EDI CTT-2 Manuale operativo - Pagina 3

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2.1.3

is made. A short delay will speed up the sweep at the expense of accuracy. A delay of

1000uS is a good compromise between speed and accuracy.

2.2

A typical sweep test for a 200 KHz transducer would cover a range of 170 to 230

Khz using 100 Hz steps. The number of steps required will be the sweep width divided by

the frequency step. In this example, the frequency sweeps from 170 to 230 Khz for a width

of 60KHz. Using 100Hz steps this will require a total of 600 steps to cover the range. The

recommended delay should be left at 1000uS. The 'Sf' command sets the frequency step,

'Ss' sets the number of steps, and 'Sd' sets the step delay. Typing 'S' will display the current

frequency step, number of steps, and delay. For this example, type 'Ss600' to set the

sweep for 600 steps.

2.3

To start the sweep, type 'sm170000' and the sweep will start at 170KHz and

continue for 600 steps to 230KHz. When the sweep is finished the maximum and minimum

impedances found will be displayed along with the frequency that they ocurred at. If

impedance data for each frequency step is desired, use the command 'sa170000' and the

impedance and relative phase will be returned for each frequency step.

3 Spot frequency tests measure the impedance at a single frequency. To check the impedance of

the transducer at 197KHz, type 'f197000'. To read both impedance and the relative phase, type

'fa197000'. The 'f+' command will increment the frequency one step, and the 'f-' commad will

decrement the frequency one step. The impedance and relative phase are returned.

4 Leakage testing is done with the 'l' command, and returns the resistance of the transducer. The

leakage test takes 3 to 10 seconds, the longer time will read higher resistances. A minimum

delay of 3000mS is required. To set a 5 second delay, type 'Ld5000'. Note that the commands

are case sensitive.

5 The three indicator lights on the front panel can be turned on, off , or flashed to indicate what

action is to be taken during the test. To light the left most (green) LED, type 'I1', to extinguish

the LED, type 'i1'. The LED's are numbered from left to right 1, 2, and 3. The corresponding

colors are green, yellow, and orange. Typing 'I2' lights the yellow LED, and 'I3' lights the

orange one. To make a LED1 blink, type 'Ib1' and the green LED will begin flashing. To stop

the LED from flashing type 'i1'.

6 Returned data format

Two data formats are provided, one returns descriptive data, and the other returns only comma

separated (CSV) data. When first trying out the CTT232, is is easier to use the default

descriptive data that returns data in the form F= 100000, Z = 257 instead of the CSV that will

only return 100000,257. The 'p' command switches to CSV data. To go back to the descriptive

data, type 'P'.

CTT-2 Manual V1.01

The delay is the time that the frequency is held constant before the measurement