I’ve set up a 3phase emonvs connected to 10m Cat6 cable to the EmonPi2 by the incoming meter
On startup, the display stays on “Starting” . 5 minutes later its still on “startng”!.
Any ideas?
So you have 10 m of cable between the emonVs and the emonPi2?
Does it start successfully if you use the supplied short cable? If it does, it’s likely your problem is you’re dropping too much voltage on the 5 V supply from the emonVs to the emonPi. What is the CSA of your particular CAT6 cable - given this, and knowing a RPi4 can draw about 1.8 A, it’s easy enough to work out what the 5 V will end up as when it gets to the RPi.
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It appears your CAT6 cable can be anywhere between 26 AWG and 22 AWG. The voltage drops for 2 × 10 m at 1.8 A for those wire gauges are 9.6 V and 3.8 V. Clearly, your Pi isn’t going to be able to start when it stands to have almost no voltage as it tries to draw current to start up, so it’s quit, and only the relatively low current “emon” front end (which is where the “Starting…” message comes from) and the display is working.
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Why does the emonPi need to be 10 m away, can you not use the Ethernet cable for data (only, no power) between the emonPi and your router and avoid using relatively thin cores for a relatively heavy current?
Doh!, Of course. It’s me not thinking it through. The EmonPi2 started fine next to the EmonVS. Sorry shouldve done that first.
The nearest 3 phase distribution board is 10m from the meter. The supply is split just after the meter going to 2 seperate distribulation boards so I need the CT’s near the meter, so I thought I’d just run a 10m ethernet cable I had around!. I’ll arrange to replace it with a 5 core cable.
Thanks for the quick reply!
What’s this for - the 3-phase mains to the emonVs? Remember you need a 3- or 4-pole linked circuit breaker with a low current rating to protect it. I don’t know the inrush current for the emonVs, my guess is a 1 A mcb would be OK, a 6 A to protect 1.5 mm² cable would be more than plenty.
As the c.t’s are voltage-output type, you could alternatively use your Ethernet cable to extend the c.t. cables (making sure of course you use a twisted pair per c.t. - blue + blue/white etc), but the lack of an overall screen could be an issue.
Thankyou! Sorry for the slow reply.
5 Core is my laymans terms for the cable needed - L1, L2, L3, N , Earth - 5 wires.
That has given a feeds from the meter which gives me a feed showing amount of electric imported and exported.
The next challenge is the Solar array is on another building 50m away, feeding into the distribution panel in that building. There are metal lined walls inbetween.
Is it best to extend the CT cables using screened cable from the inverter to the EmonPi2? Bearing in mind it is 3 phase, so that would be 3 CT’s.
Or would a EmonTx connected by a USB C cable work better.
Thankyou
Alastair
What is “better”? You face a trade-off:
If you put the c.t’s on the end of a long cable, the power you calculate for the PV will be affected by the mains voltage drop between where the emonVs measures the voltage and the point where you measure the current. Is this acceptable to you? This is the more economical solution.
If you want to avoid the inaccuracy this introduces, you’ll need another emonVs and emonTx (when available) at the point where the PV feeds into your power distribution network. But you can’t use USB over a distance of 50 m, you’ll need either to go to and from something like RS485 at each end, or USB to Ethernet at the emonTx end and straight into the emonPi at the other end. I’m assuming you know or think that neither the ISM band 433 MHz radio nor Wi-Fi (if/when available with the emonTx5) will work between the two.
Or you could have another emonPi + emonVs looking after the PV, communicating via Ethernet with the other one.
Thankyou.
I’m assuming you know or think that neither the ISM band 433 MHz radio
I don’t know, however in line of sight there would be 4 metal lined walls in-between, which in believe will disrupt the signal?
Or you could have another emonPi + emonVs looking after the PV, communicating via Ethernet with the other one.
I am using a Emonpi2 with 12 CT clamps so the ethernet port is not available…
Is USB to ethernet at both ends an option?
Thankyou
The only way would be to try. You know what your site looks like, all I know is what’s written here. From your comment, I wouldn’t pin too many hopes on it, so I think it’s best to rule it out.
That could be another option. Of course, Ethernet or Wi-Fi only needs to reach an access point or switch on the same LAN (or one that’s bridged), if that’s nearer or more convenient. At 50 m, you should be OK with Cat5 cable.