Adding PR6 pulse counter to V200 water meter and EmonPi

[Cobalt]

Hi all,

I just got a new water meter installed which I’d like to add to my EmonPi. It’s an Elster V200 and I’ll most likely order the Elster PR6 1:1 pulse counter.

Two questions:

• has anyone done this before with a V200, PR6 and EmonPi?
• does anyone have any lessons learned from connecting the PR6?

I’ve seen the posts between @glyn.hudson and @pb66 however I haven’t found a resolution on the forums.

Looking at the fitting instructions on the PR6, there are 6 wires. I’d probably only need the CH2P and GND but do I need to use a pullup resistor in there for the EmonPi?

I’ll add a RJ45 Expander as I’m already using the RJ45 port for the Energy Pulse Counter. The link to the pinout on this page redirects to the frontpage. Is there an RJ45 pinout diagram I can use to connect the PR6?

Thx for your help…

[Robert.Wall]

@Cobalt

I’m already using the RJ45 port for the Energy Pulse Counter.

You can’t have two pulse inputs to the emon part of the emonPi. It’s simply not capable of it. I take it that was your plan?

You can, I believe, wire a pulse input to the Raspberry Pi itself, but there’s no provision for that in the standard SD card software. I can’t tell you how to wire it nor what you need in the way of software, that’s outside my area of expertise.

But you can wire the (water) pulse counter instead of the optical one, or possibly a lot more conveniently, you could wire the water pulses into an emonTH to read the pulses and send the count by radio to your emonPi.

[Cobalt]

Thx for the quick reply. Yes, that was the plan…

The easy solution was indeed to use the EmonTH and pulse sensor but as everything is in the same closet I was hoping it could be solved by using the EmonPi itself.

I found this post, I’ll try and see if I can make a 1 sensor version instead of a 12 input

[Robert.Wall]

If you do that, how are you going to get the count into the Pi? Remember, the serial input is already in use by the “emon” front end that gives you the analogue energy monitoring and the energy pulse input. This is why you need to use the Pi’s GPIO and a script or a service running in the Pi itself, passing the data to emonHub or emonCMS directly.

And this is what I had at the back of my mind that does just that, but didn’t find earlier:

Directly connecting to Optical Pulse Counter with RPi?

You can indeed use the optical pulse counter directly with a Pi. I use a python script with 2 pulse counters, their data pins are connected to gpio pins 13 and 15, and are powered by pins 9 and 17 so that a simple 1x5 header socket could be plugged directly on the gpio pins (9-17 odds). Rather than chop the rj45’s off the pulse counters I use a surface mount double rj45 socket with just 4 wires between the sockets and the Pi gpio. The pulse counters are just a logic level switch, it just tra…

Coming back to the original question, as your meter uses an active pull-down, you will need a pull-up resistor to the appropriate voltage to provide a solid logic ‘high’ to the input pin.

And the pinout: emonTx3 User Guide — OpenEnergyMonitor 0.0.1 documentation

You can of course parallel the one-wire temperature sensors, but you can’t do that with the pulse input, which is a logical voltage level input.

[pearsonhenry2 (Henry Pearson)]

Hi All.

I’ve just installed an emonPi measuring my electricity and Solar. I’m now looking at adding my gas and water.
I have a V200 water meter and planning on getting a PR6 pulse counter wired into an emonTH.

Can anyone advise on the pin wiring required - will a resistor be needed? From the diagram from @Cobalt I would use CH2P and GND - does this then need a resistor going into the emonTH?

[Robert.Wall]

Welcome, Henry, to the OEM forum.

I take it you’re referring to the diagram in post no.1 above.

You’re correct, you need to connect the meter’s GND to the emonTH GND (pin 3 on the screw terminals) and the meter’s CH2P to the emonTH Pulse input (pin 4). You should not need an external pull-up resistor because the internal pull-up is enabled in the software. (Line 233 in the sketch if you want to look.)