Data Acquisition Frequently Asked Questions
Here are some FAQ's our visitors has asked us about Data Acquisition.
Q: What is the slowest sampling rate I can use with your software?
A: The DOS DacqEditors will sample as low as one sample per 55 ms. The Visual Basic programs or C programs will take samples at low as you want. The example code shows how to run at 1 sample per 10 seconds with a record of about 28 hours maximum with the default file size.
Q: Does your product work with an xyz laptop and Windows 95?
A:
Yes, all of our hardware works with Windows 95. We have tens of thousands units of our products in the field with no reports of any problems with laptops - except the ones that have special "green PC" power management software. With those laptops and Window 3.x you have to tell the power manager to not time out and shut down the port. With Windows 95 it is normally smart enough to know the port is being used and keeps power on.
For those laptops and palmtops that have very low power serial ports see the AdcDongle 12A application note 1 or use the DacqPod series which has built-in battery backup.
In any case the product has a 100% satisfaction - 30 day money
guarantee.
Q: We would like to digitize a 100mv DC signal with 0.1mv resolution. Can I use 10X gain in front of your AdcDongle to do this?
A: Yes, you can amplify the signal. The AmpDongles and AmpPods we offer will work for your application. It seems many people would like to have a selectable gain amplifier. So the new products are available with gains of 1, 2, 5, 10, 20, 50, 100X.Q: If your AdcDongle 12A gives 100,000 samples per second with one channel with a Pentium-100 MHz; what will the maximum sample rate be with 4 channels or 8 channels?
A: The maximum sample rate decreases approximately by one divided by the number of channels sampled. Thus the 100 Ksamples/sec goes to about 50 Ks/s with 2 channels, 25 Ks/s with 4 channels, and 12 Ks/s for 8 channels.Q: I want a real-time display of some voltage readings. Do you have software to do that?
A: Yes, we have a Visual Basic program that displays up to eight channels in a bar graph. The maximum display update rate is about 100 samples per second with 486-66 MHz PC.Q: How can I use the PC's parallel port for measuring frequency?
A: The parallel port in even the fastest of PC's Pentium 166 MHZ still can do only about 1 MHz using the CPU 100% of the time. So you'll need external hardware to do the prescaling or counting. Sorry, we offer no counting hardware right now. You might try I/O Tech or Strawberry tree. I think they have parallel port products with prescaling counters.
Keywords: miniature stand-alone data acquisition
Q: I'm looking for a data acquisition system for use in a model aircraft. Size < 5cm x 5cm x 2cm Weight < 100grams. Do you know a company that makes such a device, or maybe a circuit diagram or a kit? The ideal spec would be a minimum of 4 channels, 10Hz sampling, 0-5v inputs with minimum size and weight. Either RF link or an onboard storage would be required, I'd like to store about 500 seconds of data (20,000 samples) for post processing on a PC. I could use my laptop (no ISA slot or PCMCIA I'm afraid) in the field to receive or download the data.
We at SiliconSoft are close to release of a new product that will do what you want.
It is called the SugarCube (tm) because it is a fully contained data logger about the size of a sugarcube. It contains a CMOS RISC microcontrololer, A/D IR I/O, EEPROM, Battery and sensor. The
first version is one channel of 12 bits A/D and later up to 8 channels. We will
put the data sheets on our Web site this month. The units will start at about $50
and use an IrDA type transceiver at about $150 (uses a RS232 interface).
Keywords:Data acquision, laptop serial connector
Q: Can I use the AdcDongle to A/D at least one channel with a DB9 (laptop) serial connector? If so, how? Thanks!
Yes, you can do what you want to do. You just use a DB 9 pin recepticle to DB 25 pin plug adaptor. The AdcDongle has been tested and used with many brands of laptops. If the port is a "standard" RS232 there is enough power (5 V at 5 mA) to power the AdcDongle (4.5 V at 2 mA).
