TAOS TSL230RD Скачать руководство пользователя страница 6

An Evaluation System for the TAOS Light-to-Frequency Converters 

 

 

 

www.taosinc.com

 

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types of daughterboard windows – one for the TSL230RD daughterboard which does not utilize and 

LED, and one for the other five daughterboards which utilize LEDs. 
 

TSL230RD Daughterboard Window 

The TSL230RD daughterboard window provides a graphical representation of the programmable 

features of the TSL230RD device. The TSL230RD daughterboard window can be seen on the right in 

Figure 2. Buttons are used to control the state of the sensitivity and output scaling input programming 
lines on the evaluation device. The pattern of squares in the middle of the picture represents the 

configuration of active photodiodes in the 100x, 10x, and 1x sensitivity modes. For more information 

on the TSL230RD please refer to the TAOS TSL230RD Programmable Light-to-Frequency Converter 

datasheet. 

 

Integration Time 

A slider provides adjustment of integration time between 0.01s and 3s for the frequency measurement 

of the TSL230RD evaluation device. See the section “Measurement Mode” for more information on 

frequency measurement. 

 

Other Daughterboard Windows 

The TSL235R, TSL237S, TSL237T, TSL245R, and TSL238D daughterboards share a common set of 

features and therefore share a common window format. This daughterboard window format is shown 

on the left in Figure 2. Controls are provided for LED brightness and sensor integration time, along 

with several measurement options involving the use of the LED source. 
 

LED Drive Duty Cycle 

The EVM uses a pulse width modulation technique to control the brightness of the LED on the 

daughterboard. Pulse width modulation varies the duty cycle, or percentage of time that the signal is 

high, of the drive signal to the LED. This drive signal is then low-pass filtered to provide a continuous 
DC signal. If the duty cycle is low, then the percentage of time that the LED is on is low (near 0%), 

and the average power, and thus the brightness, is low. If the duty cycle is high (near 100%), then 

the average power delivered to the LED is nearly maximum level. The duty cycle is controlled by an 8-

bit value (0-255) input using the LED Drive Duty Cycle slider. 

 

Strobe 

The Strobe option controls whether the LED is turned off after the frequency measurement is made. If 

the Strobe check box is checked, then the LED will be turned on just before the measurement is 

made, and turned off after making the measurement. When the LED is turned on, it will be set to the 

brightness determined by the LED Drive Duty Cycle setting. Turning off the LED between 

measurements will prevent the light from one daughterboard from affecting the measurements of an 
adjacent daughterboard, and will minimize heating of the LED at high brightness levels.

 

 
Integration Time 

A slider provides adjustment of integration time between 0.01s and 3s for the frequency measurement 

of the TSL230RD evaluation device. See the section “Measurement Mode” for more information on 
frequency measurement. 

 
Measurement Options 

There are two measurement options that may be activated when making measurements with the on-
board LED. The ambient subtraction option is activated when the Subtract Ambient check box is 

checked. When this option is activated, each time the sensor is measured, and extra measurement is 

made with the LED off. This value is stored and displayed as “Ambient”. This value is then subtracted 

from the actual frequency measurement and the subtracted value is displayed in the reading window. 

The calculation used is as follows: 

Содержание TSL230RD

Страница 1: ...opriate drive letter in the above command to install the software CD ROMs are commonly D The installation program will guide you through the product installation Refer to the ReadMe file on CD for the latest installation instructions USB EVM HARDWARE AND DRIVER DESCRIPTION The specification and system requirements for the hardware portion of the Light to Frequency LTF EVM USB module follow System ...

Страница 2: ...ith each daughterboard and these are labeled A and B on the motherboard Frequency measurements period measurements and PWM control of the daugherboard LEDs are performed by either the BASIC Stamp or the coprocessors under BASIC Stamp control The EVM is shipped with an application programmed into the BASIC Stamp which controls the communication between the BASIC Stamp the sensor coprocessors and th...

Страница 3: ...connector on the bottom of the daughterboard with either of the sockets A or B Note that the connector is polarized and the daughterboard should be inserted such that the two mounting holes in the corners opposite the side with the connector align over the threaded standoffs on the motherboard Press firmly over the connector to make sure that the daughterboard is seated firmly in the socket As exp...

Страница 4: ...ly a Strip Chart recorder window can be invoked which displays the data in a graphical representation Each window is explained in more detail in the following sections Figure 2 Light to Frequency EVM Main Window Control Window The control window appears at the far left of the main application window It provides control over measurement mode and measurement update rate of both daughterboard windows...

Страница 5: ...ives a relatively high count value in a reasonable amount of time integration time For lower frequencies a longer integration time is required to get a high count value high resolution In this case Period measurement mode can be used which will result in a higher count value in a shorter amount of time since only the measurement of one period or cycle is required For very low frequencies less than...

Страница 6: ...y cycle or percentage of time that the signal is high of the drive signal to the LED This drive signal is then low pass filtered to provide a continuous DC signal If the duty cycle is low then the percentage of time that the LED is on is low near 0 and the average power and thus the brightness is low If the duty cycle is high near 100 then the average power delivered to the LED is nearly maximum l...

Страница 7: ...ed as the standard for subsequent measurements The ratiometric measurement is calculated as follows Reading Signal Reference Note that both measurement options can be used together In this case the following calculation is used Reading Signal Ambient Ambient Reference Ambient Ambient Strip Chart The Strip Chart window is invoked by selecting menu option View Strip Chart The Strip Chart is a graphi...

Страница 8: ...An Evaluation System for the TAOS Light to Frequency Converters www taosinc com 8 of 10 Appendix ...

Страница 9: ...An Evaluation System for the TAOS Light to Frequency Converters www taosinc com 9 of 10 ...

Страница 10: ...An Evaluation System for the TAOS Light to Frequency Converters www taosinc com 10 of 10 ...

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