Case Studies
Tester for High-Power Laser Lamp Array
THE PROBLEM
The customer is building a tester for an array of high-power laser lamps. These lamps draw 35,000 Amps of current. The test involves sending a control signal to the laser lamp and measuring the time between the signal and the switching on of the lamp (which is picked up by a photodiode). This time is representative of the quality of the lamp.
The customer currently has a 16-channel system, and would like to explore increasing the number of channels. In the customer's present system, eight CompuScope 512 cards are installed in a GagePC using a PIA720 chassis. The customer wants to increase the number of channels, but with a PIA720 chassis, this customer has already reached the maximum of eight cards in his system.
Below is a representation of the customer's setup (overhead view):
GAGE'S SOLUTION
Let us first calculate how many data points are needed to sample the entire revolution in on-board memory at different rates.
| Number of Points |
= Record Length (in sec) * Sample Rate (in Hz) |
| At 10 MSPS rate, Number of points |
= 83 ms * 10 MHz |
|
= 830 Kilosamples |
| At 25 MSPS rate, Number of points |
= 83 ms * 25 MHz |
|
= 2,075,000 samples |
|
= 1.978 Megasamples |
There are two solutions for this situation:
Option #1:
32 channels with 5 MSPS simultaneous sampling
This option can be represented by the following diagram (overhead view):
In this system, two sets of eight CompuScope cards are installed in a 20-slot ISA backplane GagePC. A special two-level chassis is used, in which the 20-slot backplane is on the upper level, and the drive bays and power supply are housed on the lower level. The special power supply is a combination of a CompuPower 100 and CompuPower 200, ensuring the added power required in this system. The two groups of eight CompuScope cards are internally linked via a custom signal conditioner, to ensure synchronization of the clocks and triggering.
Option #2:
64 channels, with 5 MSPS simultaneous sampling
This option can be represented by the following diagram (overhead view):
Option #2 combines two of the Option #1 systems, except that the second GagePC has no CPU. A Bus Expansion Kit connects the two systems, so that the cards in Chassis #2 behave as though they were on the same bus as the cards in Chassis #1. Again, clock and trigger are synchronized internally within each system, but there is also an external clock and trigger synchronization between the two systems.
Both of these options are very effective ways of providing a very high number of channels which function together as one system. What is more, Gage provides a complete turnkey system with all the CompuScope cards installed, synchronized and ready to run.
This type of solution is perfect not only for this customer's particular application of testing high-power laser lamps, but also for other applications requiring a large number of synchronized channels, such as Engine Analysis.
PRODUCT RECOMMENDED
Turnkey Option #1: - 2 x 8 Multi-Card CompuScope 512-12 bit, 5 MSPS cards for the ISA bus
- GagePC in special chassis
- Custom Power Supply
- Internal Clock In to Clock Out Modification
- Internal Trigger In to Trigger Out Modification
Turnkey Option #2: - 4 x 8 Multi-Card CompuScope 512-12 bit, 5 MSPS cards for the ISA bus
- 2 x GagePC in special chassis (one without CPU)
- ISA Bus Expansion Kit
- Custom Power Supply
- Internal Clock In to Clock Out Modification
- Internal Trigger In to Trigger Out Modification
- External Clock In to Clock Out Modification
- External Trigger In to Trigger Out Modification
This application note is provided "as is" without any warranties of any kind, either expressed or implied, including but not limited to the implied warranties of merchantability or fitness for a particular purpose. Gage Applied Technologies further does not warrant the accuracy and completeness of the material contained herein. Gage Applied Technologies may make changes to this material, or to the products described in it, at any time without notice.
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