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TDC1000-TDC7200EVM: TDC1000-TDC7200EVM

Christian Ngotchie
Prodigy 120 points

Part Number: TDC1000-TDC7200EVM

Hello,
I am new to the use of tdc1000tdc7200 and would like to configure the MCU for a level measurement between 1 cm and 60 cm.

I have two problems:
1- When I get a configuration that measures more than 30 cm, the same configuration does not measure less than 13 cm. The parameters AUTOZERO_PERIOD and CLOCKIN_DIV of TDC1000_Clock_Rate seriously influence the distance.
2- the smallest measurement I get does not go below 2.73 cm.

Your help will help me with the rest. Thank you

Below you will find my configuration of the tdc1000 registers.

  • 0
    Prodigy 120 points

    Fullscreen TDC1000_Setup 27.35cm.txt Download 
    TDC1000_Config0                         5F
TDC1000_Config1                         65
TDC1000_Config2                         10
TDC1000_Config3                         05
TDC1000_Config4                         00
TDC1000_TOF-1                           E0
TDC1000_TOF-0                           28
TDC1000_Error_Flags                     00
TDC1000_Timeout                         3B
TDC1000_Clock_Rate                      07
TDC1000_Conts_Trigger                   00
TDC7200_Config1                         02
TDC7200_Config2                         44
TDC7200_Interrupt_Status                00
TDC7200_Interrupt_Mask                  00
TDC7200_Coarse_Cntr_Ov_H                FF
TDC7200_Coarse_Cntr_Ov_L                FF
TDC7200_Clock_Cntr_Ov_H                 FF
TDC7200_Clock_Cntr_Ov_L                 FF
TDC7200_Clock_Cntr_Stop_Mask_H          00
TDC7200_Clock_Cntr_Stop_Mask_L          00
TRIGGER_UPDATE_FREQ                     0001
TDC_AVG/STDEV_NUM_ELEMS                 0002
SAVE_GRAPH_DATA_TO_FILE                 00
FLOW_MODE_SELECT                        00
Y-SCALE_CENTER                          0032
X-SCALE_RANGE                           0032
MEASURE_RTD1                            01
SAVE_RESULT_REGR_TO_FILE                00
GRAPH_MULTI_STOPS                       00
TDC_SELECT                              02
TEMP_RTD_SELECT                         00
TEMP_RTD_MODE                           01
TEMP_AVG/STDEV_NUM_ELEMS                000A
SAVE_TEMP_DATA                          00
GRAPH_YMAX_DATA                         000000000005A4F6
GRAPH_YMIN_DATA                         000000000005A492
TDC1000-HV_DRV_EN1                      00
TDC1000-HV_DRV_EN2                      00
HV_DRV_EN1_Period                       001E
HV_DRV_EN2_Period                       001E
ENABLE_POWER_CYCLE                      00
CLK_FREQ_(1-16MHz)                      8,000000
CLK_SOURCE_SEL                          00
CPU_CLK_FREQ                            05
CPU_CLK_EN                              00
TDC1000-HV_BST_PWR_EN                   00
HV_BST_PWR_EN_Period                    0000
FWD2REV_FLOW_DELAY                      0000
TDC1000-IMPE_MATCH_EN                   01
ENABLE_UART_STREAM                      00
ENABLE_MSP430TIMER_TDC                  00

  • 0
    TI__Genius 11015 points
    Christian,

    The ability of the device to measure a large range of 1 cm to 60 cm will depend on the transducer as well as the device settings.
    Typically at very small distance the transducers ringing will affect its ability to decode the receiving signal and we may need to use blanking/short distance measurement mode of the device.
    We suggest that you characterize the transducer and the device to use an optimal device settings using the following settings:
    1. Check the Rx signal at both the longest distance and the shortest distance and see which Echo_Qual_Thld & PGA_GAIN settings would detect both at the highest & lowest level of water.
    2. At the highest distance sometimes the reflections could be from the sides of the tank and that could give error readings, this could be avoided mechanically by making sure the transducer receives only the reflections from the top of the liquid measurement.
  • 0 in reply to Bharat Aravamudhan
    Prodigy 120 points

    Thank you Bharat.
    I will put your suggestions into practice and keep you informed.

  • 0 in reply to Bharat Aravamudhan
    Prodigy 120 points

    I have modified these Settings as follows:

    PGA_GAIN : 15dB

    ECHO_QUAL_THLD : -220mV

    NUM_RX : 1 STOP

    I attach a capture of other configurations from the TDC1000 tab.

    With this configuration, the measuring range is from 3.5cm to 8.5cm

    Take a look at it, please.

    Is there any setting on the TDC7200 tab or on another tab?

  • 0 in reply to Bharat Aravamudhan
    Prodigy 120 points

    With this other configuration, the measuring range is from 12.01cm to more than 28cm

  • 0 in reply to Christian Ngotchie
    TI__Genius 11015 points
    Christian,

    The TDC1000-TDC7200EVM measures the ToF of the ultrasonic waves between the time the transducer transmits it and receives it back.

    The TDC1000 receives the return signal and amplifies it to generate the necessary stop pulses. The strength of the return pulse will vary as the medium as well as the distance changes and hence it will be difficult to set a particular gain & VCOM setting and measure a wide range of distance.

    Please let me know if you would just like to know if the a standard gain and VCOM setting can be used to measure the complete distance of 2cm to 60cm ?

    Also in the TDC7200 tab please make sure you match the average cycle & NUM STOP with that of the TDC1000 tab.