Modbus - Real-Time Clock Bricklet¶

Basic Functions¶

BrickletRealTimeClock.set_date_time¶

Function ID:	1
Request:	year – Type: uint16, Range: [2000 to 2099] month – Type: uint8, Range: [1 to 12] day – Type: uint8, Range: [1 to 31] hour – Type: uint8, Range: [0 to 23] minute – Type: uint8, Range: [0 to 59] second – Type: uint8, Range: [0 to 59] centisecond – Type: uint8, Range: [0 to 99] weekday – Type: uint8, Range: See meanings
Response:	no response

Sets the current date (including weekday) and the current time.

If the backup battery is installed then the real-time clock keeps date and time even if the Bricklet is not powered by a Brick.

The real-time clock handles leap year and inserts the 29th of February accordingly. But leap seconds, time zones and daylight saving time are not handled.

The following meanings are defined for the elements of this function:

For weekday:

• 1 = Monday
• 2 = Tuesday
• 3 = Wednesday
• 4 = Thursday
• 5 = Friday
• 6 = Saturday
• 7 = Sunday

BrickletRealTimeClock.get_date_time¶

Function ID:	2
Request:	empty payload
Response:	year – Type: uint16, Range: [2000 to 2099] month – Type: uint8, Range: [1 to 12] day – Type: uint8, Range: [1 to 31] hour – Type: uint8, Range: [0 to 23] minute – Type: uint8, Range: [0 to 59] second – Type: uint8, Range: [0 to 59] centisecond – Type: uint8, Range: [0 to 99] weekday – Type: uint8, Range: See meanings

Returns the current date (including weekday) and the current time of the real-time clock.

The following meanings are defined for the elements of this function:

For weekday:

• 1 = Monday
• 2 = Tuesday
• 3 = Wednesday
• 4 = Thursday
• 5 = Friday
• 6 = Saturday
• 7 = Sunday

BrickletRealTimeClock.get_timestamp¶

Function ID:	3
Request:	empty payload
Response:	timestamp – Type: int64, Unit: 1 ms, Range: [-263 to 263 - 1]

Returns the current date and the time of the real-time clock. The timestamp has an effective resolution of hundredths of a second and is an offset to 2000-01-01 00:00:00.000.

Advanced Functions¶

BrickletRealTimeClock.set_offset¶

Function ID:	4
Request:	offset – Type: int8, Unit: 217/100 ppm, Range: [-128 to 127]
Response:	no response

Sets the offset the real-time clock should compensate for in 2.17 ppm steps between -277.76 ppm (-128) and +275.59 ppm (127).

The real-time clock time can deviate from the actual time due to the frequency deviation of its 32.768 kHz crystal. Even without compensation (factory default) the resulting time deviation should be at most ±20 ppm (±52.6 seconds per month).

This deviation can be calculated by comparing the same duration measured by the real-time clock (rtc_duration) an accurate reference clock (ref_duration).

For best results the configured offset should be set to 0 ppm first and then a duration of at least 6 hours should be measured.

The new offset (new_offset) can be calculated from the currently configured offset (current_offset) and the measured durations as follow:

new_offset = current_offset - round(1000000 * (rtc_duration - ref_duration) / rtc_duration / 2.17)

If you want to calculate the offset, then we recommend using the calibration dialog in Brick Viewer, instead of doing it manually.

The offset is saved in the EEPROM of the Bricklet and only needs to be configured once.

BrickletRealTimeClock.get_offset¶

Function ID:	5
Request:	empty payload
Response:	offset – Type: int8, Unit: 217/100 ppm, Range: [-128 to 127]

Returns the offset as set by set_offset.

BrickletRealTimeClock.get_identity¶

Function ID:	255
Request:	empty payload
Response:	uid – Type: char[8] connected_uid – Type: char[8] position – Type: char, Range: ['a' to 'h', 'z'] hardware_version – Type: uint8[3] 0: major – Type: uint8, Range: [0 to 255] 1: minor – Type: uint8, Range: [0 to 255] 2: revision – Type: uint8, Range: [0 to 255] firmware_version – Type: uint8[3] 0: major – Type: uint8, Range: [0 to 255] 1: minor – Type: uint8, Range: [0 to 255] 2: revision – Type: uint8, Range: [0 to 255] device_identifier – Type: uint16, Range: [0 to 216 - 1]

Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be 'a', 'b', 'c', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). A Bricklet connected to an Isolator Bricklet is always at position 'z'.

The device identifier numbers can be found here. 

Callback Configuration Functions¶

BrickletRealTimeClock.set_date_time_callback_period¶

Function ID:	6
Request:	period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
Response:	no response

Sets the period with which the CALLBACK_DATE_TIME callback is triggered periodically. A value of 0 turns the callback off.

The CALLBACK_DATE_TIME Callback is only triggered if the date or time changed since the last triggering.

New in version 2.0.1 (Plugin).

BrickletRealTimeClock.get_date_time_callback_period¶

Function ID:	7
Request:	empty payload
Response:	period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by set_date_time_callback_period.

New in version 2.0.1 (Plugin).

BrickletRealTimeClock.set_alarm¶

Function ID:	8
Request:	month – Type: int8, Range: [-1, 1 to 12] with meanings day – Type: int8, Range: [-1, 1 to 31] with meanings hour – Type: int8, Range: [-1, 0 to 23] with meanings minute – Type: int8, Range: [-1, 0 to 59] with meanings second – Type: int8, Range: [-1, 0 to 59] with meanings weekday – Type: int8, Range: [-1, 1 to 7] with meanings interval – Type: int32, Unit: 1 s, Range: [-1, 1 to 231 - 1] with meanings
Response:	no response

Configures a repeatable alarm. The CALLBACK_ALARM callback is triggered if the current date and time matches the configured alarm.

Setting a parameter to -1 means that it should be disabled and doesn't take part in the match. Setting all parameters to -1 disables the alarm completely.

For example, to make the alarm trigger every day at 7:30 AM it can be configured as (-1, -1, 7, 30, -1, -1, -1). The hour is set to match 7 and the minute is set to match 30. The alarm is triggered if all enabled parameters match.

The interval has a special role. It allows to make the alarm reconfigure itself. This is useful if you need a repeated alarm that cannot be expressed by matching the current date and time. For example, to make the alarm trigger every 23 seconds it can be configured as (-1, -1, -1, -1, -1, -1, 23). Internally the Bricklet will take the current date and time, add 23 seconds to it and set the result as its alarm. The first alarm will be triggered 23 seconds after the call. Because the interval is not -1, the Bricklet will do the same again internally, take the current date and time, add 23 seconds to it and set that as its alarm. This results in a repeated alarm that triggers every 23 seconds.

The interval can also be used in combination with the other parameters. For example, configuring the alarm as (-1, -1, 7, 30, -1, -1, 300) results in an alarm that triggers every day at 7:30 AM and is then repeated every 5 minutes.

New in version 2.0.1 (Plugin).

The following meanings are defined for the elements of this function:

For month:

• -1 = Disabled

For day:

• -1 = Disabled

For hour:

• -1 = Disabled

For minute:

• -1 = Disabled

For second:

• -1 = Disabled

For weekday:

• -1 = Disabled

For interval:

• -1 = Disabled

BrickletRealTimeClock.get_alarm¶

Function ID:	9
Request:	empty payload
Response:	month – Type: int8, Range: [-1, 1 to 12] with meanings day – Type: int8, Range: [-1, 1 to 31] with meanings hour – Type: int8, Range: [-1, 0 to 23] with meanings minute – Type: int8, Range: [-1, 0 to 59] with meanings second – Type: int8, Range: [-1, 0 to 59] with meanings weekday – Type: int8, Range: [-1, 1 to 7] with meanings interval – Type: int32, Unit: 1 s, Range: [-1, 1 to 231 - 1] with meanings

Returns the alarm configuration as set by set_alarm.

New in version 2.0.1 (Plugin).

The following meanings are defined for the elements of this function:

For month:

• -1 = Disabled

For day:

• -1 = Disabled

For hour:

• -1 = Disabled

For minute:

• -1 = Disabled

For second:

• -1 = Disabled

For weekday:

• -1 = Disabled

For interval:

• -1 = Disabled

Callbacks¶

BrickletRealTimeClock.CALLBACK_DATE_TIME¶

Function ID:	10
Response:	year – Type: uint16, Range: [2000 to 2099] month – Type: uint8, Range: [1 to 12] day – Type: uint8, Range: [1 to 31] hour – Type: uint8, Range: [0 to 23] minute – Type: uint8, Range: [0 to 59] second – Type: uint8, Range: [0 to 59] centisecond – Type: uint8, Range: [0 to 99] weekday – Type: uint8, Range: See meanings timestamp – Type: int64, Unit: 1 ms, Range: [-263 to 263 - 1]

This callback is triggered periodically with the period that is set by set_date_time_callback_period. The response values are the same as for get_date_time and get_timestamp combined.

The CALLBACK_DATE_TIME callback is only triggered if the date or time changed since the last triggering.

New in version 2.0.1 (Plugin).

The following meanings are defined for the elements of this function:

For weekday:

• 1 = Monday
• 2 = Tuesday
• 3 = Wednesday
• 4 = Thursday
• 5 = Friday
• 6 = Saturday
• 7 = Sunday

BrickletRealTimeClock.CALLBACK_ALARM¶

Function ID:	11
Response:	year – Type: uint16, Range: [2000 to 2099] month – Type: uint8, Range: [1 to 12] day – Type: uint8, Range: [1 to 31] hour – Type: uint8, Range: [0 to 23] minute – Type: uint8, Range: [0 to 59] second – Type: uint8, Range: [0 to 59] centisecond – Type: uint8, Range: [0 to 99] weekday – Type: uint8, Range: See meanings timestamp – Type: int64, Unit: 1 ms, Range: [-263 to 263 - 1]

This callback is triggered every time the current date and time matches the configured alarm (see set_alarm). The response values are the same as for get_date_time and get_timestamp combined.

New in version 2.0.1 (Plugin).

The following meanings are defined for the elements of this function:

For weekday:

• 1 = Monday
• 2 = Tuesday
• 3 = Wednesday
• 4 = Thursday
• 5 = Friday
• 6 = Saturday
• 7 = Sunday