Instrumentation/Instrumentation: Update `timestamp` documentation
diff --git a/doc/instrumentation.rst b/doc/instrumentation.rst
index 91a2e64..76adf39 100644
--- a/doc/instrumentation.rst
+++ b/doc/instrumentation.rst
@@ -139,6 +139,14 @@
``<site>_<kind>`` (see :class:`InstrumentChannel`). The order of the columns
will be the same as the order of channels in ``Instrument.active_channels``.
+ If reporting timestamps, one channel must have a ``site`` named ``"timestamp"``
+ and a ``kind`` of a :class:`MeasurmentType` of an appropriate time unit which will
+ be used, if appropriate, during any post processing.
+
+ .. note:: Currently supported time units are seconds, milliseconds and
+ microseconds, other units can also be used if an appropriate
+ conversion is provided.
+
This returns a :class:`MeasurementCsv` instance associated with the outfile
that can be used to stream :class:`Measurement`\ s lists (similar to what is
returned by ``take_measurement()``.
@@ -211,27 +219,31 @@
defined measurement types are
-+-------------+---------+---------------+
-| name | units | category |
-+=============+=========+===============+
-| time | seconds | |
-+-------------+---------+---------------+
-| temperature | degrees | |
-+-------------+---------+---------------+
-| power | watts | power/energy |
-+-------------+---------+---------------+
-| voltage | volts | power/energy |
-+-------------+---------+---------------+
-| current | amps | power/energy |
-+-------------+---------+---------------+
-| energy | joules | power/energy |
-+-------------+---------+---------------+
-| tx | bytes | data transfer |
-+-------------+---------+---------------+
-| rx | bytes | data transfer |
-+-------------+---------+---------------+
-| tx/rx | bytes | data transfer |
-+-------------+---------+---------------+
++-------------+-------------+---------------+
+| name | units | category |
++=============+=============+===============+
+| time | seconds | |
++-------------+-------------+---------------+
+| time | microseconds| |
++-------------+-------------+---------------+
+| time | milliseconds| |
++-------------+-------------+---------------+
+| temperature | degrees | |
++-------------+-------------+---------------+
+| power | watts | power/energy |
++-------------+-------------+---------------+
+| voltage | volts | power/energy |
++-------------+-------------+---------------+
+| current | amps | power/energy |
++-------------+-------------+---------------+
+| energy | joules | power/energy |
++-------------+-------------+---------------+
+| tx | bytes | data transfer |
++-------------+-------------+---------------+
+| rx | bytes | data transfer |
++-------------+-------------+---------------+
+| tx/rx | bytes | data transfer |
++-------------+-------------+---------------+
.. instruments: