**I****EEE P1451.3 Proposal**

+-----------------+----------------------------------------------------+
| Proposal Title: | Pre-trigger acquisition                            |
+-----------------+----------------------------------------------------+
| Proposal        | 2002-23                                            |
| Number:         |                                                    |
+-----------------+----------------------------------------------------+
| Revision        |                                                    |
| Number:         |                                                    |
+-----------------+----------------------------------------------------+
| Date:           | 10/12/02                                           |
+-----------------+----------------------------------------------------+
|                 |                                                    |
+-----------------+----------------------------------------------------+
| Name:           | Lee Eccles                                         |
+-----------------+----------------------------------------------------+
| Company:        | Boeing Commercial Airplanes                        |
+-----------------+----------------------------------------------------+
| Phone Number:   | \(206\) 655-2824                                   |
+-----------------+----------------------------------------------------+
| Fax Number:     | \(206\) 655-7724                                   |
+-----------------+----------------------------------------------------+
| Email Address:  | Lee.h.eccles@boeing.com                            |
+-----------------+----------------------------------------------------+
|                 |                                                    |
+-----------------+----------------------------------------------------+
| Proposal        | Initial Draft                                      |
| Status:         |                                                    |
|                 | Revised Draft                                      |
|                 |                                                    |
|                 | Ready for Vote                                     |
+-----------------+----------------------------------------------------+
| Impacts:        | \_\_                                               |
|                 |                                                    |
|                 | \_\_                                               |
+-----------------+----------------------------------------------------+
| Action:         | \_[X]{.underline} Approved                         |
|                 |                                                    |
|                 | \_\_ Approved with changes                         |
|                 |                                                    |
|                 | \_\_ Rejected                                      |
|                 |                                                    |
|                 | \_\_ Returned for revision                         |
+-----------------+----------------------------------------------------+
|                 |                                                    |
+-----------------+----------------------------------------------------+

Background:

**Catlin-11**

4.6 -- Standard does not allow for pre-trigger acquisition of data.

This proposal assumes that proposal2002-19 has been accepted.

The proposal below should be considered a starting point for discussion.

Proposal:

#### 5.6.1.2 Free-running without pre-trigger {#free-running-without-pre-trigger .unnumbered}

In the free-running sampling mode, a sensor is measuring some physical
parameter autonomously and continuously when in the operating state. The
data being acquired and converted is discarded until a trigger is
received. Once a trigger has been received, the next sample converted is
stored in the TBIM as the first word in the data set. Consecutive
samples are stored in the TBIM until the entire data set is completed.
At this point, the TransducerChannel returns to discarding samples until
the next trigger is received. The sampling operation of a
TransducerChannel when in the halted state is at the discretion of the
manufacturer.

An actuator operating in the free-running sampling mode shall apply the
data set received before the trigger in accordance with its
End-of-data-set Operating mode.

#### 5.6.1.3 Free-running with pre-trigger {#free-running-with-pre-trigger .unnumbered}

The following two sub-clauses describe the operation of a sensor when
operating in the free-running mode with or without buffers enabled.

An actuator may not be operated in the free-running with pre-trigger
mode.

#### 5.6.1.3.1 Free-running with pre-trigger without buffers enabled {#free-running-with-pre-trigger-without-buffers-enabled .unnumbered}

In the free-running sampling mode, a sensor is measuring some physical
parameter autonomously and continuously when in the operating state. The
data being acquired and converted is stored until a trigger is received
or the pre-trigger count (see 6.1.1.4) is reached. After the number of
samples that have been stored reaches the pre-trigger count, the next
sample acquired shall cause the oldest sample to be discarded and the
new sample stored. After a trigger has been received, the next sample
converted is stored in the TBIM as the next word in the data set.
Consecutive samples are stored in the TBIM until the entire data set is
completed. The data set shall be complete when the number of samples
equal to the *data set size* minus the *pre-trigger count* has been
acquired after the trigger is received. At this point the
TransducerChannel returns to discarding samples until the next trigger
is received or the data set is read. After the data set is read the
TransducerChannel shall start storing samples again while waiting for
another trigger. In this mode the data set may only be read once.
Subsequent reads before the next trigger will return zero octets. The
sampling operation of a TransducerChannel when in the halted state is at
the discretion of the manufacturer.

#### 5.6.1.3.1 Free-running with pre-trigger and buffers enabled {#free-running-with-pre-trigger-and-buffers-enabled .unnumbered}

In the free-running sampling mode, a sensor is measuring some physical
parameter autonomously and continuously when in the operating state. The
data being acquired and converted is stored until a trigger is received
or the pre-trigger count (see 6.1.1.4) is reached. After the number of
samples that have been stored reaches the pre-trigger count, the next
sample acquired shall cause the oldest sample to be discarded and the
new sample stored. Once a trigger has been received, the next sample
converted is stored in the TBIM as the next word in the data set.
Consecutive samples are stored in the TBIM until the entire data set is
completed. The data set shall be complete when the number of samples
equal to the data set size minus the pre-trigger count has been acquired
after the trigger is received. The TransducerChannel shall switch to the
next empty buffer and start acquiring data samples for the next data
set. If no empty buffers are available it shall discard any samples
acquired until a buffer becomes available. A buffer shall be considered
available after it has been read. The sampling operation of a
TransducerChannel when in the halted state is at the discretion of the
manufacturer.

### 6.1.1 Initialization commands {#initialization-commands .unnumbered}

No text changes

Table 1---Initialization commands

  ---------- -------------------------------------------------------- --------- ------------------- ------- -------- ------- -----------
  Function   Command                                                  Address                                                Required/
                                                                                                                             Optional

                                                                      TBIM      TransducerChannel           Global   Group   

                                                                                Normal              Proxy                    

  0          Reserved                                                 ---       ---                 ---     ---      ---     ---

  1          [Sleep](#sleep)                                          Yes       Yes                 Yes     Yes      Yes     Optional

  2          [Wake-up](#_Wake-up_command)                             Yes       Yes                 Yes     Yes      Yes     Optional

  3          [Set TransducerChannel data repetition                   Yes       Yes                 No      Yes      Yes     Optional
             count](#_Ref15648392)                                                                                           

  4          Set TransducerChannel pre-trigger count                  Yes       Yes                 No      Yes      Yes     Optional

  5          [Calibrate TransducerChannel](#_Reset_command)           Yes       Yes                 Yes     Yes      Yes     Optional

  6          [Zero TransducerChannel](#_Ref536866645)                 Yes       Yes                 Yes     Yes      Yes     Optional

  7          [Logical CommunicationsChannel                           No        Yes                 Yes     No       No      Required
             assignment](#_Logical_CommunicationsChannel_assignmen)                                                          

  8          [Enable corrections](#_Enable_corrections)               Yes       Yes                 Yes     No       No      see 0

  9          [Disable corrections](#_Ref13141011)                     Yes       Yes                 Yes     No       No      see 0

  10         [Enable transducer](#_Enable_transducer)                 Yes       Yes                 Yes     Yes      Yes     Required

  11         [AddressGroup definition](#_Enable_transducer)           Yes       Yes                 Yes     No       No      Required

  12 -- 127  Reserved                                                 ---       ---                 ---     ---      ---     ---

  128 -- 255 Open for manufacturers                                   ---       ---                 ---     ---      ---     ---
  ---------- -------------------------------------------------------- --------- ------------------- ------- -------- ------- -----------

#### 6.1.1.1 Sleep {#sleep .unnumbered}

No text changes

#### 6.1.1.2 Wake-up {#wake-up .unnumbered}

[]{#_Ref15648392 .anchor}No text changes

#### 6.1.1.3 Set TransducerChannel data repetition count {#set-transducerchannel-data-repetition-count .unnumbered}

No text changes

#### 6.1.1.4 Set TransducerChannel pre-trigger count {#set-transducerchannel-pre-trigger-count .unnumbered}

This command is used by Transducerchannels that are capable of being
operated in the free-running with pre-trigger mode to change the number
of data samples in a data set that can be acquired and stored before the
receipt of a trigger. This number may be any number between zero the
number found in the *Maximum data repetitions* field of the
TransducerChannel TEDS. The only argument to this command is a
sixteen-bit integer. If the value of the argument exceeds the *Maximum
data repetitions*, the pre-trigger count shall be set to the *Maximum
data repetitions* and the *TBIM invalid command* bit shall be set in the
status register.

If an acknowledgment is required for this command, the reply shall
contain the thirty-two-bit status word for the TBIM in the data field
(see **5.10**).

#### 6.1.1.5 Calibrate TransducerChannel {#calibrate-transducerchannel .unnumbered}

[]{#_Ref536866645 .anchor}No text changes

#### 6.1.1.6 Zero TransducerChannel {#zero-transducerchannel .unnumbered}

No text changes

#### 6.1.1.7 Logical CommunicationsChannel assignment {#logical-communicationschannel-assignment .unnumbered}

No text changes

#### 6.1.1.8 Enable corrections {#enable-corrections .unnumbered}

[]{#_Ref13141011 .anchor}No text changes

#### 6.1.1.9 Disable corrections {#disable-corrections .unnumbered}

[]{#_Enable_transducer .anchor}No text changes

#### 6.1.1.10 Enable TransducerChannel {#enable-transducerchannel .unnumbered}

No text changes

#### 6.1.1.11 AddressGroup definition {#addressgroup-definition .unnumbered}

No text changes

### 6.1.7 Set operating mode commands {#set-operating-mode-commands .unnumbered}

No text changes

Table 21---Operating mode command functions

  ---------- ----------------- ------------------------ ------- ---------------
  Function   Operational mode  **Choices**              Value   Related TEDS
                                                                Field

  0          Reserved          ---                      ---     ---

  1          Sampling mode     Trigger-initiated        1       Table 45

                               Free-running without     2       
                               pre-trigger                      

                               Free-running with        3       
                               pre-trigger                      

  2          Buffered mode     Unbuffered               1       Table 46

                               Buffered                 2       

  3          End-of-data-set   Hold                     1       Table 47
             operation                                          

                               Recirculate              2       

  4          Streaming mode    Off                      1       Table 48

                               On                       2       

  5          Edge-to-report    Rising                   1       Table 49
             mode                                               

                               Falling                  2       

                               both                     3       

  6          Actuator-halt     Hold                     1       Table 50

                               Finish data set          2       

                               Ramp                     3       

  7 - 127    Reserved          ---                      ---     ---

  128 - 255  open to           ---                      ---     ---
             manufacturers                                      
  ---------- ----------------- ------------------------ ------- ---------------

## 7.4 TransducerChannel TEDS {#transducerchannel-teds .unnumbered}

No text changes

### 7.4.1 Access {#access .unnumbered}

No text changes

### Data block

No text changes

Table 38---Structure of the TransducerChannel TEDS data block

  ------- ------------------------------------------------- -------- --------
  Field   Description                                       Type     \#
                                                                     octets

  ---     TEDS length                                       U32L     4

  1       TEDS identifier                                   U8E      1

  ---     TransducerChannel related information             ---      ---

  2       Calibration key                                   U8E      1

  3       TransducerChannel type key                        U8E      1

  4       Physical units                                    UNITS    10

  5       Lower range limit                                 F32      4

  6       Upper range limit                                 F32      4

  7       Worst-case uncertainty                            F32      4

  8       Self-test key                                     U8E      1

  ---     Data converter related information                ---      ---

  9       Data model                                        U8E      1

  10      Data model length                                 U8C      1

  11      Model significant bits                            U16C     2

  12      Maximum data repetitions                          U16C     2

  13      Series origin                                     F32      4

  14      Series increment                                  F32      4

  15      Series units                                      UNITS    10

  16      Maximum pre-trigger samples                       U16C     2

  ---     Timing related information                        ---      ---

  17      TransducerChannel update time (t~u~)              F32      4

  18      TransducerChannel write setup time (t~ws~)        F32      4

  19      TransducerChannel read setup time (t~rs~)         F32      4

  20      TransducerChannel sampling period (t~sp~)         F32      4

  21      TransducerChannel warm-up time                    F32      4

  22      TransducerChannel read delay time (t~ch~)         F32      4

  23      TransducerChannel self-test time requirement      F32      4

  ---     Time of the sample information                    ---      ---

  24      Source for the time of sample                     U8E      1

  25      Incoming propagation delay through the data       F32      4
          transport logic with sync                                  

  26      Incoming propagation delay through the data       F32      4
          transport logic without sync                               

  27      Outgoing propagation delay through the data       F32      4
          transport logic                                            

  28      Trigger-to-sample delay uncertainty with sync     F32      4

  29      Trigger-to-sample delay uncertainty without sync  F32      4

  ---     Attributes                                        ---      ---

  30      Sampling attribute                                U8E      1

  31      Buffered attribute                                U8E      1

  32      End-of-data-set operation attribute               U8E      1

  33      Streaming attribute                               U8E      1

  34      Edge-to-report attribute                          U8E      1

  35      Actuator-halt attribute                           U8E      1

  ---     Sensitivity                                       ---      ---

  36      Sensitivity direction                             F32      4

  37      Direction angles                                  Two F32  8

  ---     Options                                           ---      ---

  38      Event sensor options                              U8E      1

  ---     Checksum                                          U16C     2
  ------- ------------------------------------------------- -------- --------

#### 7.4.2.1 TEDS identifier  {#teds-identifier .unnumbered}

No text changes

#### 7.4.2.2 Calibration key {#calibration-key .unnumbered}

No text changes

#### 7.4.2.3 TransducerChannel type key {#transducerchannel-type-key .unnumbered}

No text changes

#### 7.4.2.4 Physical units {#physical-units .unnumbered}

No text changes

#### 7.4.2.5 Lower range limit {#lower-range-limit .unnumbered}

No text changes

#### 7.4.2.6 Upper range limit {#upper-range-limit .unnumbered}

No text changes

#### 7.4.2.7 Worst-case uncertainty {#worst-case-uncertainty .unnumbered}

No text changes

#### 7.4.2.8 Self-test key {#self-test-key .unnumbered}

No text changes

#### 7.4.2.9 Data model {#data-model .unnumbered}

No text changes

#### 7.4.2.10 Data model length {#data-model-length .unnumbered}

No text changes

#### 7.4.2.11 Model significant bits {#model-significant-bits .unnumbered}

No text changes

#### 7.4.2.12 Maximum data repetitions {#maximum-data-repetitions .unnumbered}

No text changes

#### 7.4.2.13 Maximum pre-trigger samples {#maximum-pre-trigger-samples .unnumbered}

Data type: unsigned octet integer used for counting (U16C, 2 octets)

This field contains the number, L, of repetitions of the
TransducerChannel value that may be sampled and stored prior to a
trigger when operating in the free-running with pre-trigger mode. Each
repetition represents an additional measurement value produced by the
TransducerChannel, which shall be spaced apart from the initial value
along some axis (for example time) by an amount defined by the
TransducerChannel TEDS fields *Series increment* (7.4.2.14) and *Series
units* (7.4.2.15) respectively. When L is zero, the sensor may not be
operated in the free-running pre-trigger mode.

In operation, the number of TransducerChannel values that may be
acquired and stored prior to a trigger may be set to any value lower
than the contents of this field by issuing the Set TransducerChannel
pre-trigger count command as defined in 6.1.1.4.

When reading or writing data with data repetition count greater than
zero, the order of transmittal shall be with the zeroth (oldest) data
sample transmitted first, the first repetition transmitted second, etc.

#### 7.4.2.14 Series origin {#series-origin .unnumbered}

No text changes

#### 7.4.2.15 Series increment {#series-increment .unnumbered}

No text changes

#### 7.4.2.16 Series units {#series-units .unnumbered}

No text changes

#### 7.4.2.17 TransducerChannel update time {#transducerchannel-update-time .unnumbered}

No text changes

#### 7.4.2.18 TransducerChannel write setup time {#transducerchannel-write-setup-time .unnumbered}

No text changes

#### 7.4.2.19 TransducerChannel read setup time {#transducerchannel-read-setup-time .unnumbered}

No text changes

#### 7.4.2.20 TransducerChannel sampling period {#transducerchannel-sampling-period .unnumbered}

No text changes

#### 7.4.2.21 TransducerChannel warm-up time {#transducerchannel-warm-up-time .unnumbered}

No text changes

#### 7.4.2.22 TransducerChannel read delay time {#transducerchannel-read-delay-time .unnumbered}

No text changes

#### 7.4.2.23 TransducerChannel self-test time requirement {#transducerchannel-self-test-time-requirement .unnumbered}

No text changes

#### 7.4.2.24 Source for the time of sample {#source-for-the-time-of-sample .unnumbered}

No text changes

#### 7.4.2.25 Incoming propagation delay through the data transport logic {#incoming-propagation-delay-through-the-data-transport-logic .unnumbered}

No text changes

#### 7.4.2.26 Incoming propagation delay through the data transport logic without sync {#incoming-propagation-delay-through-the-data-transport-logic-without-sync .unnumbered}

No text changes

#### 7.4.2.27 Outgoing propagation delay through the data transport logic {#outgoing-propagation-delay-through-the-data-transport-logic .unnumbered}

Text not changed

#### 7.4.2.28 Trigger-to-sample delay uncertainty with sync {#trigger-to-sample-delay-uncertainty-with-sync .unnumbered}

Text not changed

#### 7.4.2.29 Trigger-to-sample delay uncertainty without sync {#trigger-to-sample-delay-uncertainty-without-sync .unnumbered}

Text not changed

#### 7.4.2.30 Sampling attribute {#sampling-attribute .unnumbered}

Data type: unsigned 8-bit integer used for enumeration (U8E, 1 octet)

This attribute is used to describe which *Sampling* modes (see 5.6.1)
are support by this TransducerChannel. Table 45 lists the allowable
values for this attribute.

Table 45---Sampling attribute

  -------- --------------------------------------------------------------
  Value    Description

  0        Reserved

  1        This TransducerChannel is only capable of being operated in
           the trigger-initiated sampling mode as described in 5.6.1.1

  2        This TransducerChannel is only capable of being operated in
           the free-running sampling mode without pre-triggering as
           described in 5.6.1.2

  3        This TransducerChannel is only capable of being operated in
           the free-running sampling mode with pre-triggering as
           described in 5.6.1.3

  4        This TransducerChannel may be operated with either the
           trigger-initiated sampling mode or the free-running sampling
           mode without pre-triggering. The trigger-initiated sampling
           mode is the default.

  5        This TransducerChannel may be operated with either the
           trigger-initiated sampling mode or the free-running sampling
           mode with pre-triggering. The trigger-initiated sampling mode
           is the default.

  6        This TransducerChannel may be operated with either the
           trigger-initiated sampling mode or either of the free-running
           sampling modes. The trigger-initiated sampling mode is the
           default.

  7        This TransducerChannel may be operated with either the
           trigger-initiated sampling mode or either of the free-running
           sampling modes. The free-running sampling mode without
           pre-triggering is the default.

  8        This TransducerChannel may be operated with either the
           trigger-initiated sampling mode or either of the free-running
           sampling modes. The free-running sampling mode with
           pre-triggering is the default.

  5 - 255  Reserved
  -------- --------------------------------------------------------------

#### 7.4.2.31 Buffered attribute {#buffered-attribute .unnumbered}

No text changes

#### 7.4.2.32 End-of-data-set operation attribute {#end-of-data-set-operation-attribute .unnumbered}

No text changes

#### 7.4.2.33 Streaming attribute {#streaming-attribute .unnumbered}

No text changes

#### 7.4.2.34 Edge-to-report attribute {#edge-to-report-attribute .unnumbered}

No text changes

#### 7.4.2.35 Actuator-halt attribute {#actuator-halt-attribute .unnumbered}

No text changes

#### 7.4.2.36 Sensitivity direction {#sensitivity-direction .unnumbered}

No text changes

#### 7.4.2.37 Direction angles {#direction-angles .unnumbered}

No text changes

#### 7.4.2.38 Event sensor options {#event-sensor-options .unnumbered}

No text changes