SNLA428 june   2023 DP83826E

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Time Domain Reflectometry
    1. 1.1 Example Connections
      1. 1.1.1 Open Circuit Cable
      2. 1.1.2 Short Circuit Cable
  5. 2TDR Implementation
    1. 2.1 DP83826 TDR Configuration
    2. 2.2 TDR Algorithm
      1. 2.2.1 TDR Algorithm Example Flow
      2. 2.2.2 TDR Algorithm Matlab Example Code
  6. 3Summary
  7. 4References

TDR Algorithm

This section describes how to process the TDR register data. All of the following steps must be carried out in code.

  1. Define 6x3 matrix from the table you entered in the section DP83826 TDR configuration. Then, define each column as an array and name them peak_index, peak_value, and peak_sign.
  2. Initialize the following variables:
    Table 2-3 Initial Variables
    Variable Type Initial Value Description
    i int 5 Current row of the matrix
    threshold int 10 The threshold that peak_indx must exceed for a fault to be detected
    fault_detected bool FALSE Defines whether a fault has been detected
    fault_location float 0 Fault location
    prop_dly float Propogation delay variable. This value can be adjusted based on the cable type. See the Prop_dly Values table for suggested values for different cable types.
    offset int 5 Variable used in calculating the fault location.
    fault int 0 Defines whether a fault is a SHORT (1) or an OPEN (0) fault
    Table 2-4 Prop_dly Values
    Cable type Prop_dly
    Cat5/5e 5.35
    Cat6 5
    Cat7 4.6
  3. Write a program with the following algorithm. See the TDR Algorithm Example Flow and MATLAB example code below for reference.
    GUID-20230524-SS0I-2MQF-VFQZ-K2C8NBKB5WPM-low.svg Figure 2-1 DP83826 TDR Algorithm
  4. The fault type is in the Fault variable and the fault location is stored in fault_location.