I have just noticed a bug where USA apparent power mode (when no AC-AC adapter is present), would return incorrect readings if used in the USA on 110V with USA mode enabled.
This has just been fixed with firmware V2.7.0. The emonTx was incorrectly still using 240V as Vrms when USA mode was enabled.
## emonTx V3.4 firmware change log:
- V3.4 05/01/21 Slow down DS18B20 conversion - required for new batch of RJ45 temp sensors
- V3.3 05/12/19 Fix RFM factory test
- V3.2 27/08/19 Add watchdog reset
- V3.1 25/05/18 Prompt to set 'Both CR & NL' on serial monitor.
- V3.0 16/01/18 Return zero reading when CT is disconnected and always sample from all CT's when powered by AC-AC (negate CT's required plugged in before startup)
- v2.9 30/03/17 Correct RMS voltage calc at startup when USA mode is enabled
- v2.8 27/02/17 Correct USA voltage to 120V
- v2.7 34/02/17 Fix USA apparent power readings (assuming 110VRMS when no AC-AC voltage sample adapter is present). Fix DIP switch nodeID config incorrect serial print if node ID has been set via EEPROM serial config and DIP switch.
- v2.6 31/10/16 Add RF config via serial & save to EEPROM feature. Allows RF settings (nodeID, freq, group) via serial
- v2.5 19/09/16 Increase baud 9600 > 115200 to emonesp compatibility
- v2.4 06/09/16 Update serial output to use CSV string pairs to work with emonESP e.g. 'ct1:100,ct2:329'
- v2.3 16/11/15 Change to unsigned long for pulse count and make default node ID 8 to avoid emonHub node decoder conflict & fix counting pulses faster than 110ms, strobed meter LED http://openenergymonitor.org/emon/node/11490
- v2.2 12/11/15 Remove debug timing serial print code
- v2.1 24/10/15 Improved timing so that packets are sent just under 10s, reducing resulting data gaps in feeds + default status code for no temp sensors of 3000 which reduces corrupt packets improving data reliability
- V2.0 30/09/15 Update number of samples 1480 > 1662 to improve sampling accurancy: 1662 samples take 300 mS, which equates to 15 cycles @ 50 Hz or 18 cycles @ 60 Hz.
- V1.9 25/08/15 Fix spurious pulse readings from RJ45 port when DS18B20 but no pulse counter is connected (enable internal pull-up)
- V1.8 - 18/06/15 Increase max pulse width to 110ms
- V1.7 - 12/06/15 Fix pulse count denounce issue & enable pulse count pulse temperature
show original
This bug is not an issue if using an AC-AC voltage sensor adapter to enable more accurate Real Power readings. Use of AC-AC adapter is highly recomenended.
Glyn,
The US system voltage is 120-0-120 (L-N-L)
240 Volts across both Lines, 120 Volts across either line and neutral.
The term 110 Volts is a hold-over from long ago.
But it’s the standard UK voltage for industrial portable tools (normally 55-0-55 to earth).
I read that in an article some time ago. But methinks there aren’t many UK power tools in use in the US.
I think you might be right, there. But 110 V is a common option in a power tools catalogue, and that’s probably where Glyn got 110 V instead of 120 V from. I always have to stop and think because 110 V is also common in control panels here.
Yup, that’s exactly where I got 110V from! Sorry, excuse my ignorance, I’ve never travelled to the US. I should have double checked.
Thanks for letting me know, I’ve corrected the sketch:
committed 02:17AM - 27 Feb 17 UTC
