scott

High attenuation on short line

I'm getting what seems to be quite a high attenuation on what should be quite a short line, router stats below.
Hub is connected to the socket after the master but it makes little difference when connected to the test socket. I've tried the quiet line test and there's a little bit of noise, more so after the BB was activated
I'd estimate I'm no more than 1KM from the exchange (I can see it out of my window!)
What do you guys think? Worth investigating or not?
ADSL Line Status
Connection Information
Line state:
Connected
Connection time:
13 days, 04:40:27
Downstream:
9.368 Mbps
Upstream:
1.078 Mbps
ADSL Settings
VPI/VCI:
0/38
Type:
PPPoA
Modulation:
G.992.5 Annex A
Latency type:
Fast
Noise margin (Down/Up):
5.7 dB / 6.5 dB
Line attenuation (Down/Up):
35.5 dB / 20.1 dB
Output power (Down/Up):
20.5 dBm / 11.9 dBm
FEC Events (Down/Up):
0 / 0
CRC Events (Down/Up):
62774 / 134
Loss of Framing (Local/Remote):
0 / 0
Loss of Signal (Local/Remote):
0 / 0
Loss of Power (Local/Remote):
0 / 0
HEC Events (Down/Up):
249038 / 82
Error Seconds (Local/Remote):
51663 / 62
Hide details

PowermanC3 wrote:
That reports almost 4KM, which is probably quite a bit out. Could it indicate a bad connection somewhere maybe?
Possibly it could however, have you tried to replace your Microfilters?
When I had the problem with my connection (here), the line noise was terrible and I could clearly hear the modem syncing when connecting. Had researched it and found out it could be caused by a HR (High Resistance) fault. 1 month later and having a new lead-in installed, the line was fixed.
Obviously it probably isn't the same scenario but one way to find out is; Does your connection disconnect a lot? I can see your connection has a high uptime so I'm guessing it probably doesn't.
One way I found to diagnose a HR fault by myself was to leave the modem disconnected overnight and in the morning before turning on the modem again, listen for any noise on the line. In my case the Noise seemed to disappear mostly after leaving the modem off for a period of time, despite being diagnosed as a very bad HR fault in the buried Tee which later which turned out to be correct.
The DSL and Phone Signals are on different frequencies and therefore you shouldn't be able to hear the DSL signal on the phone. It means somewhere the DSL signals are leaking into the phone which could be the microfilter, Line Card or a HR fault. Could also be caused by a dodgy phone or Wireless phone.
Any noise on the line as John said shouldn't happen.
Microfilters are the best place to start off with first though if you haven't tried replacing it.
Like this post? Give it a Star . If this post answers your question, please Mark it as the Accepted Solution.

Can anyone help? High noise margin and low sync sp...

Hi all,
just registered on the forum so this is my first post. Hopefully someone out there can help.
I transferred my broadband to BT from Sky. With Sky my sync speed was around 4000kbps and download of about 3500kbps. I had a Netgear router with Sky but for some reason every day or so my sync speed dropped to 2500kbps and download down to 1800kbps. I had to reboot the router to get the speeds back up again, very frustrating.
I got BT broadband on 20/1/2010, set everything up and also fitted an I-plate. I noticed that line attenuation was 46db, this was previously 50.5 with sky and prior to I plate. The home hub sync was at 7200kbps at the start which i was very pleased with. I know this DLM thing is active for the first 10 days or so and speedtests during this time are not exactly accurate but still I was happy. after 3 days i did a speed test and got download of 5800kbps, chuffed to bits!
But, after 2 days at that speed the sync dropped to 2176kbps, gutted. I have only rebooted the router 3 times since the service started and each time the sync goes back to 7000kbps ish but drops again a day later. The thing I dont understand is the noise margin. Its currently at 24.5db, isnt that awfully high? Why is this? when I reboot it drops to 8-9db ish but then goes up again with the speed dropping.
currently connected to test socket, no other telephone equipment connected to any extensions
Can anyone please help/advise whats going on or how to rectify it? I'm wondering if theres a line fault somewhere.
And with attenuation at 46db I would have thought the speed could well be much higher than 2200kbps.
I'll stop babbling now,
Thanks

whitesp wrote:
Thanks for your reply Somerled,
ok so something is causing noise at a particular time, i had wondered about the quality of the home wiring, there are 4 extension sockets in the property, but again i am currently only connected to the test socket.
I dont have the old netgear router unfortunately so can't follow up on the suggestion you made.
God this is gonna be a nighmare to track down, although come to think of it I do have a dimmer on quite close to where the master socket is.
Can we say for sure that there definitely IS a source of noise/interference??
Many thanks
SOMETHING is forcing a resync, and at a low speed. The only thing that would cause that is a prolonged burst of noise.This is known to BT technicians as "REIN" (Repetitive Electrical Impulsive Noise). No point trying to get BT to investigate at this stage though, as it sounds very intermittent.
The way to spot radio interference noise is to use a suitable receiver - and the most convenient is a portable medium wave transistor radio. Tune to a quiet spot at the lowest end of the scale, and turn up the volume. All you'll hear is white noise and the occasional quiet crackle. A burst of noise strong enough to affect the DSL signal will be unmistakeable - a LOUD crackling/buzzing/rasping noise. If that coincides with a resync, you've found it. You then have to figure out what electrical device caused the noise.....
Another possible source of DSL noise problems is less obvious - noise caused by a line fault. This causes an unwanted mixing of the phone and DSL signal in a way that can't be corrected by the filters. This will have much the same effect as external interference noise.
Check this : does the router resync when the phone rings, or when the phone is in use ? If it does, then we're on to something - a fault known as an "HR" (High Resistance). If that doesn't happen, then we are back to external radio interference as the cause.
I suppose the HV lines you mention might have some effect, but it's a bit of a long shot. I'd expect noise from them would be a bit more constant, and would cause problems all the time, rather than intermittently.

Please help, noisy phone line think its a high res...

HI,
Just moved in and phone line / bt broadband was activated a week ago. Phone master socket is OpenReach branded.
I have the BT supplied broadband filter fitted directly to the test socket (just the adsl router and a single phone connected).
Using the 17070 quiet line test , i have varying volumes on hissing and noise on the phone. This varies between loud and intrusive (difficult to hear callers) to fairly quiet. This seemed to be better during the cold weather over last weekend, but is worse again this morning.
I can also hear adsl connection noise when the router was connecting, depsite being through the adsl filters. This lead me to find threads related to High resistance faults whcih I think may apply to me.
BT online fault test shows no fault found.
Adsl Stats:
I was supplied with a home hub 3A
Connection Information
Line state: Connected
Connection time: 0 days, 21:29:11
Downstream: 3.625 Mbps
Upstream: 448 Kbps
ADSL Settings
VPI/VCI: 0/38
Type: PPPoA
Modulation: G.992.1 Annex A
Latency type: Interleaved
Noise margin (Down/Up): 10.6 dB / 15.0 dB
Line attenuation (Down/Up): 32.2 dB / 16.0 dB
Output power (Down/Up): 19.9 dBm / 12.4 dBm
FEC Events (Down/Up): 2941 / 325
CRC Events (Down/Up): 12 / 45
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
HEC Events (Down/Up): 79 / 30
Error Seconds (Local/Remote): 8 / 22
1. Product name: BT Home Hub
2. Serial number:
3. Firmware version: Software version 4.7.5.1.83.8.57.1.3 (Type A) Last updated Unknown
4. Board version: BT Home Hub 3.0A
5. ADSL uptime: 0 days, 21:31:21
6. Bandwidth: 448 / 3712
7. Data sent/received: 0.3 / 2.7
8. Broadband username: [email protected]
9. BT FON: Yes
10. Wireless network/SSID: BTHub3-KC3K
11. Wireless connections: Enabled, (802.11 b/g/n (Recommended)) 20 MHz
12. Wireless security: WPA and WPA2
13. Wireless channel: Automatic / 1
14. Firewall: Default
15. MAC Address:
16. VPI/VCI: 0 / 38
17. Line profile: Interleaved
18. Software variant: -
19. Boot loader: -
The home hub doesn't seem too good at keeping the sync, speed drops regularly and it maintains a high SNR.
My previous router was a Thomson Speedtouch 780, which provides a higher sync and much better stability. Presumably this is due to the broadcom chipset (would a home hub 3b also be better?)
Speedtouch stats from this morning:
speedtouch 4/12/12 08:45
DSL Connection
Link Information
Uptime: 1 day, 10:39:46
Modulation: G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]: 448 / 5.120
Data Transferred (Sent/Received) [MB/MB]: 24,94 / 119,27
Output Power (Up/Down) [dBm]: 12,0 / 19,5
Line Attenuation (Up/Down) [dB]: 15,5 / 31,0
SN Margin (Up/Down) [dB]: 19,0 / 9,0
Vendor ID (Local/Remote): TMMB / TSTC
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 0 / 0
FEC Errors (Up/Down): 0 / 158.090
CRC Errors (Up/Down): 0 / 68
HEC Errors (Up/Down): 0 / 62
speedtouch 04/12/12 09:30
DSL Connection
Link Information
Uptime: 1 day, 11:25:26
Modulation: G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]: 448 / 5.120
Data Transferred (Sent/Received) [MB/MB]: 28,90 / 129,91
Output Power (Up/Down) [dBm]: 12,0 / 19,5
Line Attenuation (Up/Down) [dB]: 15,5 / 31,0
SN Margin (Up/Down) [dB]: 19,0 / 4,5
Vendor ID (Local/Remote): TMMB / TSTC
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 0 / 0
FEC Errors (Up/Down): 0 / 171.051
CRC Errors (Up/Down): 0 / 68
HEC Errors (Up/Down): 0 / 62
As your can see theres a wide range in the SNR figures, although the speedtouch is much better at holding the sync and not dropping the speed.
Given the line attenuation at 31db, I would have expected a higher sync rate. The estimated line length of ~2.2km from kitz.co.uk seems to be about right.
Any advice appreciated, including how to report this fault to the right people.
Thanks
Jon

I'm suspecting that I will be getting billed for the last engineer visit ( as he couldn't find a fault and therefore said it must be my equipment). I can't afford to pay one fee let alone 2 if I report it again with the same result.
However since the visit, the occurrences of the intermittent noise on the line have been fewer and further between. This morning however, after listening to a 1571 message I heard more noise so I did a quiet line test to see. Initially the line was quiet, but then I heard some quit noise and then a ringing sound (like when you dial a number and it rings remotely) as if I had made a call. The "BT Quiet line message" cut in but I could still here the ringing underneath. I waited to see if I would be able to hear if someone answered but the ringing stopped after a while and I couldn't here a voice so I don't know if they answered or it rung off.
Is it possible my line is picking up the ring tone from another line?
Also, when the engineer arrived he initially said his test had shown a fault and that water must have got in somewhere. However when he removed my filter/phone/router from the test socket, his tests then showed no fault. Is it possible the fault only shows up when the adsl is active. Back when the line was first active I could the router negotiating (even thorough 2 filters) although this doesn't happen now.
Moving on to the adsl side of things, Currently my stats are:
DSL Connection
Link Information
Uptime: 0 days, 11:48:54
Modulation: G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]: 448 / 5.440
Data Transferred (Sent/Received) [MB/MB]: 9,61 / 39,04
Output Power (Up/Down) [dBm]: 12,0 / 19,5
Line Attenuation (Up/Down) [dB]: 15,5 / 31,0
SN Margin (Up/Down) [dB]: 20,0 / 5,0
Vendor ID (Local/Remote): TMMB / TSTC
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 0 / 0
FEC Errors (Up/Down): 0 / 1.384
CRC Errors (Up/Down): 0 / 0
HEC Errors (Up/Down): 0 / 0
Interleaved.
With the BT Home hub (3a) the connection would drop peridocally, so I'm using my Thomson 780wl which hold the connection better and also shows less FEC errors than the HH.
I think the connection speed and the interlacing are poor given the line attenuation. The line length is about 2 - 2.5km, underground from the village to the exchange, overground to the house. No cabinets directly connected to exchange.
I've been monitoring signal to noise ratio and have noticed something odd:
This happens every day, in the same pattern. Its not interference from any internal wiring or appliances or heating etc. I understand that noise changes over time but this is a 5+ DB drop is this normal?
Any advice?

Multichannel stream to disk high speed digitizer problem

Hi,
I'm trying to write a code for managing a PXI-5105 high speed digitizer as a multichannel data streamer to disk.
I found the code example on niscope folder (version 3.0) for a single channel datastreaming that works fine. I tried to modify this code,
according to directions included into the code for multichannel acquisition, but it fails. I wrote to NI support and they confirm that my code has to work.
For clarifying better my question, I include my code.
I'm a quite new labview user, I know that my code is not easy to read, but I hope that someone has already encountered my problem and may help me.
Best regards
Paolo
Attachments:
niScope EX Stream to Disk_Paolo_version.vi ‏86 KB

Hi Matthieu,
thanks for your attention to my problem.
The program runs, but it dispays only the first acquisition (first loop), and after there are no data acquired.
Using the single channel mode it works fine, you see a continuous acquisition on display and on disk.
I'm suspecting that there is a problem in the loop where I acquire fresh data (Using the lamp I haven't any data from the Niscope I-16 multichannel block, except for the first run where I get the first data).
I hope this clarify better the situation.
Best regards
Paolo

Pxi 2575 high resistance

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