4.5 Data System

 

4.5.10 Rate and Composition Aperture Data

 

Rate and CA data will be output as five sets of data, each set the result of one spin pair (spin group pair). Each spin pair produces 478 bytes of data. The sequence of data types for odd and even spins is shown in Table 4.15. Rate channels are P1 - P8, P1' - P8', E1 - E5; E1' - E5', FP6 - FP7, FP6' - FP7', DE1 - DE4, DE1 - DE4, S1, S2 and W1 - W8. CA channels are c1, c2, d1, d2, and P. Rate data will consist of four bits of exponent and four bits of mantissa: ABCD. EFGH. The value = A x 27 + ... + H x 20, where A is the MSB and H the LSB. CA channel P will define the data type represented by the pairs (C1, D1) and (C2, D2), and the event-priority schedule used to choose these events for sampling as shown in Figure 4.41.

 

Figure 4.41 CA priority byte

 

 

 

Type E(I,II) 2 E(I,II) 1 Element 00 H 01 He 10 O 11 Fe

Schedule S1   0 0 1 1 S0   0 1 0 1 Priority 1 Fe O H He   2 O Fe Fe Fe   3 He H O O   4 H He He H

 

Table 4.15 Science data rate and CA one spin pair  (same as Table 2.14)

 

The status trailer contains data to provide timing accuracy and indicate the validity of rate and CA data. The structure of the status trailer is shown below in Figure 4.42.

 

Figure 4.42a Status trailer format

 

 

 

Figure 4.42b Status trailer format, continued

 

 

 

Next: Chapter 4.5.11: Sectoring