node-red-contrib-dashboard-bar-chart-data

Bar-chart-data

This node transforms msg.payload, attaches (and stores) past values and build a message that could be linked to the ui_chart node configured as "bar chart". It can handle measurements (e.g. current power consumption) or meter readings (e.g. gas/water/energy meter count) and calculate the sum, min, max or average in a customizable time range. Works with multiple topics, too.

Properties :

Name

The name of this node

x-interval

1 bar per:

second

minute

quarter-hour

hour

day

year

x-size

How many bars should be displayed. Example: x-interval=hours, x-size=24 : 24 bars, each 1 hour. That means that the last 24 hours will be displayed

Unit

The unit of the payload, will be displayed in the bar-chart

Precision

Number of decimals

Meter reading

Set this to "True" if msg.payload is a meter reading, so that this node will use the difference of the current and last value.

True: msg.payload is meter reading, like the total energy, gas or water meter value or operating hours

False: msg.payload is a measurement, like power (watt), pressure or temperature

Aggregate by

sum: sum all values in x-interval

min: just display the smallest value in x-interval

max: just display the largest value in x-interval

avg: average value in x-interval

Prevent negative

For meter readings only: If the current meter reading is smaller than the last value, the difference between new and old value will be discarded and the new meter reading will be stored and become the current one. This is helpful if a new meter is installed or if the end of the meter is reached and the it starts from zero again. Without this switch the (negative) difference of new and old value will be calculated and displayed, what is not what you usually want when you want to display meter readings.

Screenshot

Clear

A message with the payload "clear" and the same topic like the sensor will reset the data for this specific sensor only. A message with the payload "clear" without a topic (empty string) will delete all data, so that the chart will be blank again.

Set (start) meter value

A message with the payload "set_meter_value 123.45" will set the (start) value for the topic to 123.45. The calculation of the difference between the new and the previous meter reading value will be skipped. You can use this when your old meter is replaced with a new one and the values begins from 0 (again).

Restore

If you put the output of this node to the input of this kind of node (via persist node), the data will be restored. This could be helpful to avoid getting a blank bar-chart after node-red has been restarted (reboot).

Logfiles to bar-chart

If msg.ts or msg.timestamp is given, this timestamp will be used for the reading instead of the current timestamp. You could use this feature to load (older) logfiles into bar-chart data. Caution: All values older than the given timestamp will be discarded => You have to start with the oldest value and will loose all values that are not inside the log files - except the current values are older than the ones from the logfile.

Additional output: Sum, Min, Max, Settings

This is included in the output message (and could be used to set chart title etc.):

The node settings (unit, x_interval, x_size, precision, is_meter_reading, agg_by) as json in msg.settings

The smallest value of all bars (min) in msg.min

The largest value of all bars (max) in msg.max

The sum of all bars in msg.sum

Sample Result

Sample Flow

[{"id":"307f07f.8b8c1f8","type":"bar-chart-data","z":"3b18da32.bba756","name":"bar-chart-data","x_interval":"seconds","x_size":"24","unit":"Liter","precision":"0","is_meter_reading":"False","agg_by":"sum","x":340,"y":140,"wires":[["11edb254.d31a6e","3e6bc8b7.f4bc88"]]},{"id":"11edb254.d31a6e","type":"ui_chart","z":"3b18da32.bba756","name":"","group":"c716d8f1.4bb848","order":3,"width":"12","height":"4","label":"Liter letzte {{msg.settings.x_size}} Sekunden {{msg.data_sum}}","chartType":"bar","legend":"false","xformat":"HH:mm:ss","interpolate":"linear","nodata":"","dot":false,"ymin":"","ymax":"","removeOlder":"30","removeOlderPoints":"","removeOlderUnit":"60","cutout":0,"useOneColor":true,"colors":["#1f77b4","#aec7e8","#ff7f0e","#2ca02c","#98df8a","#d62728","#ff9896","#9467bd","#c5b0d5"],"useOldStyle":false,"outputs":1,"x":510,"y":100,"wires":[[]]},{"id":"3e6bc8b7.f4bc88","type":"persist in","z":"3b18da32.bba756","name":"store","storageNode":"e0e7ea5c.056af8","x":510,"y":180,"wires":[]},{"id":"8343e961.cbf7e8","type":"inject","z":"3b18da32.bba756","name":"sensor","topic":"devices/homie-har/water/liter","payload":"1","payloadType":"num","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":130,"y":100,"wires":[["307f07f.8b8c1f8"]]},{"id":"29a85329.d6b03c","type":"persist out","z":"3b18da32.bba756","name":"store","storageNode":"e0e7ea5c.056af8","x":130,"y":180,"wires":[["307f07f.8b8c1f8"]]},{"id":"c716d8f1.4bb848","type":"ui_group","z":"","name":"bar-chart","tab":"957fd14a.a1277","disp":true,"width":"12","collapse":false},{"id":"e0e7ea5c.056af8","type":"persist-store","z":"","filename":"~/store.json","interval":"60"},{"id":"957fd14a.a1277","type":"ui_tab","z":"","name":"bar-chart","icon":"dashboard","disabled":false,"hidden":false}]