Rainer, There are a few approaches that would solve you problem. You could use the *StdCalibrate* service to simply assign your existing sensor data to a another field or if you needed to do something beyond the limited capabilities of the *StdCalibrate* service could write your own custom service to do what you need. The other alternative for data that comes from a driver with a sensor/field map is to simply change the sensor/field map so that the driver places the data concerned into the field you wish to use right from the start.
Please note, in the following examples I have used *extraTemp2* as the field to be recycled, this is a poor choice for a couple of reasons; firstly it is quite possible a GW1000 user would want to use *extraTemp2* for additional temperature sensors. Secondly, *extraTemp2* normally holds temperature data and we will now be storing non-temperature data in the field, better to use a field that stores the same type of data if possible (more precisely the same unit type, eg pressure, concentration, speed etc). In this case the use of WeeWX field *no2* or *pm1_0* may have been better. In your case I would customise the GW1000 driver field map. In this example let's assume you want to store your second PM2.5 sensor in WeeWX field *extraTemp2* and your GW1000 is emitting data from your second PM2.5 sensor in field *pm25_2*. In order to change the sensor map for the GW1000 we need to know two things, what field we are mapping from and what field we are mapping to. We know we are mapping to *extraTemp2* but we are not actually mapping from *pm25_2*, we are actually mapping from GW1000 internal field *pm252* (in many cases the internal GW1000 field is the same as the field name that appears in the loop packet but some are different for a number of reasons that I will not go into here). You will find details of the GW1000 driver default field map and internal field names in the GW1000 driver Field map wiki entry <https://github.com/gjr80/weewx-gw1000/wiki/Field-map>. If we want to alter just a small number of field map entries we can do so using the *[[field_map_extensions]]* stanza (if we wanted to re-define the entire field map we would use the *[[field_map]]* stanza) under *[GW1000]* in *weewx.conf* as follows: [GW1000] .... [[field_map_extensions]] extraTemp2 = pm252 There is one other step you will need to follow and that is to ensure that your 'recycled' field is set to the appropriate unit group. All fields in the WeeWX database schema are assigned to a unit group, that way WeeWX knows the data in, for example, WeeWX field *outTemp* is a temperature and not a pressure. In this case, we have used *extraTemp2* and by default WeeWX will treat any data in that field as temperature. We need to change that, this can be done in a number of ways but the simplest is to simply assign the appropriate unit group in the file *extensions.py *( *extensions.py* is located in */home/weewx/bin/user* or */usr/share/weewx/user* depending on how you installed WeeWX). In this case edit *extensions.py* and add the following lines to the bottom of the file: import weewx.units weewx.units.obs_group_dict['extraTemp2'] = 'group_concentration' In this case we have re-assigned field *extraTemp2* to belong to the unit group *group_concentration* (the WeeWX unit group used for concentrations). A similar but slightly different approach is covered in the Assigning a unit group <http://weewx.com/docs/customizing.htm#Assigning_a_unit_group> section in the Customization Guide <http://weewx.com/docs/customizing.htm>. Note the *extensions.py* modification was necessary because the destination field and and source data are of different unit groups, if they were the same then there is no need to change any unit groups. Save *weewx.conf* and *extensions.py* and restart WeeWX and the PM2.5 data from the second sensor will appear in field *extraTemp2* in loop packets emitted by the GW1000 driver. WeeWX will accumulate this loop data and *extraTemp2* will be included in archive records synthesised by WeeWX. You can then use *extraTemp2* in tags in WeeWX report templates. That covers the GW1000 field map approach. For the sake of completeness I will cover the *StdCalibrate* approach as well. To achieve the same result with the *StdCalibrate* service we add an entry under *[StdCalibrate] [[Corrections]]* in *weewx.conf*. In this case we would use: [StdCalibrate] .... [[Corrections]] .... extraTemp2 = pm25_2 Note that in this case we used field *pm25_2* as we are actually using the field from the loop packet and archive record rather than an internal field in the GW1000 driver. You would also need to make the same addition to *extensions.py* to deal with the units as was done with the GW1000 field map example above. Gary On Tuesday, 22 December 2020 at 14:44:50 UTC+10 lang....@googlemail.com wrote: > I have several sensors which in my observation do not have a counterpart > in the extended weewx database schema. > > But I still want them stored in the weewx database and have them and their > history displayed in the web interface under http://IP-address/weewx > > E.g. there seems to be only one (1) field for PM2.5 sensors, however I've > got two of the WH41 sensors and the GW1000 provides values for both. > I already managed to get one of them displayed in the current conditions > and daily chart page (and also making them show on the weekly, monthly, > yearly pages is now just a matter a > > I suspect that the second simply gets lost as there is no standard field > in the database to accommodate them. > > In a post in the WXforum Gary mentions several approaches how to store > ("archive" in weewx terminology) such sensor values ("observations") in the > weewx database. > https://www.wxforum.net/index.php?topic=34857.0 > > "So in summary the following approaches (in order of complexity) are > available: > 1. utilise existing but unused database fields > 2. use a customised database schema by adding to the existing schema > 3. use a customised database schema by creating a new schema > 4. use a second database" > > I want to go for number 1 but didn't find instructions how (and where) to > do so. > > Can anyone provide guidance here please ? > > Thanks and regards > > Rainer > -- You received this message because you are subscribed to the Google Groups "weewx-user" group. 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