org.lsst.ccs.subsystem.shutter.plc

Class Tools

java.lang.Object

org.lsst.ccs.subsystem.shutter.plc.Tools

public class Tools
extends Object

Provides some small utility functions.

Author:

tether

Field Summary

Fields

Modifier and Type	Field and Description
static long	UTC_SECONDS_YEAR_2000

Constructor Summary

Constructors

Constructor and Description
Tools()

Method Summary

Modifier and Type	Method and Description
static Duration	fromDcDuration(long dcNanos) Converts EtherCat time interval, assumed to be the difference of two DC time values, into a Duration.
static org.lsst.ccs.utilities.taitime.CCSTimeStamp	fromDcTime64(long dctime64, int dtai) Converts a TwinCAT absolute timestamp to a CCSTimeStamp.
static boolean	getBoolean(ByteBuffer data) Gets a PLC BOOL value from a byte buffer and converts it to a boolean value.
static void	main(String[] args)
static void	putBoolean(ByteBuffer data, boolean b) Appends to a byte buffer the PLC BOOL value equivalent to a Java boolean.
static long	toDcDuration(Duration interval) Reverses the transformation performed by toDcDuration(java.time.Duration).
static long	toDcTime64(org.lsst.ccs.utilities.taitime.CCSTimeStamp ccsTime) Converts a CCS timestamp to a T_DCTIME64 value.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

UTC_SECONDS_YEAR_2000

public static long UTC_SECONDS_YEAR_2000

Constructor Detail

Tools

public Tools()

Method Detail

getBoolean

public static boolean getBoolean(ByteBuffer data)

Gets a PLC BOOL value from a byte buffer and converts it to a boolean value.

Parameters:

data - Holds the data.

Returns:

The boolean value.

putBoolean

public static void putBoolean(ByteBuffer data,
                              boolean b)

Appends to a byte buffer the PLC BOOL value equivalent to a Java boolean.

Parameters:

data - Holds the data.

b - The boolean value to convert and append.

fromDcTime64

public static org.lsst.ccs.utilities.taitime.CCSTimeStamp fromDcTime64(long dctime64,
                                                                       int dtai)

Converts a TwinCAT absolute timestamp to a CCSTimeStamp. Absolute timestamps are produced by the PLC function F_ConvTcToExtTime64() and are expressed as 64-bit unsigned integers of type T_DCTIME64, a count of nanoseconds.

T_DCTIME64 timestamps are like TAI64N timestamps but have a couple of peculiarities. A value of zero nanoseconds denotes 0 hours on Jan 1 2000 UTC, not any of the standard epochs. Even so, the timestamp has the full, current count of leap seconds even though many of those occurred before the year 2000. Therefore producing a true TAI64N value must be done with care in order to avoid double-counting those earlier leap seconds.

Parameters:

dctime64 - The T_DCTIME64 value.

dtai - What the observatory calls the the number of seconds that a "TAI Instant" is ahead of a standard Instant. It's effectively the current number of leap seconds, 37 as of November 2023.

Returns:

The CCS timestamp.

toDcTime64

public static long toDcTime64(org.lsst.ccs.utilities.taitime.CCSTimeStamp ccsTime)

Converts a CCS timestamp to a T_DCTIME64 value. Essentially the inverse of fromDcTime64(long, int) except that the DTAI value is not supplied. It has to be calculated from the CCS timestamp itself since we need the value of DTAI as it was when the timestamp was created, not the current value.

Parameters:

ccsTime - The CCS timestamp.

Returns:

The absolute T_DCTIME64 timestamp, which should be treated as unsigned.

fromDcDuration

public static Duration fromDcDuration(long dcNanos)

Converts EtherCat time interval, assumed to be the difference of two DC time values, into a Duration.

Parameters:

dcNanos - The DC time difference, a count of nanoseconds.

Returns:

The Duration value.

toDcDuration

public static long toDcDuration(Duration interval)

Reverses the transformation performed by toDcDuration(java.time.Duration).

Parameters:

interval - The time interval to convert.

Returns:

The count of nanoseconds.

main

public static void main(String[] args)