Part Number: TDC1000-TDC7200EVM
Dear sir / madam,
I am using your TDC1000-TDC7200EVM with our ultrasonic flow sensor for flow measurement.
The configuration files for the EVM is attached.
I am using a 2” pipe with 2, STEMiNC ultrasonic flow sensors of 1MHz
(Model : SMFM21F1000SS) connected at 45⁰ on opposite ends of pipe facing each other.
The 2” pipe ID is 54.8mm and the ultrasonic path length between the two sensors is 77.5mm.
I connected the ultrasonic flow sensor on my test rig with a master electromagnetic flow meter.
My observations during the test were that at 28m3/hr flow rate the expected time difference should be between 196.6ns. But the actual time difference is 140ns with variation in the time of ±20ns. Why is that so? Why the time difference not stable? (Note that I have provided straight lengths of 10D on upstream and downstream.) Same is the case with 21m3/hr, 14m3/hr, 7m3/hr & 0m3/hr.(Kindly find attached log file generated by EVM PC utility for your reference.)
In this regard I would like to seek your valuable guidance.
1. How can I stabilize the variation in delta T ?
2. Why is the difference of time observed different from that calculated?
By adjusting the K factor the flow rate can be adjusted but how to stop the variations in
time.
Also, note that I have used shielded cable from the sensor to the EVM board.(No loose connections or contact problems observed).
TDC1000_Config0 45 TDC1000_Config1 45 TDC1000_Config2 12 TDC1000_Config3 03 TDC1000_Config4 00 TDC1000_TOF-1 E0 TDC1000_TOF-0 1E TDC1000_Error_Flags 00 TDC1000_Timeout 21 TDC1000_Clock_Rate 02 TDC1000_Conts_Trigger 00 TDC7200_Config1 02 TDC7200_Config2 44 TDC7200_Interrupt_Status 07 TDC7200_Interrupt_Mask 07 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 0009 TDC_AVG/STDEV_NUM_ELEMS 000A SAVE_GRAPH_DATA_TO_FILE 01 FLOW_MODE_SELECT 01 Y-SCALE_CENTER 0032 X-SCALE_RANGE 0032 MEASURE_RTD1 01 SAVE_RESULT_REGR_TO_FILE 01 GRAPH_MULTI_STOPS 01 TDC_SELECT 00 TEMP_RTD_SELECT 00 TEMP_RTD_MODE 00 TEMP_AVG/STDEV_NUM_ELEMS 000A SAVE_TEMP_DATA 00 GRAPH_YMAX_DATA 00000000000000C6 GRAPH_YMIN_DATA 0000000000000062 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 00 ENABLE_UART_STREAM 00 ENABLE_MSP430TIMER_TDC 00
