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This page explains how to set up pulsing as well as other hints and tips to consider.
Pulse types: (need lots of editing)
If you specify a pause then the current will be 0. The current value specified in a Pause pulse definition is ignored.
So if you want it to alternate between -60mA and -360mA you would specify the pulse definition as follows:
Pulse1, Discharge, 60mA, 40mS
Pulse2, Discharge, 360mA. 960mS
Only specify a pause if you want the current to be 0 during that portion.
Global pulse enabling
It will show up in the status bar on bottom of screen: Pulse: “Pulses – Off”
You can do a global shut off: Analyzer/Options/Advanced/Apply Pulses = Off.
Asynchronous Sampling:
The sampling of data (V,I,Time) occurs an evenly spaced intervals. This interval is determined by the setting used for Sample Rate: See Analyzer/Options/Data Collection
Sync Samples to Pulse:
When trying to collect data on infrequent pulses this option can be used to guarantee that a sample (V,I,Time) will be collected on every pulse. For example, if you have a short duration pulse in a longer pulse train, then this option will ensure that a sample is taken during this short pulse. This forced sample is taken at the very end of the pulse just before it transitions to the new pulse.
If the objective is to collect voltage data during a short duration pulse then this option ensures that the analyzer will sample the data. In some cases this feature can distort the mAH accumulator readings because a disproportionate number of samples will be taken during the short duration pulse.
Dear Mr S.
The MC and LC analyzers feature a synchronous pulse sampling option. This way you can get a sample with each pulse regardless of the normal sampling rate or pulse duration.
This is good for infrequent pulses of short duration like your example. The user just needs to select this option in software and set the Collection interval=0 so that all data is collected and saved.
This is nice because you don’t need to collect a lot of data, but yet still get at least 1 sample on every infrequent pulse.
In answer to the specific questions:
1. You can probably get about 50 or 60 per second depending on the speed of your computer, but again with the synchronous pulse sampling option you do not need to collect a lot of data to get a sample during the pulse.
2. The log is a csv text file that you can easily import into a spreadsheet program
3. The graph zoom interval is similar to BA400WIN. You can adjust the scale factor in the options and then zoom in out with the arrow buttons.
4. You would want to use the synchronous pulse sampling option. I tested your scenario down to a 5 mSec pulse and it worked nicely. Every pulse showed up in the data, even using a normal 4 samples/sec rate.
mAH accumulator:
The mAH accumulator is processed once per second. If the pulse is very small, relative the the total period, then the mAH accumulator may not advance in a steady fashion. If there is a large pause interval, relative to the current pulse, then the mAH accumulator will only advance when the pulse is active at the time the accumulator is processed. Over a period of time however, it is accurate, because the probabilities even out over time.
This is also true for a more complex pulse definition that has many parts. The mAH accumulator will register for the pulse in effect when the accumulator is updated, but over time becomes accurate as the probabilities even out.
When using a pulse profile that has a period of exactly 1 sec (or multiples thereof) then the pulse can get synchronized with the mAH accumulator and distort the mAH measurements. This is because the same pulse is always in effect at the time the accumulator is processed.
For example:
– Discharge 50mA for 0.25 seconds
– Pause 0mA for 0.75 seconds
will cause the mAH accumulator to always see either 50mA or 0 mA.
For the above example an alternate pulse profile for 25% duty could be:
– Discharge 50mA for 0.30 seconds
– Pause 0mA for 0.90 seconds
This way the accumulator will see all parts of the pulse and will be accurate over time.
Time Limits: (Needs updating)
The maximum number of seconds that can be specified for a pulse duration is 6891 sec (1.9 hours) The minimum resolution that can be specified is 0.0000016 sec (1.6uSec)
You could use multiple consecutive pause pulses but you still would not reach 20 hours
For longer durations you should use a program. In a program the maximum duration is 651 days.
So for your example you could have a 3 step program.
Step 1: Pause for 5 min
Step 2: Discharge for 5 min
Step 3: Pause for 1200 min (20 hours)
Data Collection Strategies (needs editing)
The samples readings are timed and are not synchronized to the pulse. So to be able to capture a 300ms pulse you should use a Sample Rate of at least 4 samples/sec. ie a sample reading every 250ms. Now this will just ensure that the analyzer has at least 1 reading during the pulse. It still needs to pass this data to the computer and ultimately your log file before you can see it.
The analyzer can store 15 samples before they get overwritten. So you need to poll the data often enough to get the reading that occurs during the pulse up to the computer. At a sample rate of 4/sec the analyzer can store 3.75 seconds of data. So a Poll Interval of 1 sec should be often enough to ensure that all the data collected by the analyzer is passed to the computer (ie no overflows). You didn’t specify what Poll Interval you are using but I assume it is every 1 second.
At this point the pulse data should have been uploaded to the computer. BA400WIN does not save all the data that passes from the analyzer to the software. You control this with the Collection Interval. So if you really want to see all of the pulses on the BA400WIN graphs (& log file) you would need to have a maximum collection interval of 0.25sec to be sure to retain the sample that occurred during the infrequent pulse. I don’t know what Collection Interval you are using. Note that you can enter a value in the Collection Interval box. You are not limited to the displayed choices. Note that when you collect a lot of data it can start to overwhelm the computer. If the computer gets overwhelmed things can get bogged down and you might see problems. If this is an issue reduce the graphs update interval. It is the graph update processing that will grind things to a crawl. With large data files it takes a long time for the graph to reprocess all the data to update the graph. Set the Graph Update interval=1/min or even 0 (off). You can always turn it on again later to view the graph. If these session run a long time the data files will get huge so best to keep the graph off.
Now at this point you should be able to find the pulses in the data using the graph. However you still do not have the data in the log file. You will need to have a data log interval fast enough to write data so you can see all the small duration pulses. Again a Data Log Interval=0.25 sec should capture the pulses. Again you will be writing a lot of data to the computer. The files will get large and cumbersome so if you really want to see every pulse you are going to have to look at a lot of dead air before you find the pulse.
Remember, just because you don’t have a record of the pulse occurring, does not mean it didn’t happen. It might be strategic to figure out why you need to see every pulse. If you would be happy with seeing just a fraction of the pulses then the files could be a lot smaller.
Calibrating pulses:
For short duration pulses (<100mS) that require high accuracy it may be necessary to calibrate the pulse timing if there are pause intervals in the pulse train. The rise time of the pulse can be affected by things unique to the test situation. Parameters such as: battery voltage, pulse current, pause time, and the pulse current immediately preceding and following the pulse can have some impact on the exact timing of the pulse.
If all the pulses in the pulse train are all similar then there will be negligible effect on the pulse timing. However if there are pauses and the pulse current duration is very small then the error can start to become significant. In this case use a small value series resistor in the circuit and use a scope to monitor and adjust the pulse duration until it is exactly as required.
For longer duration pulses ( >100mS) the response time of the pulse will be negligible and pulse interval calibration is not required.
Typical Setting when pulsing:
– Samle Rate: 4/sec
– Poll Int: 1 sec
– Coll Int: 5 sec
– Reading/Sample: 4
– Data Log Int: 60 sec
– Graph update int: 5 sec
– Apply pulses On: Discharge
– Sync samples to pulses: unchecked
For a pulse profile I used:
– Discharge 20mA for 0.0453 sec
– Pause 0mA for 3.6 sec
