# EmonTX is off by factor 2-3 **URL:** \ **Category:** emonTx\ **Created:** [30 November 2020 18:45 UTC](https://community.openenergymonitor.org/t/emontx-is-off-by-factor-2-3/16130 "2020-11-30T18:45:10Z")\ **Posts on this page:** 1\ **Showing post:** 12
**Author:** ![Robert.Wall](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/robert.wall/32/38246_2.png) [@Robert.Wall](https://community.openenergymonitor.org/u/Robert.Wall)\ **Post date:** [1 December 2020 12:03 UTC](https://community.openenergymonitor.org/t/emontx-is-off-by-factor-2-3/16130/12 "2020-12-01T12:03:48Z")
No current transformer should be left open-circuit. OK, it does have an internal protection diode, it should be OK, but you’re relying solely on that. The c.t. is so small that you’re unlikely to come to serious harm if the diode fails, but it’s still not something I’d do if there was another way. Why not turn the circuit off, twist a bit of copper wire around the plug (tip & sleeve, the ring is not used) and then you can put the power on, knowing that two things have to fail before you risk trouble. > [@Frans\_Akeson](#): > > I just have to dig out my old FTDI cable If you change the sketch to the 3-phase, you can recalibrate each channel and the voltage channel in the sketch, then you won’t need the 0.4 in emonHub because the correct values will come out of the emonTx. I suggest reading all the documentation and the notes inside the sketch first, so that you have an overall view of the procedure. > [@Update to 3-Phase PLL sketch](https://community.openenergymonitor.org/t/update-to-3-phase-pll-sketch/8610/21): > > An updated version of this sketch is attached here, correcting a minor problem with reading the configuration under certain conditions, and the two previous issues showed the wrong version number. MD5 Hashes: emonTx\_3Phase\_PLL\_V1.7.zip 067e98e295c9c2fcd14f31c784f5183a emonTx\_3Phase\_PLL.ino a1208c832e132b00087b69b593bc785b config.ino 678e7b2a2514a4068ab6d45bb576ae74 rfm.ino b830300d088943a64a4b54ee92e8e4a0 emonTx 3-phase PLL User Doc.pdf 00f2ccc51c5d4452e9d7a94ab6b9c547 [emonT…](https://community.openenergymonitor.org/uploads/short-url/mMXRoiQP65ysgjGqt7ReAGCs0MN.zip) --- _[View the full topic](https://community.openenergymonitor.org/t/emontx-is-off-by-factor-2-3/16130)._