NI 9264 Voltage Drop

Hi all,
I have a CompactRIO with NI 9264 module, connected to this Mass Flow Controller: http://www.omega.com/pptst/FMA2600_FVL2600.html. Acquiring the flowrate from the MFC is not a problem. However, I'm having problem in controlling the MFC using NI 9264 module. Basically, when the module is not connected to anything, I'm reading the correct voltage out from the module - correct means, the same as what the program gives. However, it is connected to the MFC, the voltage drops down to 0.4V and this is regardless of what voltage command that I give. I was told that this may be due to impedance mismatch between the module. Is this true? If yes, can anybody please elaborate further? More importantly, how do I resolve this? Will putting an additional resistor in series or in parallel to the circuit work?
Thanks for your time and advices.
Shazlan

Hi Henrik,
Thank you for taking the time to respond. I've attached the datasheet to my previous reply and I'm attaching the manual in this reply, for other people's reference. We are using FMA-2600 the standard version (no optional selection selected). On wiring, based from our understanding of the explanation, we just need to connect the positive pin of the 9264 to pin 4 of the connector and the COM on 9264 to pin 8 (Ground). Voltage input is being connected to another C-Series module and using the same method (Pin 6 Output signal to positive on the module and Pin 8 ground to COM). Can you please help to clarify what do you mean when you say "250Ohm resistor to ground..."?
I agree that ideally, RS-232 is the way to go. However, the only serial port on the cRIO is connected to another instrument and we do not plan to buy another 232 module.
Thank you again.
Shazlan
Attachments:
FMA-2600 Manual.pdf ‏3913 KB

Similar Messages

Reading Voltage Drops Across Multiple Resistors

HI,
We are creating a PC interfaced IC tester. To do this we need to be able to monitor and record the behavior of the chip in question. The easiest way we have come up with to do this is to place common resistors on the inputs and outputs of these basic devices. By doing this we will be able to read the voltage drop across each resistor, since we know the resistance we can then figure out the current, we measured the voltage and we know all we need to. The problem we are having is reading in multiple channels of data at once. We are using Labview version 7.0 and DAQ PCI-6024E and have our inputs set up in differential mode. We can get one channel to read but when two are connected we have problems with our readings being affected by each other. I have attached the vi file so if anyone can be of any assistance it would be much appreciated. We are beginners here so please be as specific as possible and dumb it down if necessary.
Thanks in advance
Rylon
Attachments:
ICtester.zip ‏214 KB

Hi Rylon-
It sounds like you are seeing ghosting of signals between your channels. KnowledgeBase "How Do I Eliminate Ghosting From My Measurements?" should be helpful in reducing this effect.
KnowledgeBase "Seeing the Same Signal on Several Scanned Channels, Especially when No Signal Is Conn... may also be pertinent if you are leaving the channels you're not testing without connections between testing channels.
Thanks-
Tom W
National Instruments

Random Differential Voltage Drop (DAQ 6008)

While measuring a constant voltage of 5V with the DAQ-6008 I get voltage drops (from 5V to near 0) randomly and for very short periods of time. I've found the same issue even when using different voltage sources. I am attempting to use the voltage on this particular channel as an analog trigger. So, as you can infer, the random voltage drops cause unnecessary triggering. Any Ideas?
Regards

Thank you for your response.
I am including all of the requested information:
1. The LabView vi
2. .txt data output file (open in notepad)
3. A picture of an example setup I am using to test the triggering system (note, this is one of several setups that all have the same triggering issue)
I'm certain the connections are not the problem considering the simplicity of the test circuit as shown in the attached image.
I have my DAQ-6008's ai3 port hooked up to the voltage input (the battery pack as shown in the picture, E.G.). Normally, the ai3 port would be connected to a binary sensor that ouputs either a 5v output or a 0v output depending on the presence of an object. As you can see in the vi, I am attempting to compare each of the incoming ai3 voltages to a value (4.5); if the incoming voltage rises from 0V to above 4.5V, a true signal is outputted and the trigger should activate once by incrementing the wheel count once. The problem presents itself here by incrementing the wheel count randomly even if a constant voltage source remains above the 4.5 threshold value. You can see in the data file that all of the values are 5.208543. Again, this constant voltage is exemplified by the battery pack in the picture. There is no random incrementing if the voltage source remains at 0V.
Attachments:
ME481 DAQ WORK 10.vi ‏110 KB
IMG_20111128_131137.jpg ‏777 KB
test_11-11-28_1300.txt ‏694 KB

Voltage drop problem gd 65 z77

Hello,
I think i have a problem.
Mainboard Msi Z77a GD65, CPU i5 3570K.
Overclocked CPU to 4.5Ghz with a voltage of 1.265v from bios, but in windows it shows me as 1.248v , and whenever i use a stress program for cpu it shows as 1.224v-1.230v . (but at default bios settings 1.235v i never see any vdrops , was stable, and reason i increased the voltage was to avoid the Max Payne 3 black screen)
There is an option at bios called Vdroop offset control , i heard its for cpu idle state. But when i set this to %12,5 , instead it will drop at idle, it drops at load. I think LLC Load Line Calibration option is not on MSI bioses , if exist so i can setup with it. How can i fix this problem pls?
And btw when i use OC genie II button and start the pc, instead pc starting it keeps closing itself repeatedly.
My system :
İ5 3570K
z77a-gd65
Corsair VENGEANCE 8 gb 1866 mhz cl9 (4x2)
Zotac gtx 690
60 gb ocz vertex 3
1.5 tb seagate barracuda
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Bios version 10.5
not : when voltage is 1.235, it drops tp 1.200v at load and drops to 1.216 at idle.

Quote
the core voltage is auto and vdroop %75 Windows startup screen, blue screen.
Voltage 1250 vdroop 100%
Windows went through the processor core voltage when the load drops again
Vdroop is on automatic when voltage drop at least
So you say Vdroop set to 75% on the gd65 was lower than auto vdroop w/ cpuv set to auto? Did you verify this with a multi meter?
That is against the testing that both Bern and I did, might want to set to optimized defaults and update the bios to the newest beta.
<<<z77a-gd65 Beta Bios>>>
Make sure to use the forum flash tool: >>Use the MSI HQ Forum USB flasher<<
Here is an example of how vdroop effected the "auto" Cpuv on my z77a-gd80. I'll try to find Bernhard's that was performed on the gd65 as well.
The test I linked to was using a turbo overclock much like this:
https://forum-en.msi.com/index.php?topic=159647.0
Here are Bernhard's results on the same mobo, but both of these were done with a SB CPU.
(Linked with his permission)
If after the bios update your vdroop behaves differently, I would love your feed back or even a similar test showing the different behavior.

MOVED: voltage drop problem gd 65 z77

This topic has been moved to Overclocking, Undervolting.
https://forum-en.msi.com/index.php?topic=162022.0

Quote
the core voltage is auto and vdroop %75 Windows startup screen, blue screen.
Voltage 1250 vdroop 100%
Windows went through the processor core voltage when the load drops again
Vdroop is on automatic when voltage drop at least
So you say Vdroop set to 75% on the gd65 was lower than auto vdroop w/ cpuv set to auto? Did you verify this with a multi meter?
That is against the testing that both Bern and I did, might want to set to optimized defaults and update the bios to the newest beta.
<<<z77a-gd65 Beta Bios>>>
Make sure to use the forum flash tool: >>Use the MSI HQ Forum USB flasher<<
Here is an example of how vdroop effected the "auto" Cpuv on my z77a-gd80. I'll try to find Bernhard's that was performed on the gd65 as well.
The test I linked to was using a turbo overclock much like this:
https://forum-en.msi.com/index.php?topic=159647.0
Here are Bernhard's results on the same mobo, but both of these were done with a SB CPU.
(Linked with his permission)
If after the bios update your vdroop behaves differently, I would love your feed back or even a similar test showing the different behavior.

About my voltage drops and Vitru Technology

Ok, as far as i know the vdroop can't be disabled in my GD65 motherboard, it's only Auto and +12.....+100 [now it's Auto]
For example if i put in BIOS the voltage 1.23V, back in Windows when it's idle the voltage is 1.23V, but when i stress test the CPU it drops on 1.21V
I guess i have some sort of vdroop that is in my motherboard, and it can't be disabled ?
And for a multiplier OC, i should disable EIST and C1E ?
And regarding Virtu Tech. Why when i enable Virtu in the BIOS, then i click save bios settings, my PC stops and automatically starts 4 times ??

Quote from: CalinTM on 09-January-13, 22:50:26
Ok, as far as i know the vdroop can't be disabled in my GD65 motherboard, it's only Auto and +12.....+100 [now it's Auto]
For example if i put in BIOS the voltage 1.23V, back in Windows when it's idle the voltage is 1.23V, but when i stress test the CPU it drops on 1.21V
I guess i have some sort of vdroop that is in my motherboard, and it can't be disabled ?
And for a multiplier OC, i should disable EIST and C1E ?
And regarding Virtu Tech. Why when i enable Virtu in the BIOS, then i click save bios settings, my PC stops and automatically starts 4 times ??
When I enabled / disabled the IGD with my SB Cpu I had the same behavior on the initial boot. THen it was fine.
No you cannot disabled vdroop, 100% is as close as you can get to none.
If you want EIST & C1E, I would suggest a turbo oc. If you want to do a hard multiplier oc, suggest disabling the power savings features.

MBP late 2010 CPU voltage Drop to 0.8V Runs slow

Hey all,
So recently ihave been using my computer for music production and it has been getting crazy CPU spikes.
I have put this down to my CPU core Voltage sitting at 0.8 V and not being regulated as it usually does
It will work fine one day then just slow down while im working on music.
Rebooting and resetting SMC does nothing.
can anyone help me here??
i know that is supposed to be at around 1.1 V or thats what its at when its working fine.
I have read maybe a dying battery could be the cause, although it happens when its plugged in and on battery
This problem comes and goes and i want to know whats going on
HELP PLEASE!

Just to let all know,
I have Solved the problem for now,
I did edit the Kext to fix the Kernel 200% thing a while ago,
Booted into Safe mode, did a disk a disk verify/repair and it fixed the kext up
Got back into mac OS and its working again.

PCI-6723 voltage output drop observed for 8 channels coninuous updation at 100ks/sec

Hi all,
Iam working on labview 7.1 NIDAQmx7.3 and pci-6723 card.i am generating 8 analog outputs simultaneously,and the voltages and frequency can be changed during fly.The problem is during the run time iam observing some voltage drop of 1mv to 4mv this is really worst for me .out of 8 channels 6 are dc voltages, for these channels also iam sampling at 100ks/sec.is this really a problem.bcos dc voltage needs 1 sample also.if sampling is the problem how can i change individual channel sampling frequency or number of sampples,gothrough the attachment please.
THANKS AND REGARDS
LABVIEW BOY
Attachments:
multipleanalog9.vi ‏154 KB

Here is the modified vi. Hope it works or at least illustates the idea.
Attachments:
multipleanalog9_modified_1.vi ‏140 KB

Why does my FP-1600 take a 24V .5 Amp Power Supply and drop the Voltage to 11V at .5 Amps?

I have a FP-1600 connected to 4 FP-TB-1 bases. 2 FP-AI-100, 1 FP-TC-120, and 1 FP-AO-210 modules. I am powering the FP-1600 with a 24 V .5 A power supply. There are no devices currently connected to any of the modules. The power supply should be supplying 12 W, which should be enough to power the FP-1600 and the 4 modules according to the power requirement calculation in the manual P = 7 W + 1.15*#modules. When I install the third module, the FP-1600 stops communicating. Checking the power supply I see that the voltage drop across the power terminals on the FP-1600 is only 11V and then measuring the current being drawn it is .5 Amps, which is only 5.5 W, not enough to power the devices. When I unhook the power supply and measure the Voltage it is 24 V.
Why is the FP-1600 dropping the Voltage to 11V? Should I just purchase a 12V 2 Amp power supply?
Thanks for any help
Jeremy

Hello jqk,
You got it figured out. The maximum current that can be drawn is .5 which is too small. As the current being drawn approaches the maximum allowable current, the voltage will begin to drop. Eventhough the current you measure is .5A, the fact that the voltage is 11V means that the circuit requires more current to function properly.
As a rule of thumb, you want the maximum current your power supply can deliver to be at least the double of the system's maximum current consumption.

Core voltage stability on 865PE Neo2 PFS

I've just installed one of the new P-series NEO-2 MOBO's. Nice piece of work, although it seems there is still some work left to be done. Definite problems (although not serious) in Core center (althoug other posts indicate this may be indiginous to core center itself..)
More serious though is a reading of the processor core voltage.
I'm using a Celery 2.6, OC'd to 3.25G, FSB 125. Had to raise core voltage to 1.6V to get there, lower voltage led to crashes as low as FSB 104...
Recently, I looked at a scan of the core voltage (provided by Speedfan):
The problem lies in the fact that during disk access and/or high processor load, the core voltage drops as much as 90 mV, bringing it back to its default setting (spikes in graph, longer drop was writing DVD, CPU benchmark has similar result).
If it does this at 1.5V, I can understand the crashes.
I get the impression this board could do MUCH better with more stable voltage regulation.
Anyone seeing similar behaviour in other Neo2-boards? Am I missing a setting?(core-cell may be intervening) It's hard to imagine the PSU can't hack it.. 12V level is rock solid.
System: MSI 865PE Neo2 PFS, Celeron 2.6G @ 3.25G (125 FSB)
1x corsair 3200 512MB @ 333
POV 5600 VIVO
WD800BB 80GB
PSU: HEC 350 VD-PT (3.3V@28A, 5V@33A, 12V@15A)

I'm not worrying. Just a bit surprised we all make a bug fuzz about overclocking, increasing core voltage by 25 mV at a time, and suddenly ignoring it all and "accepting" 70 mV drops if we need processing power...
If the voltage regulator would be more robust, it would be able to maintain the Vcore to (much?) higher power ratings.
This board drops by roughly 70 mV, constituting 3 notches on the voltage setting tab.
I went up to 1.6V, and what I actually get is 1.52.....
To have 1.6 available under all conditions, I'd need to set to 1.7 (yes, I've tried), which is over the top for "normal" overclocking (not to mention considerably higher temperatures).
Anyway, I'd like to know what other boards are doing regarding Vcore stability. Anyone out there with additional data?
Maybe a new target for modifications? (if it's worth it...)

7344 Motion board stop command causing system to drop

I have a hydrolic system(in closed loop mode) controlled by a 7344s analog output.
a value changes depending on the voltage from the 7344:
positive voltage lets water into the system
negative voltage lets water out of the system.
due to the design of the system, water has to be constintly fed into it to hold position.
Now if I call a stop command while holding position(encoder counts are not moving) the voltage drops to zero before going back to its previous value(1-1.5v) only issue is that the system drops until the voltage gets back up.
In contrast, a halt stop is immediate and abrupt. The target position is set to the position of the axis at the moment the VI is executed. On servo axes, full torque is applied to stop the motor(s) as quickly as possible. On stepper axes, the step pulses are immediately ceased.
I am using a halt stop(1) would a decelerate stop(0) be better for this application?

The behavior you are describing sounds like the response of a halt stop when a following error exists in a closed loop stepper. When a halt stop is performed on an axis the following error is cleared and the holding force on the motor is removed. This is a known issure for NI-Motion drivers prior to 7.2, and is fixed in that release. You can download the NI-Motion 7.2 driver here:
NI-Motion Version 7.2 for Windows 2000/XP
http://digital.ni.com/softlib.nsf/websearch/a38d3ad4a8b0f200862570f100758773
S. Arves S.
National Instruments
Applications Engineer

How to measure current and voltage and rpm with daq device

i am measuring current and voltage and am wondering should i use shunt resistors or current sensors hall effect sensors. i have a pci 6221 and a scc-68 breakout box. what specifications or size should the shunt resistor/current sensor be or should i use another device to measure the currrent and voltage. do i need any other safety device between the resistors, current sensors and the scc-68 breakout box when measuring the current and voltage. will the daq card pci 6221 pick up a signal from the resistor. what terminals should the wires from the resistors and current sensors be connected to in the scc-68. i am using a proximity switch to measure rpm of a motor. should the proximity switch be 2 or 3wire connection. should it have an analog or digital connection and is a power supply required to power the proximity switch and should it have an npn or pnp connection

hello,
i was going to use a 20amp 50mv, or a 20amp 100mv current shunt and connect wires directly into the AI input terminals of the scc-68 from the current shunt would these be suitable. would current shunts such as these be suitable to use http://uk.farnell.com/elc/sh10020/shunt-sh10020-20a-100mv-1-class/dp/1319576 or http://uk.farnell.com/datel/3020-01098-0/shunt-50mv-20a/dp/1339338
is it ok to use either a current shunt or should a hall effect sensor be used such as this http://ie.farnell.com/honeywell-s-c/csla2cd/sensor-hall-effect/dp/1082269 . which of them would be more accurate or are both of them fairly accurate.
when i am measuring voltage can i connect two resistors between the positive and negative of the wires going to the battery and connect two wires from either side of the resistor directly into the analog inputs of the scc-68 and measure the 12-15 volts directly would the pci6221 and scc-68 be able to measure the voltage drop across the resistor.
i wanted to measure rpm also does it matter whether the proximity switch has 2 or 3 wires and should it have an analog or digital/frequency output for cponnecting to the scc-68

Can the USB-9211 Thermocouple Input device measure voltages ?

Can the USB-9211 be used to measure voltages ? It is designed for thermocouple measurements and its operating manual states there is a current source between its TC+ and TC- input terminals.
What amount of current is flowing ? Does it depend on the selected thermocouple type ? Can the current level be controlled by sotware ?
One application for me is to measure resistances of 1 ohm or less by measuring the voltage drop across the resistance induced by flowing a current through it. Might the 92111's current source be somehow used for this ?
What is its peak to peak input noise ? Its specs say 1 uV rms.
This is a delta-sigma converter. Is each successive measurement accurate or does some digital filtering have to be account for and thus it takes several readings for a signal change to become accurate ?

The 9211 measures voltages between 0 and 80 mV only. The current source is only use to force a full scale input if an open thermocouple is connected and cannot be controlled by software. The input impedance of each channel between TC- and TC+ is 20M Ohm. However, the current that flows in the amplifier is very small, 50 nA.
The main problem here is the fact that the current source is not controlled by the user. This means that connecting a resistor of 1 Ohm between TC- and TC+ would not just produce a voltage that maybe due to external exitation, but the internal source should also be taken into account. Since the user has control over it, it would be a guess work to try to make sense of any voltage value read in.
its peak to peak input noise is 1 uV rms as indicated in the specs.
So as long as the measurements allow for enough settling time (12S/s), each one is accurate.

Offset problem in simulating current and voltage phase relation of parallel rlc circuit, Is it a bug ?

tested multisim for Parallel RLC Circuit with voltage source as in
http://www.electronics-tutorials.ws/accircuits/parallel-circuit.html
But the current flows through the inductance L has DC component as in the picture attached (the red sine wave). Is it a bug ?, please tell me how to correct it.
Attachments:
phasor.jpg ‏183 KB

Hi there,
As strange as this may sound, this is not a bug. OK, this sounds really funny, but I am totally serious, and I am going to explain why:
In a circuit energy must be conserved.
An inductor is a purely reactive component, that is, it does not dissipate any power.
When simulation starts, Multisim assumes the inductor current to be 0, which may seem reasonable. The voltage across the inductor is also 0 at this point. This is the initial condition.
The voltage across the inductor increases, and thus, the current increases. The current keeps increasing during the first 2 quadrants of the sinusoidal phase output.
The current never decreases until the voltage drop is negative.
But by the time an entire cycle is over, the current is back to 0. This makes sense as energy is conserved and the inductor is not absorbing any energy.
OK. Now look at what happened. During the whole cycle, the current was positive only! The current increased during the first half of the cycle and returned to 0 during the second half. This is because of the fluke of initial conditions! In fact, a good circuit simulator will maintain the DC offset for a long duration. The DC offset may drift because of rounding errors and the like.
This will never be observed in real life as real inductors have winding resistance and other problems.
OK, so, if you would like to see no DC offset, do the following:
Run your simulation
Record the DC offset that you want to eliminate
Stop your simulation
Double click the offending inductor in the Multisim schematic
Click on the Value tab
Check the Initial conditions box under Additional SPICE simulation parameters
Enter the negative of the DC offset that you recorded in step 2 into the box right next to it
Start your simulation. Did your offset go away? Or did it double?
If your offset doubled, take away the sign from the DC offset that you entered in step 7. I bet you know why.
It took me a while to figure this one out. Hope that helps!
Yi
Software Developer
National Instruments - Electronics Workbench Group

When I send a 5v from the DAQ, the voltmeter shows 5V, but when i connect a "normally open valve" from parker to the DAQ, the voltage automatically decreases to .14 V. It seems like it is being grounded. Why is this happening?

We are sending 5v to the DAQ using a voltage generator. We hook this up to a voltmeter and we see 5V. When we connect the voltage generator to a "normally open valve" from parker, the voltmeter shows .14V. It seems that when we connect both wires from the valve to the voltage generator, the wires are acting as a ground. We wish to control the voltage that flows to the valve through Labview. We checked the wires of the valve and they are working fine becuase if we send a constant 5V from the DAQ and grounded it, the voltmeter shows 5V. Does anyone know why the wires are acting as a ground and dropping the voltage to .14V?

nsatpute wrote:
Our DAQ is NI USB 6259. The valve only requires a max of 5V and our DAQ does provide up to 5V. However, after connecting the valve to the DAQ, the voltage drops to almost 0. We are assuming that the wires somehow act as a ground, but we are not sure if this is the case.
The issue here is not how much voltage the valve wants, it is the current the valve needs. The 6259 can only put out 5mA through an analog output. Your valve very likely needs a lot more than that. So you need to add in an amplifier circuit that can supply more current to operate your valve.

NI 9264 Voltage Drop

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