TDC1000-TDC7200EVM: Question for TDC1000-TDC7200EVM

Annie Liu

Part Number: TDC1000-TDC7200EVM

Hi Team,

Scene: Gas Meter Application

Installation: Transducer (200Khz)

Calculation: Get the transmission and reception time via TDC7200+TDC1000. (Use the time difference method to calculate the flow rate)

Configuration:
uint8_t TDC7200_reg_local_copy[10] = {0x02, 0x44, 0x07, 0x07, 0xFF, 0xFF, 0xFF, 0xFF, 0x0, 0x0 };
uint8_t TDC1000_reg_local_copy[10] = {0x25, 0x00, 0x01, 0x00, 0x00, 0xE0, 0x00, 0x00, 0x23, 0x00};

Question:
The time taken by the TDC time is not accurate. In a closed environment, the time of each measurement changes greatly. There are hundreds of ns. Customer would like to know what factors will affect this time?

Thanks.
Annie

over 5 years ago

0 Bharat Aravamudhan over 5 years ago

TI__Genius 11015 points

Annie,

Let me review this info and get back with you by this Friday.

0 Annie Liu over 5 years ago in reply to Bharat Aravamudhan

TI__Genius 10295 points

Hi Bharat,

Is there any update for this case?

Thanks.

0 Bharat Aravamudhan over 5 years ago in reply to Annie Liu

TI__Genius 11015 points

Annie,

Our labs were closed all of last week, I will check on this issue this week and update you before this thursday.

0 Annie Liu over 5 years ago in reply to Bharat Aravamudhan

TI__Genius 10295 points

Hi Bharat,

I would appreciate it if you could share me your update?

Thanks.

Annie

0 Bharat Aravamudhan over 5 years ago

TI__Genius 11015 points

Annie,

Please note the below conditions can vary the readings especially in the ns ranges.

1. The 2 transducers could have some impedance miss matches, it is recommended to have same transducers on either end of the RX/Tx sides.

2. Some small disturbances in the gas flow or jitter can cause the readings to be unstable.

Please refer to the documents below on the Analog Electrical Design for better Gas Flow metering applications: These documents provide more details for accurate gas flow metering.

http://www.ti.com/lit/an/snaa284a/snaa284a.pdf

http://www.ti.com/lit/an/snia020/snia020.pdf

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TDC1000-TDC7200EVM: Question for TDC1000-TDC7200EVM