User Tools

Site Tools


ch10_handbook:discrete_data

Export page to Open Document format

DISCRETE DATA

Type 0x28, Discrete Data, Format 0

Reserved for future use.


Type 0x29, Discrete Data, Format 1 (Discrete Data)

Discrete Data, Format 1 packets are used to record the state of discrete digital signals. In general, the discrete data packet will contain multiple values from multiple discrete events.

The layout of the CSDW is shown in Figure 6-32. The uRecordState and uAlignment flags are components of the discrete packet Mode field. See the Chapter 10 standard for further details. The uLength value is the number of Discrete Data message that follow in the packet.

 
struct SuDiscreteF1_ChanSpec 
    { 
    uint32_t    uRecordState    :  1;   // Record on state/time 
    uint32_t    uAlignment      :  1;   // Data alignment 
    uint32_t    uReserved1      :  1;   // 
    uint32_t    uLength         :  5;   // Number of bits 
    uint32_t    uReserved2      : 24;   // 
    }; 

Type 0x29 Discrete Data Format 1 CSDW

The layout of the Discrete Data message is shown in Figure 6-33. Each message contains a time stamp and the state of the discrete data input signals. The suIntraPckTime field in the data structures of represents event time in either 48-bit relative time format derived from the RTC (format shown in Figure 6-5) , or as absolute time. If this time is absolute time, it is in either Chapter 4 weighted 48-bit time (format shown in Figure 6-6) or IEEE 1588 time format (format shown in Figure 6-7).

 
struct SuDiscreteF1 
    { 
    uint64_t    suIntraPckTime;         // Intra-packet time stamp 
    uint32_t    suData;                 // Data about the event 
    }; 

Type 0x29 Discrete Data Format 1 message

The IRIG 07 Chapter 10 and prior standard incorrectly states that Bit 7 of the Packet Flags (in the packet header) is used to determine if the intra-packet time is relative time or absolute time. The correct bit to use is Bit 6. It is anticipated that with will be corrected in a future release


Type 0x2A - 0x2F, Discrete Data, Format 2 - Format 7

Reserved for future use.

ch10_handbook/discrete_data.txt · Last modified: 2014/05/29 14:40 by bob