Hi Guys, The time has come for me to buy a RRampMeter, but I have a few questions. Its use as a portable voltage tester, producing accurate readings for DCC, is obvious. But, it appears that to get amperage readings, the meter has to be wired between the booster and the bus, i.e. a permanent installation.

How would I analyze a problem in an isolated section of track without buying a second RRampMeter?

Also, it appears each block or power district would require its own RRampMeter to measure amperage. Do I understand this correctly?

For a permanent installation, is the RRampMeter connected ahead of the circuit breaker or after? 

Finally, what is the advantage of the third version with the battery? I freely admit I am electronics challenged despite trying for 64 years so please explain why I would need to measure something below 7 volts on a small layout with two blocks. I use the NCE Powercab.

I need the meter, but your answers will help me decide which version to buy and how many I need. Thanks!............Bob

Voltage is like water pressure in a pipe, so we can simply measure the pressure anywhere. Current is like the movement of water in the pipe. We can't tell if it is moving unless it moves through our measuring device, and it may move differently in different parts of the plumbing (more flow in the bathtub pipe than in the sink pipe). Hence, you can use the RRampmeter to measure voltage anywhere, but it needs to be in series with the wire in which you want to measure the current. Voltage is the same everywhere on the layout (at least in the ideal case), but current is specific to each isolated power block (as water flow is specific to the bathtub, the toilet, the dishwasher, etc.). The booster current is the sum of the current in each of the isolated blocks.

So, to answer your question, you need a RRampmeter in series with any location where you want to know the current. If you place it at the booster, it will read the total layout current. If you place it in series with a block feeder, it will measure the current in that block only. So each power district requires its own RRampmeter if you want to know the current flow in that block.

You can connect the RRampmeter either before or after a circuit breaker. If you want to know the track voltage the train sees, it should be after the circuit breaker. Note, however, that the RRampmeter is powered by the track voltage, so if it is after the circuit breaker and the circuit breaker turns off, the RRampmeter will turn off. If you place the RRampmeter before the circuit breaker, it will remain on even if the circuit breaker turns off, but it will read a voltage somewhat higher than the actual track voltage. Note with a PSXX circuit breaker, the voltage difference will not be significant.

As mentioned above, the RRampmeter is powered by the track voltage, and needs about 7 volts to operate. With DCC, there is always voltage on the track, so a battery is not required unless you want it to work in situations where the input voltage might be less than 7 volts. The RRampmeter will also work on a DC layout or AC layout where the track voltage varies to control train speed. In this case, the voltage may be below 7 volts when you are operating your layout, so you might want to consider the battery version.