NI-DAQmx VisualStudio C++ 6 Single point analog output

Specs: NI-DAQmx 7, VisualStudio C++ 6.0, PCI-6722,8channel AO
We have a very simple application: set a voltage (actually 6 channels) and keep it until we want it changed again, perform the change very quickly in response to an image capturing algorithm. So I don't need any waveforms or buffering.
In this forum post http://forums.ni.com/ni/board/message?board.id=231&message.id=3283&query.id=18094 you talk about an AOOnePoint example, but I get an error that the NI-DAQ driver does not support my device.
I may need to use NI-DAQmx, but how? I would like to use something like AO_VWrite(,,), maybe for 6 channels in one call. But I can't find it in NI-DAQmx. It seems I need to setup buffers and frequencies. I have a working sample, but it seems a slow and certainly overkill of this simple application:
// Link with \DAQmx ANSI C Dev\lib\msvc\NIDAQmx.lib
#include "NIDAQmx.h"
double[2] data;
int taskHandleAnalog;
int written;
void Init()
    DAQmxErrChk (DAQmxCreateTask("",&taskHandleAnalog));
    DAQmxErrChk (DAQmxCreateAOVoltageChan(taskHandleAnalog,"Device and Channel Info","",0,10,DAQmx_Val_Volts,NULL));
    DAQmxErrChk (DAQmxCfgSampClkTiming(taskHandleAnalog,"",1000,DAQmx_Val_Rising,DAQmx_Val_ContSamps,NUMBER_OF_AO_SAAMPLES));
    DAQmxErrChk (DAQmxWriteAnalogF64(taskHandleAnalog,NUMBER_OF_AO_SAAMPLES,0,1.0,DAQmx_Val_GroupByChannel,data,&written,NULL));
    DAQmxErrChk (DAQmxStartTask(taskHandleAnalog));
void SetVoltage( double voltage )
    data[0] = voltage;
    data[1] = voltage;
    DAQmxStopTask(taskHandleAnalog);
    DAQmxErrChk (DAQmxWriteAnalogF64(taskHandleAnalog,NUMBER_OF_AO_SAAMPLES,true,10.0,DAQmx_Val_GroupByChannel,data,&written,NULL));

Hi,
It looks like you simply wants to output voltages on the analog output channels, but only wants one update at a time with no waveforms or buffering in DAQmx.
As I'm sure you know there are really just 3 types of measurements. Single Point, Finite, and Continuous. Since you want a single value at a time it's just a Single Point operation.
You can find DAQmx examples for single point operations in this path:
C:\Program Files\National Instruments\NI-DAQ\Examples\DAQmx ANSI C\Analog Out\Generate Voltage\Volt Update
Simply place the DAQmx Write Code within a loop and you will be updating one value at a time, but multiple times when "we want it changed again".
Dennis Morini
Field Sales Engineer
National Instruments Denmark
http://www.ni.com/ask

Similar Messages

Simple single point analog output with NI-DAQmx in VC++ 6.0

Specs: NI-DAQmx 7, VisualStudio C++ 6.0, PCI-6722,8channel AO
We have a very simple application: set a voltage (actually 6 different channels) and keep until we want it changed again, perform the change very quickly in response to an image capturing algorithm. So I don't need any waveforms or buffering.
In this forum post http://forums.ni.com/ni/board/message?board.id=231&message.id=3283&query.id=18094 you talk about an AOOnePoint example, but I get an error that the NI-DAQ driver does not support my device.
I may need to use NI-DAQmx, but how? I have a working sample, but it seems a bit slow and certainly overkill of this simple application:
// Link with \DAQmx ANSI C Dev\lib\msvc\NIDAQmx.lib
#include "NIDAQmx.h"
void SetVoltage( double voltage )
DAQmxErrChk (DAQmxCreateTask("",&taskHandleAnalog));
DAQmxErrChk (DAQmxCreateAOVoltageChan(taskHandleAnalog,sChannel,"",m_MinVoltage,m_MaxVoltage,DAQmx_Val_Volts,NULL));
DAQmxErrChk (DAQmxCfgSampClkTiming(taskHandleAnalog,"",Freq,DAQmx_Val_Rising,DAQmx_Val_ContSamps,NUMBER_OF_AO_SAAMPLES));
DAQmxErrChk (DAQmxWriteAnalogF64(taskHandleAnalog,NUMBER_OF_AO_SAAMPLES,0,1.0,DAQmx_Val_GroupByChannel,data,&written,NULL));
DAQmxErrChk (DAQmxStartTask(taskHandleAnalog));

Sorry about this multi posting, I don't know how to delete it

Single shot analog output: How to pulse this. Probably easy, I'm at a loss.

Hello.
I have a piece of machinery that my system is connected to. Every time it reaches a proximity sensor (It's a reciprocating unit), I need to do a single pulse of 5v out of my analog output. It has to be fast, it has to stop until the sensor is reached again, and it can't stay 'on' for long.
I've attached my VI. I'm using a voltage input via DAQ assistant, routed through some logic to produce a 'true' boolean every time that sensor is reached, and that boolean is connected to a case structure with voltage out tasks created in DAQmx.
My problem is that the machine won't reverse while the case is still true and there's still the 5v being called by the true case on the case structure. It has to pulse, then stop, then be allowed to come back when the proximity sensor is reached again. As it is now, the machine reaches the prox and then the whole system stops, as the 'true' condition on the case structure, and subsequent voltage output, remain high.
I've attached the VI and heirarchy as well.
I've tried a few different things here, as well as just using a DAQ assistant with N samples, but that would just retrigger when the loop repeats anyway.
I'd love to sit and bang my head against this til I get it, but I'm under a time constraint. Help!
Still confused after 8 years.
Solved!
Go to Solution.
Attachments:
using create channel.vi ‏94 KB
logicsub.vi ‏32 KB

Ralph, without knowing the exact DAQ card that you are using, it is difficult to give you the best solution. If you want to continue with the solution that you currently have, try adding a shift register to the outer while loop to track the previous value of the boolean. In this way, we can keep multiple values that are above the threshold from causing multiple pulses. Next add a time delay after the DAQmx Write, then add another DAQmx Write to set the output back to your low value. Remove all code from your "false" case. See attached VIs. Please let us know what model of DAQ card you have as we may be able to do something clever like a retriggerable pulse train if your card can support it.
Charles Chickering
Charles Chickering
Architecture is art with rules.
...and the rules are more like guidelines
Attachments:
using create channel.vi ‏98 KB
logicsub.vi ‏29 KB

Ni-DAQ single-point analog sample latency.

I am maybe in my own little world here in wanting to do software-triggered analog sampling and wanting to do it fast. Having bought a PCI-6014 which is capable of 4 microsecond analog sampling I found a simple AI_Read took 95usec. I was somewhat disappointed. Much reading of FAQs and other's postings here didn't help. I posted my own question and got little help.
Well, having spent days working out such problems as how to access hardware under windows I would just like to throw this to the NI world:
Digital in/out: was 6 usec. now 0.9usec.
Analog in: was 95usec. Now 19 if a channel/gain change is required. 6 usec if not.
To the hardware developers - lets have a cheer. The register-level programming is a bit con
voluted, but that comes with the territory when the triggering, etc, is so flexible.
To the software developers - boo, hiss. Wake up, get your act together. So far as programming the card is concerned I did exactly as described in the "E-Series register-level programming manual". The no-change-to-gain-channel case just does the last, trigger step.
Now, imagine what I could charge if I could make the latest nVidia or ATI video card go 10x faster. I suspect those guys know how to write drivers though.

Hi Michael,
There's no question that efficiencies can be exploited once we start using RLP. Configuring the hardware is definitely quicker using this approach. However, programming specific applications using RLP begins to be a headache once you leave the realm of the simple application.
Using the NI-DAQ driver on the other hand gives me a consistent, intuitive interface over almost all of their hardware products. I am also able to pick up LabVIEW, look at some example code and have an application up and running in less than a couple hours without ever programming data acquisition before. NI-DAQ also has an abstraction layer which offers programming benefits but will invariably add some delay to function calls.
It is also important to note that acquisition times are not lost because of the latency of the configuration calls. You will be able to acquire triggered and continuous data at hardware rates!! The only benefit that is lacking is if you want to start a software call to the card in 6us. But this seems to be a mute point since your software timing is OS dependent anyway. Why push a software call to be 6us when your are not sure when the OS will process your application's code.
The only time having a quick configuration would be a benefit is if you are constantly reconfiguring in a software loop. But then your are still restrained by OS timing so you will never have true deterministic results unless you go to an RT system.
The developers of the NI-DAQ driver have had to make many trade-offs when developing such a comprehensive and flexible driver and accommodating every scenario with every user is an impossibility. This particular instance happens to be one of them.
I would like it to be known though that I have been successful, with the NI-DAQ 7.0 driver, at acquiring continuous pattern input with the PCI-6534 card at 50ns resolutions (20MHz). Obviously, the driver has its benefits!!
Anyway, I appreciate the chance to discuss this type of situation.
Ron
Applications Engineer
National Instruments

Hardware buffered analog output single shot

Using DAQmx and M-Series hardware i'm trying to fire a single shot analog output buffered waveform. I need the output hardware timed. I'm able to output a hardware buffered waveform but can't figure on how to configure it for or stop it after prescribed number of cycle runs.
Thanks in advance.
Solved!
Go to Solution.

Hi,
You have a couple of options. You can set your timing to N
samples and you acquisition will stop when N samples have passed. Or you can
use a counter to control the clock of the analog output and then the counter
can be paused whenever you can. Before
we go and dig into the specific details of the scheme let me suggest a couple
excellent reading materials and let me know if they help. M Series Synchronization
with LabVIEW and NI-DAQmx, Continuous Analog Output
with Pause Trigger and Programmatic Grounding of Output in DAQmx, NI-DAQmx: Retriggerable
Analog Output -- LabVIEW and M Series: Analog Trigger
Source.
Also don’t forget to take a look at simpler examples like: Cont
Gen Voltage Wfm-Int Clk-Pause Trigger.vi
I hope it helps
Jaime Hoffiz
National Instruments
Product Expert
Digital Multimeters and LCR Meters

Why can't we have a single point of contact who de...

Three weeks ago our house was hit by lightning and our broadband connection went on the blitz (a Linnit technical term).
The telephone stopped working. I did an on-line check and the connection registered a fault. The on-line system logged the fault with the teachnical team. So far so good...
I received a call from the tech team advising an engineer was coming out to us, if the fault was with our equipment we would be charged. That's fair. Engineer called. My phones were fine, BUT the BT router was where the fault lay said the engineer. We would need to raise another fault report because he only dealt with telephone AND as he was a subcontractor he would bill for the work... He disconnected the router so the phone would work and left.
I work virtually, which means that I can work from my home, so I need the internet even more than my family want the telephone. I plugged the internet back in so that I could continue to work and called BT again from my mobile. Speaking to a very polite guy in Delhi I was asked to describe my phone socket, unplug the router from the office, carry it downstairs to the kitchen where the main socket is, plug the router in there, reconnect, try again, all sorts of stuff before finally being advised that it was probably just the 'microfilter' and that as they were very inexpensive it might be faster for me to go out and buy one and plug it in myself rather than have another engineer come out to us.
So I did just that. In fact, as the microfilters are less than a fiver, I got two... brought them home and plugged one in... didn't work.
Called Delhi again. Spoke to someone else who was, again, very polite. They tried to get me to unplug and plug things in and out again, but I politely declined this time explaining that now the poor internet connection that we did have was running so slowly I am having to commute in to work over Christmas. He sympathised and told us that he would escalate the issue. That was before Christmas. Since then I received a text on my phone on Christmas Day telling me they couldn't reach me!!!
Today I called again to BEG someone to please come out and fix things for us. We aren't technical. We cannot act as pseudo engineers. We pay BT one bill each quarter for a service. Why on earth can't BT provide me with a single point of contact when I have an issue. And if that point of contact could understand me and explain things to me in words and phrases that I understand that would be perfect!
Last year I cancelled three mobile contracts that we'd had since the early 90's with O2 because they were so unhelpful.
BT aren't the cheapest broadband provider but we've stayed with them out of 20+ years loyalty and the understanding that we had a one-stop-shop. Now, it looks as though I'll be shopping around for another domestic broadband provider for 2012.

Thank you for being so helpful and constructive.
I tried to look at the ASDL settings, john46 but it's asking me for my HomeHub password... the only password I have is for our wireless network and that one doesn't work.
I can't test the phone line right now because I'll have to disconnect the internet and I'm currently working on another computer whilst chatting on this one with you. However I will do that later. I'll also look at the RogerB link you provided.
Truth is, we're pensioners who use the internet but we havent a grain of technical understanding between us. We're old fashioned enough to admit that we just want someone who knows what he's doing to come here and fix it for us. It's already cost us £130 for an engineer to come out from OpenReach to tell us the phone line is OK and it's the router causing the problem. Best case scenario is that another BT engineer who knows about broadband comes out and does it because the last BT person that I spoke to in Delhi did actually confirm that there is a fault on the BT side. I'm getting so frustrated right now I'll probably call out an independant I find in Yellow Pages and get charged an arm and a leg again and I'll then cancel with BT in a fit of pique.

Pl/sql block reading reading table data from single point in time

I am trying to figure out whether several cursors within a PL/SQL block are executed from within a Single Point In Time, and thus do not see any updates to tables made by other processes or procedures running at the same time.
The reason I am asking is since I have a block of code making some data extraction, with some initial Sanity Checks before the code executes. However, if some other procedure would be modifying the data in between, then the Sanity Check is invalid. So I am basically trying to figure out if there is some read consistency within a PL/SQL, preventing updates from other processes to be seen.
Anyone having an idea?.
BR,
Cenk

"Transaction-Level Read Consistency
Oracle also offers the option of enforcing transaction-level read consistency. When a transaction runs in serializable mode, all data accesses reflect the state of the database as of the time the transaction began. *This means that the data seen by all queries within the same transaction is consistent with respect to a single point in time, except that queries made by a serializable transaction do see changes made by the transaction itself*. Transaction-level read consistency produces repeatable reads and does not expose a query to phantoms."
http://www.oracle.com/pls/db102/search?remark=quick_search&word=read+consistency&tab_id=&format=ranked

Using LabVIEW and an E-Series DAQ Card to perform relatively high speed single point acquisition in response to a changing DIO pattern.

I am using the DIO lines on my E-series card to drive an external multiplexer which switches 1 of 8 sets of 3 signals to channels 0,1 and 2 on my DAQ. I need to acquire the 3 single points of data, do a little processing, then update the mux code before acquiring the next 3 points of data and so on. I have been trying to do this using hardware controlled loops but can only achieve a real sampling rate (time between the same set of three signals) of about 200s/s. I am trying to achieve in excess of 800 s/s. Any ideas?.

HI CP,
You are doing pretty good if you are getting 200S/s.
I believe the only way you can get 800 S/s reliably is to go to LV-Real Time. Not for the speed, but for the determinism.
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I am currently active on.. MainStream Preppers
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WAP321 2 SSIDs not both showing Clustered in Single Point Setup

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PS
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My name Eric Moyers. I am an Engineer in the Small Business Support Center.
You do not have a setup issue. Clustering/Single Point Setup is based on the device and not on the SSID's. When looking at the Wireless Neighborhood within the Clustering section, you will only see the first SSID listed regardless of how many SSID's you have configured.
Now as far as the connection are concerned you said that your friends were having a hard time connecting. When they eventually connected were they going to the guest network? When you connect with your laptop, are you connecting to the same SSID or a different one?
Eric Moyers
.:|:.:|:. CISCO | Cisco Presales Technical Support | Wireless Subject Matter Expert
Please rate helpful Posts and Let others know when your Question has been answered.

How can I design Load Balancing for distant Datacenters? without single point of failure

Dear Experts,
We are using the following very old and passive method of redundancy for our cload SaaS but it's time to make it approperiate. Can youplease advise:
Current issues:
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Hi Codlick,
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Hi Godel,
Since this discussion thread is over 3 years old, it would be better to start a new thread with your specific questions to get quicker help.
I did a bit of research on your question, and found this helpful White Paper (http://www.ni.com/white-paper/7727/en/) that discusses the resources used for components in LV FPGA code. For local variables (although it depends on hardware), it looks like it uses Flip-flops and LUTs.
As for using local variables with different clock rates, I found this KnowledgeBase article that might help shed some light on your question - some issues can arise from using them with more than one clock rate (http://digital.ni.com/public.nsf/allkb/C683585460E88508862570D1006B7434)
Hope this helps! Again, if you have follow-up questions, I would definitely recommend creating a new thread
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Securing single point of entry doc-lit web services

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Is a cluster proxy a single-point-of-failure?

Our group is planning on configuring a two machine cluster to host
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          Is a cluster proxy a single-point-of-failure? Is there any way to avoid
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          cluster proxy)?
          Thank you.
          Marko.


We found our entity bean bottlenecks using JProbe Profiler. It's great for
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          problems and EBs may be fine for you.
          If you have a cluster proxy you don't need to use sticky sessions with your
          load balancer. We use sticky sessions at the load-balancer level because we
          don't have a cluster proxy. For our purposes we decided that the minimal
          overhead of hardware ip-sticky session load balancing was more tolerable
          than the overhead of a dog-slow cluster proxy on WebLogic. If you do use the
          proxy then your load balancer can do round-robin or any other algorithm
          amongst all the proxies.
          Marko Milicevic <[email protected]> wrote in message
          news:[email protected]...
          > Sorry Grant. I meant to reply to the newsgroup. I am putting this reply
          > back on the group.
          >
          > Thanks for your observations. I will keep them all in mind.
          > Is there any easy way for me to tell if I am getting acceptable
          performance
          > with our configuration? For example, how do I know if my use of Entity
          > beans is slow? Will I have to do 2 implementations? One implementation
          > using entity beans and anther implementation that replaces all entity use
          > with session beans, then compare the performance?
          >
          > One last question about the cluster proxy. You mentioned that you are
          using
          > Load Director with sticky sessions. We too are planning on using sticky
          > sessions with Central Dispatch. But since the cluster proxy is stateless,
          > does it matter if sticky sessions is used by the load balancer? No matter
          > which cluster proxy the request is directed to (by load balancing) the
          > cluster proxy will in turn redirect the request to the correct machine
          (with
          > the primary session). Is this correct? If I do not have to incur the
          cost
          > of sticky sessions (with the load balancer) I would rather avoid it.
          >
          > Thanks again Grant.
          >
          > Marko.
          > .
          >
          > -----Original Message-----
          > From: Grant Kushida [mailto:[email protected]]
          > Sent: Monday, May 01, 2000 5:16 PM
          > To: Marko Milicevic
          > Subject: RE: Is a cluster proxy a single-point-of-failure?
          >
          >
          > We haven't had too many app server VM crashes, although our web server
          > typically needs to be restarted every day or so due to socket strangeness
          or
          > flat out process hanging. Running 2 app server processes on the same box
          > would help with the VM stuff, but remember to get 2 NICs, because all
          > servers on a cluster need to run on the same port with different IP addrs.
          >
          > We use only stateless session beans and entity beans - we have had a
          number
          > of performance problems with entity beans though so we will be migrating
          > away from them shortly, at least for our configuration-oriented tables.
          > Since each entity (unique row in the database) can only be accessed by one
          > transaction at a time, we ran into many deadlocks. There was also a lot of
          > lock thrashing because of this transaction locking. And of course the
          > performance hit of the naive database synching (read/write for each method
          > call). We're using bean-managed persistence in 4.5.1, so no read-only
          beans
          > for us yet.
          >
          > It's not the servlets that are slower, it's the response time due to the
          > funneling of requests through the ClusterProxy servlet running on a
          WebLogic
          > proxy server. You don't have that configuration so you don't really need
          to
          > worry. Although i have heard about performance issues with the cluster
          proxy
          > on IIS/netscape, we found performance to be just fine with the Netscape
          > proxy.
          >
          > We're currently using no session persistence. I have a philosophical issue
          > with going to vendor-specific servlet extensions that tie us to WebLogic.
          We
          > do the session-sticky load balancing with a Cisco localdirector, meanwhile
          > we are investigating alternative servlet engines (Apache/JRun being the
          > frontrunner). We might set up Apache as our proxy server running the
          > Apache-WL proxy plugin once we migrate up to 5.1, though.
          >
          > > -----Original Message-----
          > > From: Marko Milicevic [mailto:[email protected]]
          > > Sent: Monday, May 01, 2000 1:08 PM
          > > To: Grant Kushida
          > > Subject: Re: Is a cluster proxy a single-point-of-failure?
          > >
          > >
          > > Thanks for the info Grant.
          > >
          > > That is good news. I was worried that the proxy maintained
          > > state, but since
          > > it is all in the cookie, then I guess we are ok.
          > >
          > > As for the app server, you are right. It is a single point
          > > of failure, but
          > > the machine is a beast (HP/9000 N-class) with hardware
          > > redundancy up the
          > > yin-yang. We were unsure how much benefit we would get if we
          > > clustered
          > > beans. There seems to be a lot of overhead associated with
          > > clustered entity
          > > beans since every bean read includes a synch with the
          > > database, and there is
          > > no fail over support. Stateful session beans are not load
          > > balanced and do
          > > not support fail over. There seems to be real benefit for
          > > only stateless
          > > beans and read-only entities. Neither of which we have many
          > > of. We felt
          > > that we would probably get better performance by locating all
          > > of our beans
          > > on the same box as the data source. We are considering creating a two
          > > instance cluster within the single app server box to protect
          > > against a VM
          > > crash. What do you think? Do you recommend a different
          > > configuration?
          > >
          > > Thanks for the servlet performance tip. So you are saying
          > > that running
          > > servlets without clustering is 6-7x faster than with
          > > clustering? Are you
          > > using in-memory state replication for the session? Is this
          > > performance
          > > behavior under 4.5, 5.1, or both? We are planning on
          > > implementing under
          > > 5.1.
          > >
          > > Thanks again Grant.
          > >
          > > Marko.
          > > .
          >
          >
          > Grant Kushida <[email protected]> wrote in message
          > news:[email protected]...
          > > Seems like you'll be OK as far as session clustering goes. The Cluster
          > > proxies running on your IIS servers are pretty dumb - they just analyze
          > the
          > > cookie and determine the primary/secondary IP addresses of the WebLogic
          > web
          > > servers that hold the session data for that request. If one goes down
          the
          > > other is perfectly capable of analyzing the cookie too. As long as one
          > proxy
          > > and one of your two clustered WL web servers survives your users will
          have
          > > intact sessions.
          > >
          > > You do, however, have a single point of failure at the app server level,
          > and
          > > at the database server level, compounded by the fact that both are on a
          > > single machine.
          > >
          > > Don't use WebLogic to run the cluster servlet. It's performance is
          > > terrible - we experienced a 6-7x performance degredation, and WL support
          > had
          > > no idea why. They wanted us to run a version of ClusterServlet with
          > timing
          > > code in it so that we could help them debug their code. I don't think
          so.
          > >
          > >
          > > Marko Milicevic <[email protected]> wrote in message
          > > news:[email protected]...
          > > > Our group is planning on configuring a two machine cluster to host
          > > > servlets/jsp's and a single backend app server to host all EJBs and a
          > > > database.
          > > >
          > > > IIS is going to be configured on each of the two cluster machines with
          a
          > > > cluster plugin. IIS is being used to optimize performance of static
          > HTTP
          > > > requests. All servlet/jsp request would be forwarded to the Weblogic
          > > > cluster. Resonate's Central Dispatch is also going to be installed on
          > the
          > > > two cluster machines. Central Dispatch is being used to provide HTTP
          > > > request load-balancing and to provide failover in case one of the IIS
          > > > servers fails (because the IIS process fails or the cluster machine
          it's
          > > on
          > > > fails).
          > > >
          > > > Will this configuration work? I'm most concerned about the failover
          of
          > > the
          > > > IIS cluster proxy. If one of the proxies is managing a sticky session
          > > (X),
          > > > what happens when the machine (the proxy is on) dies and we failover
          to
          > > the
          > > > other proxy? Is that proxy going to have any awareness of session X?
          > > > Probably not. The new proxy is probably going to believe this request
          > is
          > > > new and forward the request to a machine which may not host the
          existing
          > > > primary session. I believe this is an error?
          > > >
          > > > Is a cluster proxy a single-point-of-failure? Is there any way to
          avoid
          > > > this? Does the same problem exist if you use Weblogic's HTTP server
          (as
          > > the
          > > > cluster proxy)?
          > > >
          > > > Thank you.
          > > >
          > > > Marko.
          > > > .
          > > >
          > > >
          > > >
          > > >
          > > >
          > > >
          > >
          > >
          >
          >

Administrative Server - Single Point of Failure?

From my understanding, all managed servers in a cluster get their
          configuration by contacting the administrative server in the cluster.
          So i assume in the following scenario, the administrative server
          could be a single point of failure.
          Scenrario:
          1. The machine, on which the administrative server was running got a
          hardware defect.
          2. due to some bad coding one of the managed servers on another machine
          crashed.
          3. a small script tries to restart the previously failed server from step 2.
          i assume, that step 3. is not possible, because there is no backup
          administrative server
          in the whole cluster. so the script will fail, wen trying to start the
          crashed managed server
          again.
          did i understand this right? do you have some suggestions, how to avoid this
          situation?
          what does BEA recommend to their enterprise customers?
          best regards
          Thomas


Hi Thomas,
          There is no reason why you couldnt keep a backup administration server
          that is NOT running available. So that if the primary administration server
          went down, you could launch a secondary server with the same administration
          information and the managed server could retrieve the required information
          from the backup administration server.
          regards,
          -Rob
          Robert Castaneda [email protected]
          CustomWare http://www.customware.com
          "Thomas E. Wieger" <[email protected]> wrote in message
          news:[email protected]...
          > From my understanding, all managed servers in a cluster get their
          > configuration by contacting the administrative server in the cluster.
          > So i assume in the following scenario, the administrative server
          > could be a single point of failure.
          >
          > Scenrario:
          > 1. The machine, on which the administrative server was running got a
          > hardware defect.
          > 2. due to some bad coding one of the managed servers on another machine
          > crashed.
          > 3. a small script tries to restart the previously failed server from step
          2.
          >
          > i assume, that step 3. is not possible, because there is no backup
          > administrative server
          > in the whole cluster. so the script will fail, wen trying to start the
          > crashed managed server
          > again.
          >
          > did i understand this right? do you have some suggestions, how to avoid
          this
          > situation?
          > what does BEA recommend to their enterprise customers?
          >
          > best regards
          >
          > Thomas
          >
          >
          >

"Read Single Point" Keithley 2400 Problems

Hello!
I am recentely having some problems with the "Read Single Point Measurements" function in Labview 2012. I have already sucessfully used my Keithley 2400 in other programs to sweep the voltage, but now I am trying to use it also to read the current across my sample.
I wrote a very simple program, which resemble the one you can find among Labview examples (see 1st attachment). The only differences are a sweep-subVI and a "for" cycle. My problem occurs at the "Read" Keithley function. On the Keithley's screen I have the following errors:
- 113 : undefined header;
- 230: data corrupt or stale;
- 420: query unterminated.
While in the Block diagram, when the system gets to the "read" function, the error -1074000000 shows up.
I have found a lot of posts on this topic, but unfortunately I could not find the any solution for me. I also tried the 2nd attached program, to check the comunication to the instrument, but errors still occur. In "Measurements and Automatic", it says that the instrument is working properly.
Do you have any ideas?
Thanks
Attachments:
Keithley 24XX Sweep and Acquire Measurements.vi ‏26 KB
Basic Serial Write and Read (1).vi ‏26 KB

The following video demonstrates how to check the firmware revision: http://www.keithley.nl/centralized_display?mn=2400&assetid=55934.
In order to update the firmware you will be need to download a flash program and the firmware file. gAfter obtaining the Flash program and the Firmware file from Keithley Application support staff, unzip the three files in a folder of your choice and run the "setup.exe" program. Follow the instructions to install the program. When the installation is complete, launch the program from your Windows Start menu under Programs/Keithley Instruments. The Application support staff will also provide the file for the latest firmware revision. Put that file in a folder where you can find it and then run the Flash Wizard32 program. The program will autodetect the instrument and request to specify the firmware file.
This link contains the flash program: http://www.keithley.com/base_download?dassetid=52609
See attactment for the firmware revision.
Attachments:
2400c30.zip ‏358 KB

NI-DAQmx VisualStud​io C++ 6 Single point analog output

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