Telemetry

Telemetry Definition Files

Telemetry definition files define the telemetry packets that can be received and processed from COSMOS targets. One large file can be used to define the telemetry packets, or multiple files can be used at the user's discretion. Telemetry definition files are placed in the target's cmd_tlm directory and are processed alphabetically. Therefore if you have some telemetry files that depend on others, e.g. they override or extend existing telemetry, they must be named last. The easiest way to do this is to add an extension to an existing file name. For example, if you already have tlm.txt you can create tlm_override.txt for telemetry that depends on the definitions in tlm.txt. Note that due to the way the ASCII Table is structured, files beginning with capital letters are processed before lower case letters.

When defining telemetry items you can choose from the following data types: INT, UINT, FLOAT, STRING, BLOCK. These correspond to integers, unsigned integers, floating point numbers, strings and binary blocks of data. Within COSMOS, the only difference between a STRING and BLOCK is when COSMOS reads a STRING type it stops reading when it encounters a null byte (0). This shows up when displaying the value in Packet Viewer or Tlm Viewer and in the output of Data Extractor. You should strive to store non-ASCII data inside BLOCK items and ASCII strings in STRING items.

Printing Data

Most data types can be printed in a COSMOS script simply by doing print(tlm("TGT PKT ITEM")). However, if the ITEM is a BLOCK data type and contains binary (non-ASCII) data then that won't work. COSMOS comes with a built-in method called formatted to help you view binary data. If ITEM is a BLOCK type containing binary try puts tlm("TGT PKT ITEM").formatted (Ruby) and print(formatted(tlm("TGT PKT ITEM"))) (Python) which will print the bytes out as hex.

ID Items

All packets require identification items so the incoming data can be matched to a packet structure. These items are defined using the ID_ITEM and APPEND_ID_ITEM. As data is read from the interface and refined by the protocol, the resulting packet is identified by matching all the ID fields. Note that ideally all packets in a particular target should use the exact same bit offset, bit size, and data type to identify. If this is not the case, you must set TLM_UNIQUE_ID_MODE in the target.txt file which incurs a performance penalty on every packet identification.

Variable Sized Items

COSMOS specifies a variable sized item with a bit size of 0. When a packet is identified, all other data that isn't explicitly defined will be put into the variable sized item. These items are typically used for packets containing memory dumps which vary in size depending on the number of bytes dumped. Note that there can only be one variable sized item per packet.

Derived Items

COSMOS has a concept of a derived item which is a telemetry item that doesn't actually exist in the binary data. Derived items are typically computed based on other telemetry items. COSMOS derived items are very similar to real items except they use the special DERIVED data type. Here is how a derived item might look in a telemetry definition.

ITEM TEMP_AVERAGE 0 0 DERIVED "Average of TEMP1, TEMP2, TEMP3, TEMP4"

Note the bit offset and bit size of 0 and the data type of DERIVED. For this reason DERIVED items should be declared using ITEM rather than APPEND_ITEM. They can be defined anywhere in the packet definition but are typically placed at the end. The ITEM definition must be followed by a CONVERSION keyword, e.g. READ_CONVERSION, to generate the value.

Received Time and Packet Time

COSMOS automatically creates several telemetry items on every packet: PACKET_TIMESECONDS, PACKET_TIMEFORMATTED, RECEIVED_COUNT, RECEIVED_TIMEFORMATTED, and RECEIVED_TIMESECONDS.

RECEIVED_TIME is the time that COSMOS receives the packet. This is set by the interface which is connected to the target and is receiving the raw data. Once a packet has been created out of the raw data the time is set.

PACKET_TIME defaults to RECEIVED_TIME, but can be set as a derived item with a time object in the telemetry configuration file. This helps support stored telemetry packets so that they can be more reasonably handled by other COSMOS tools such as Telemetry Grapher and Data Extractor. You can set the 'stored' flag in your interface and the current value table is unaffected.

The _TIMEFORMATTED items returns the date and time in a YYYY/MM/DD HH:MM:SS.sss format and the _TIMESECONDS returns the Unix seconds of the time. Internally these are both stored as either a Ruby Time object or Python date object.

Example

COSMOS provides a Unix time conversion class which returns a Ruby Time object or Python date object based on the number of seconds and (optionally) microseconds since the Unix epoch. Note: This returns a native object and not a float or string!

Ruby Example:

ITEM PACKET_TIME 0 0 DERIVED "Ruby time based on TIMESEC and TIMEUS"
    READ_CONVERSION unix_time_conversion.rb TIMESEC TIMEUS

Python Example:

ITEM PACKET_TIME 0 0 DERIVED "Python time based on TIMESEC and TIMEUS"
    READ_CONVERSION openc3/conversions/unix_time_conversion.py TIMESEC TIMEUS

Defining PACKET_TIME allows the PACKET_TIMESECONDS and PACKET_TIMEFORMATTED to be calculated against an internal Packet time rather than the time COSMOS receives the packet.

Telemetry Keywords

TELEMETRY

Defines a new telemetry packet

Parameter	Description	Required
Target	Name of the target this telemetry packet is associated with	True
Command	Name of this telemetry packet. Also referred to as its mnemonic. Must be unique to telemetry packets in this target. Ideally will be as short and clear as possible.	True
Endianness	Indicates if the data in this packet is in Big Endian or Little Endian format Valid Values: BIG_ENDIAN, LITTLE_ENDIAN	True
Description	Description of this telemetry packet which must be enclosed with quotes	False

Example Usage:

TELEMETRY INST HEALTH_STATUS BIG_ENDIAN "Instrument health and status"

TELEMETRY Modifiers

The following keywords must follow a TELEMETRY keyword.

ITEM

Defines a telemetry item in the current telemetry packet

Parameter	Description	Required
Name	Name of the telemety item. Must be unique within the packet.	True
Bit Offset	Bit offset into the telemetry packet of the Most Significant Bit of this item. May be negative to indicate on offset from the end of the packet. Always use a bit offset of 0 for derived item.	True
Bit Size	Bit size of this telemetry item. Zero or Negative values may be used to indicate that a string fills the packet up to the offset from the end of the packet specified by this value. If Bit Offset is 0 and Bit Size is 0 then this is a derived parameter and the Data Type must be set to 'DERIVED'.	True
Data Type	Data Type of this telemetry item Valid Values: INT, UINT, FLOAT, STRING, BLOCK, DERIVED	True
Description	Description for this telemetry item which must be enclosed with quotes	False
Endianness	Indicates if the item is to be interpreted in Big Endian or Little Endian format. See guide on Little Endian Bitfields. Valid Values: BIG_ENDIAN, LITTLE_ENDIAN	False

Example Usage:

ITEM PKTID 112 16 UINT "Packet ID"
ITEM DATA 0 0 DERIVED "Derived data"

ITEM Modifiers

The following keywords must follow a ITEM keyword.

FORMAT_STRING

Adds printf style formatting

Parameter	Description	Required
Format	How to format using printf syntax. For example, '0x%0X' will display the value in hex.	True

Example Usage:

FORMAT_STRING "0x%0X"

UNITS

Add displayed units

Parameter	Description	Required
Full Name	Full name of the units type, e.g. Celsius	True
Abbreviated	Abbreviation for the units, e.g. C	True

Example Usage:

UNITS Celsius C
UNITS Kilometers KM

DESCRIPTION

Override the defined description

Parameter	Description	Required
Value	The new description	True

META

Stores custom user metadata

Meta data is user specific data that can be used by custom tools for various purposes. One example is to store additional information needed to generate source code header files.

Parameter	Description	Required
Meta Name	Name of the metadata to store	True
Meta Values	One or more values to be stored for this Meta Name	False

Example Usage:

META TEST "This parameter is for test purposes only"

OVERLAP

(Since 4.4.1)

This item is allowed to overlap other items in the packet

If an item's bit offset overlaps another item, OpenC3 issues a warning. This keyword explicitly allows an item to overlap another and suppresses the warning message.

KEY

(Since 5.0.10)

Defines the key used to access this raw value in the packet.

Keys are often JSONPath or XPath strings

Parameter	Description	Required
Key string	The key to access this item	True

Example Usage:

KEY $.book.title

VARIABLE_BIT_SIZE

(Since 5.18.0)

Marks an item as having its bit size defined by another length item

Parameter	Description	Required
Length Item Name	The name of the associated length item	True
Length Bits Per Count	Bits per count of the length item. Defaults to 8	False
Length Value Bit Offset	Offset in Bits to Apply to Length Field Value. Defaults to 0	False

STATE

Defines a key/value pair for the current item

Key value pairs allow for user friendly strings. For example, you might define states for ON = 1 and OFF = 0. This allows the word ON to be used rather than the number 1 when sending the telemetry item and allows for much greater clarity and less chance for user error. A catch all value of ANY applies to all other values not already defined as state values.

Parameter	Description	Required
Key	The string state name	True
Value	The numerical state value or ANY to apply the state to all other values	True
Color	The color the state should be displayed as Valid Values: GREEN, YELLOW, RED	False

Example Usage:

APPEND_ITEM ENABLE 32 UINT "Enable setting"
  STATE FALSE 0
  STATE TRUE 1
  STATE ERROR ANY # Match all other values to ERROR
APPEND_ITEM STRING 1024 STRING "String"
  STATE "NOOP" "NOOP" GREEN
  STATE "ARM LASER" "ARM LASER" YELLOW
  STATE "FIRE LASER" "FIRE LASER" RED

READ_CONVERSION

Applies a conversion to the current telemetry item

Conversions are implemented in a custom Ruby or Python file which should be located in the target's lib folder. The class must inherit from Conversion. It must implement the initialize (Ruby) or __init__ (Python) method if it takes extra parameters and must always implement the call method. The conversion factor is applied to the raw value in the telemetry packet before it is displayed to the user. The user still has the ability to see the raw unconverted value in a details dialog.

Parameter	Description	Required
Class Filename	The filename which contains the Ruby or Python class. The filename must be named after the class such that the class is a CamelCase version of the underscored filename. For example, 'the_great_conversion.rb' should contain 'class TheGreatConversion'.	True
Parameter	Additional parameter values for the conversion which are passed to the class constructor.	False

Ruby Example:

READ_CONVERSION the_great_conversion.rb 1000

Defined in the_great_conversion.rb:

require 'openc3/conversions/conversion'
module OpenC3
  class TheGreatConversion < Conversion
    def initialize(multiplier)
      super()
      @multiplier = multiplier.to_f
    end
    def call(value, packet, buffer)
      return value * @multiplier
    end
  end
end

Python Example:

READ_CONVERSION the_great_conversion.py 1000

Defined in the_great_conversion.py:

from openc3.conversions.conversion import Conversion
class TheGreatConversion(Conversion):
    def __init__(self, multiplier):
        super().__init__()
        self.multiplier = float(multiplier)
    def call(self, value, packet, buffer):
        return value * self.multiplier

POLY_READ_CONVERSION

Adds a polynomial conversion factor to the current telemetry item

The conversion factor is applied to raw value in the telemetry packet before it is displayed to the user. The user still has the ability to see the raw unconverted value in a details dialog.

Parameter	Description	Required
C0	Coefficient	True
Cx	Additional coefficient values for the conversion. Any order polynomial conversion may be used so the value of 'x' will vary with the order of the polynomial. Note that larger order polynomials take longer to process than shorter order polynomials, but are sometimes more accurate.	False

Example Usage:

POLY_READ_CONVERSION 10 0.5 0.25

SEG_POLY_READ_CONVERSION

Adds a segmented polynomial conversion factor to the current telemetry item

This conversion factor is applied to the raw value in the telemetry packet before it is displayed to the user. The user still has the ability to see the raw unconverted value in a details dialog.

Parameter	Description	Required
Lower Bound	Defines the lower bound of the range of values that this segmented polynomial applies to. Is ignored for the segment with the smallest lower bound.	True
C0	Coefficient	True
Cx	Additional coefficient values for the conversion. Any order polynomial conversion may be used so the value of 'x' will vary with the order of the polynomial. Note that larger order polynomials take longer to process than shorter order polynomials, but are sometimes more accurate.	False

Example Usage:

SEG_POLY_READ_CONVERSION 0 10 0.5 0.25 # Apply the conversion to all values < 50
SEG_POLY_READ_CONVERSION 50 11 0.5 0.275 # Apply the conversion to all values >= 50 and < 100
SEG_POLY_READ_CONVERSION 100 12 0.5 0.3 # Apply the conversion to all values >= 100

GENERIC_READ_CONVERSION_START

Start a generic read conversion

Adds a generic conversion function to the current telemetry item. This conversion factor is applied to the raw value in the telemetry packet before it is displayed to the user. The user still has the ability to see the raw unconverted value in a details dialog. The conversion is specified as Ruby or Python code that receives two implied parameters. 'value' which is the raw value being read and 'packet' which is a reference to the telemetry packet class (Note, referencing the packet as 'myself' is still supported for backwards compatibility). The last line of code should return the converted value. The GENERIC_READ_CONVERSION_END keyword specifies that all lines of code for the conversion have been given.

warning

Generic conversions are not a good long term solution. Consider creating a conversion class and using READ_CONVERSION instead. READ_CONVERSION is easier to debug and has higher performance.

Parameter	Description	Required
Converted Type	Type of the converted value Valid Values: INT, UINT, FLOAT, STRING, BLOCK	False
Converted Bit Size	Bit size of converted value	False

Ruby Example:

APPEND_ITEM ITEM1 32 UINT
  GENERIC_READ_CONVERSION_START
    return (value * 1.5).to_i # Convert the value by a scale factor
  GENERIC_READ_CONVERSION_END

Python Example:

APPEND_ITEM ITEM1 32 UINT
  GENERIC_READ_CONVERSION_START
    return int(value * 1.5) # Convert the value by a scale factor
  GENERIC_READ_CONVERSION_END

GENERIC_READ_CONVERSION_END

Complete a generic read conversion

LIMITS

Defines a set of limits for a telemetry item

If limits are violated a message is printed in the Command and Telemetry Server to indicate an item went out of limits. Other tools also use this information to update displays with different colored telemetry items or other useful information. The concept of "limits sets" is defined to allow for different limits values in different environments. For example, you might want tighter or looser limits on telemetry if your environment changes such as during thermal vacuum testing.

Parameter	Description	Required
Limits Set	Name of the limits set. If you have no unique limits sets use the keyword DEFAULT.	True
Persistence	Number of consecutive times the telemetry item must be within a different limits range before changing limits state.	True
Initial State	Whether limits monitoring for this telemetry item is initially enabled or disabled. Note if you have multiple LIMITS items they should all have the same initial state. Valid Values: ENABLED, DISABLED	True
Red Low Limit	If the telemetry value is less than or equal to this value a Red Low condition will be detected	True
Yellow Low Limit	If the telemetry value is less than or equal to this value, but greater than the Red Low Limit, a Yellow Low condition will be detected	True
Yellow High Limit	If the telemetry value is greater than or equal to this value, but less than the Red High Limit, a Yellow High condition will be detected	True
Red High Limit	If the telemetry value is greater than or equal to this value a Red High condition will be detected	True
Green Low Limit	Setting the Green Low and Green High limits defines an "operational limit" which is colored blue by OpenC3. This allows for a distinct desired operational range which is narrower than the green safety limit. If the telemetry value is greater than or equal to this value, but less than the Green High Limit, a Blue operational condition will be detected.	False
Green High Limit	Setting the Green Low and Green High limits defines an "operational limit" which is colored blue by OpenC3. This allows for a distinct desired operational range which is narrower than the green safety limit. If the telemetry value is less than or equal to this value, but greater than the Green Low Limit, a Blue operational condition will be detected.	False

Example Usage:

LIMITS DEFAULT 3 ENABLED -80.0 -70.0 60.0 80.0 -20.0 20.0
LIMITS TVAC 3 ENABLED -80.0 -30.0 30.0 80.0

LIMITS_RESPONSE

Defines a response class that is called when the limits state of the current item changes

Parameter	Description	Required
Response Class Filename	Name of the Ruby or Python file which implements the limits response. This file should be in the target's lib directory.	True
Response Specific Options	Variable length number of options that will be passed to the class constructor	False

Ruby Example:

LIMITS_RESPONSE example_limits_response.rb 10

Python Example:

LIMITS_RESPONSE example_limits_response.py 10

APPEND_ITEM

Defines a telemetry item in the current telemetry packet

Parameter	Description	Required
Name	Name of the telemety item. Must be unique within the packet.	True
Bit Size	Bit size of this telemetry item. Zero or Negative values may be used to indicate that a string fills the packet up to the offset from the end of the packet specified by this value. If Bit Offset is 0 and Bit Size is 0 then this is a derived parameter and the Data Type must be set to 'DERIVED'.	True
Data Type	Data Type of this telemetry item Valid Values: INT, UINT, FLOAT, STRING, BLOCK, DERIVED	True
Description	Description for this telemetry item which must be enclosed with quotes	False
Endianness	Indicates if the item is to be interpreted in Big Endian or Little Endian format. See guide on Little Endian Bitfields. Valid Values: BIG_ENDIAN, LITTLE_ENDIAN	False

Example Usage:

APPEND_ITEM PKTID 16 UINT "Packet ID"

ID_ITEM

Defines a telemetry item in the current telemetry packet. Note, packets defined without one or more ID_ITEMs are "catch-all" packets which will match all incoming data. Normally this is the job of the UNKNOWN packet.

Parameter	Description	Required
Name	Name of the telemety item. Must be unique within the packet.	True
Bit Offset	Bit offset into the telemetry packet of the Most Significant Bit of this item. May be negative to indicate on offset from the end of the packet.	True
Bit Size	Bit size of this telemetry item. Zero or Negative values may be used to indicate that a string fills the packet up to the offset from the end of the packet specified by this value.	True
Data Type	Data Type of this telemetry item Valid Values: INT, UINT, FLOAT, STRING, BLOCK	True
ID Value	The value of this telemetry item that uniquely identifies this telemetry packet	True
Description	Description for this telemetry item which must be enclosed with quotes	False
Endianness	Indicates if the item is to be interpreted in Big Endian or Little Endian format. See guide on Little Endian Bitfields. Valid Values: BIG_ENDIAN, LITTLE_ENDIAN	False

Example Usage:

ID_ITEM PKTID 112 16 UINT 1 "Packet ID which must be 1"

APPEND_ID_ITEM

Defines a telemetry item in the current telemetry packet

Parameter	Description	Required
Name	Name of the telemety item. Must be unique within the packet.	True
Bit Size	Bit size of this telemetry item. Zero or Negative values may be used to indicate that a string fills the packet up to the offset from the end of the packet specified by this value.	True
Data Type	Data Type of this telemetry item Valid Values: INT, UINT, FLOAT, STRING, BLOCK	True
ID Value	The value of this telemetry item that uniquely identifies this telemetry packet	True
Description	Description for this telemetry item which must be enclosed with quotes	False
Endianness	Indicates if the item is to be interpreted in Big Endian or Little Endian format. See guide on Little Endian Bitfields. Valid Values: BIG_ENDIAN, LITTLE_ENDIAN	False

Example Usage:

APPEND_ID_ITEM PKTID 16 UINT 1 "Packet ID which must be 1"

ARRAY_ITEM

Defines a telemetry item in the current telemetry packet that is an array

Parameter	Description	Required
Name	Name of the telemety item. Must be unique within the packet.	True
Bit Offset	Bit offset into the telemetry packet of the Most Significant Bit of this item. May be negative to indicate on offset from the end of the packet. Always use a bit offset of 0 for derived item.	True
Item Bit Size	Bit size of each array item	True
Item Data Type	Data Type of each array item Valid Values: INT, UINT, FLOAT, STRING, BLOCK, DERIVED	True
Array Bit Size	Total Bit Size of the Array. Zero or Negative values may be used to indicate the array fills the packet up to the offset from the end of the packet specified by this value.	True
Description	Description which must be enclosed with quotes	False
Endianness	Indicates if the data is to be sent in Big Endian or Little Endian format Valid Values: BIG_ENDIAN, LITTLE_ENDIAN	False

Example Usage:

ARRAY_ITEM ARRAY 64 32 FLOAT 320 "Array of 10 floats"

APPEND_ARRAY_ITEM

Defines a telemetry item in the current telemetry packet that is an array

Parameter	Description	Required
Name	Name of the telemety item. Must be unique within the packet.	True
Item Bit Size	Bit size of each array item	True
Item Data Type	Data Type of each array item Valid Values: INT, UINT, FLOAT, STRING, BLOCK, DERIVED	True
Array Bit Size	Total Bit Size of the Array. Zero or Negative values may be used to indicate the array fills the packet up to the offset from the end of the packet specified by this value.	True
Description	Description which must be enclosed with quotes	False
Endianness	Indicates if the data is to be sent in Big Endian or Little Endian format Valid Values: BIG_ENDIAN, LITTLE_ENDIAN	False

Example Usage:

APPEND_ARRAY_ITEM ARRAY 32 FLOAT 320 "Array of 10 floats"

SELECT_ITEM

Selects an existing telemetry item for editing

Must be used in conjunction with SELECT_TELEMETRY to first select the packet. Typically used to override generated values or make specific changes to telemetry that only affect a particular instance of a target used multiple times.

Parameter	Description	Required
Item	Name of the item to select for modification	True

Example Usage:

SELECT_TELEMETRY INST HEALTH_STATUS
  SELECT_ITEM TEMP1
    # Define limits for this item, overrides or replaces any existing
    LIMITS DEFAULT 3 ENABLED -90.0 -80.0 80.0 90.0 -20.0 20.0

DELETE_ITEM

(Since 4.4.1)

Delete an existing telemetry item from the packet definition

Deleting an item from the packet definition does not remove the defined space for that item. Thus unless you redefine a new item, there will be a "hole" in the packet where the data is not accessible. You can use SELECT_TELEMETRY and then ITEM to define a new item.

Parameter	Description	Required
Item	Name of the item to delete	True

Example Usage:

SELECT_TELEMETRY INST HEALTH_STATUS
  DELETE_ITEM TEMP4

META

Stores metadata for the current telemetry packet

Meta data is user specific data that can be used by custom tools for various purposes. One example is to store additional information needed to generate source code header files.

Parameter	Description	Required
Meta Name	Name of the metadata to store	True
Meta Values	One or more values to be stored for this Meta Name	False

Example Usage:

META FSW_TYPE "struct tlm_packet"

PROCESSOR

Defines a processor class that executes code every time a packet is received

Parameter	Description	Required
Processor Name	The name of the processor	True
Processor Class Filename	Name of the Ruby or Python file which implements the processor. This file should be in the target's lib directory.	True
Processor Specific Options	Variable length number of options that will be passed to the class constructor.	False

Ruby Example:

PROCESSOR TEMP1HIGH watermark_processor.rb TEMP1

Python Example:

PROCESSOR TEMP1HIGH watermark_processor.py TEMP1

ALLOW_SHORT

Process telemetry packets which are less than their defined length

Allows the telemetry packet to be received with a data portion that is smaller than the defined size without warnings. Any extra space in the packet will be filled in with zeros by OpenC3.

HIDDEN

Hides this telemetry packet from all the OpenC3 tools

This packet will not appear in Packet Viewer, Telemetry Grapher and Handbook Creator. It also hides this telemetry from appearing in the Script Runner popup helper when writing scripts. The telemetry still exists in the system and can received and checked by scripts.

ACCESSOR

(Since 5.0.10)

Defines the class used to read and write raw values from the packet

Defines the class that is used too read raw values from the packet. Defaults to BinaryAccessor. For more information see Accessors.

Parameter	Description	Required
Accessor Class Name	The name of the accessor class	True

TEMPLATE

(Since 5.0.10)

Defines a template string used to pull telemetry values from a string buffer

Parameter	Description	Required
Template	The template string which should be enclosed in quotes	True

TEMPLATE_FILE

(Since 5.0.10)

Defines a template file used to pull telemetry values from a string buffer

Parameter	Description	Required
Template File Path	The relative path to the template file. Filename should generally start with an underscore.	True

IGNORE_OVERLAP

(Since 5.16.0)

Ignores any packet items which overlap

Packet items which overlap normally generate a warning unless each individual item has the OVERLAP keyword. This ignores overlaps across the entire packet.

VIRTUAL

(Since 5.18.0)

Marks this packet as virtual and not participating in identification

Used for packet definitions that can be used as structures for items with a given packet.

SELECT_TELEMETRY

Selects an existing telemetry packet for editing

Typically used in a separate configuration file from where the original telemetry is defined to override or add to the existing telemetry definition. Must be used in conjunction with SELECT_ITEM to change an individual item.

Parameter	Description	Required
Target Name	Name of the target this telemetry packet is associated with	True
Packet Name	Name of the telemetry packet to select	True

Example Usage:

SELECT_TELEMETRY INST HEALTH_STATUS
  SELECT_ITEM TEMP1
    # Define limits for this item, overrides or replaces any existing
    LIMITS DEFAULT 3 ENABLED -90.0 -80.0 80.0 90.0 -20.0 20.0

LIMITS_GROUP

Defines a group of related limits Items

Limits groups contain telemetry items that can be enabled and disabled together. It can be used to group related limits as a subsystem that can be enabled or disabled as that particular subsystem is powered (for example). To enable a group call the enable_limits_group("NAME") method in Script Runner. To disable a group call the disable_limits_group("NAME") in Script Runner. Items can belong to multiple groups but the last enabled or disabled group "wins". For example, if an item belongs to GROUP1 and GROUP2 and you first enable GROUP1 and then disable GROUP2 the item will be disabled. If you then enable GROUP1 again it will be enabled.

Parameter	Description	Required
Group Name	Name of the limits group	True

LIMITS_GROUP_ITEM

Adds the specified telemetry item to the last defined LIMITS_GROUP

Limits group information is typically kept in a separate configuration file in the config/TARGET/cmd_tlm folder named limits_groups.txt.

Parameter	Description	Required
Target Name	Name of the target	True
Packet Name	Name of the packet	True
Item Name	Name of the telemetry item to add to the group	True

Example Usage:

LIMITS_GROUP SUBSYSTEM
  LIMITS_GROUP_ITEM INST HEALTH_STATUS TEMP1
  LIMITS_GROUP_ITEM INST HEALTH_STATUS TEMP2
  LIMITS_GROUP_ITEM INST HEALTH_STATUS TEMP3

Example File

Example File: TARGET/cmd_tlm/tlm.txt

TELEMETRY TARGET HS BIG_ENDIAN "Health and Status for My Target"
  ITEM CCSDSVER 0 3 UINT "CCSDS PACKET VERSION NUMBER (SEE CCSDS 133.0-B-1)"
  ITEM CCSDSTYPE 3 1 UINT "CCSDS PACKET TYPE (COMMAND OR TELEMETRY)"
    STATE TLM 0
    STATE CMD 1
  ITEM CCSDSSHF 4 1 UINT "CCSDS SECONDARY HEADER FLAG"
    STATE FALSE 0
    STATE TRUE 1
  ID_ITEM CCSDSAPID 5 11 UINT 102 "CCSDS APPLICATION PROCESS ID"
  ITEM CCSDSSEQFLAGS 16 2 UINT "CCSDS SEQUENCE FLAGS"
    STATE FIRST 0
    STATE CONT 1
    STATE LAST 2
    STATE NOGROUP 3
  ITEM CCSDSSEQCNT 18 14 UINT "CCSDS PACKET SEQUENCE COUNT"
  ITEM CCSDSLENGTH 32 16 UINT "CCSDS PACKET DATA LENGTH"
  ITEM CCSDSDAY 48 16 UINT "DAYS SINCE EPOCH (JANUARY 1ST, 1958, MIDNIGHT)"
  ITEM CCSDSMSOD 64 32 UINT "MILLISECONDS OF DAY (0 - 86399999)"
  ITEM CCSDSUSOMS 96 16 UINT "MICROSECONDS OF MILLISECOND (0-999)"
  ITEM ANGLEDEG 112 16 INT "Instrument Angle in Degrees"
    POLY_READ_CONVERSION 0 57.295
  ITEM MODE 128 8 UINT "Instrument Mode"
    STATE NORMAL 0 GREEN
    STATE DIAG 1 YELLOW
  ITEM TIMESECONDS 0 0 DERIVED "DERIVED TIME SINCE EPOCH IN SECONDS"
    GENERIC_READ_CONVERSION_START FLOAT 32
      ((packet.read('ccsdsday') * 86400.0) + (packet.read('ccsdsmsod') / 1000.0) + (packet.read('ccsdsusoms') / 1000000.0)  )
    GENERIC_READ_CONVERSION_END
  ITEM TIMEFORMATTED 0 0 DERIVED "DERIVED TIME SINCE EPOCH AS A FORMATTED STRING"
    GENERIC_READ_CONVERSION_START STRING 216
      time = Time.ccsds2mdy(packet.read('ccsdsday'), packet.read('ccsdsmsod'), packet.read('ccsdsusoms'))
      sprintf('%04u/%02u/%02u %02u:%02u:%02u.%06u', time[0], time[1], time[2], time[3], time[4], time[5], time[6])
    GENERIC_READ_CONVERSION_END