DVM2130 Digital Voltmeter Overview: Virtual Brew 10/17/2024

In this episode of Virtual Brew, our free monthly webinar, Field Data Solutions Specialist Lon Duke walks you through the DVM2130, our purpose-built, rugged digital voltmeter, and how it seamlessly integrates with the PCS Field Data Collector (FDC) app.

In this session, you will learn how to utilize the DVM module in FDC to:

• Observe your readings
• Configure your interruption settings
• Capture waveforms and attach to a survey
• Send data wirelessly to PCS Survey Manager

Resources from this episode: Download the PDF guide for a walkthrough of the content covered in this episode.

Transcripts

Introduction

Lon
Today we’re going to look at the DVM 2130 — we’ll mainly focus on that, which is our standalone DVM that connects via Bluetooth to tablets — and then we’ll look at the FDC DVM module inside the FDC app.

DVM 2130 Background

So, the 2130 — a little background on this: it was designed in-house. The first one we had was the DVM 1100, which was for the QX. Then we have the DVM 1110, and the DVM 2130, which is for FDC and other FDC products. It was built with CP in mind — very high accuracy — that was the whole design intent, built around the CP industry.

This one does have a built-in GPS, for both location and timing — so if you’re doing interruption, the location is about 2 to 5 meters of accuracy on the GPS, it’s consumer grade, pretty much matches what your phone is.

There’s really good filtering on this, designed into the circuitry, so any type of AC noise or other signals are going to be filtered out. It is sealed, so it’s made for being out in the field, harsh conditions — and it connects via Bluetooth, so you don’t have to have it right there with your tablet. If you need to set it up where you’re taking your measurements and go sit in your truck, you can, within about 30 feet, whatever the Bluetooth range is — and that’s for the 2130 only, with the USB-C cable.

Battery

If you’re out in the field, this should get you a good full day of measurement. If it’s starting to get low and you’re still doing your surveys, you can hook it up to your Mesa tablet, via the USB-A on the Mesa, and the Mesa tablet will charge the DVM out in the field.

Inputs

The inputs on this — it’s a standalone unit, and it has several inputs. The first one is the remote trigger — if you’re using our survey probes or the data cane, the button on there is where this will trigger the reads. We have a voltage input, we have the common, and then we have a shunt input.

So, like I said — if you’re doing a pipe-to-soil, which is AC or DC, you’ll be using that red 250-volt input, and the common, for your reference cell. When you’re measuring a rectifier — the rectifier output volts — you’ll use that red input and the common, that black input, to get your voltage. You’ll use the shunt input, the blue one, to get the measurement across your shunt — we’re measuring millivolts across the shunt and converting that to amps.

DC and AC Specs

Some of the specs on this, for DC and AC — the range: we have the 500-millivolt range, which is going to be any type of current field — any type of bond, anything you’re measuring with a shunt, you’re going to use that blue 500-millivolt input. We have a 5-volt range and a 250-volt range — those all have an accuracy of 0.1%.

For AC — for any type of AC current, that’s a 350-millivolt range, and then we have the 3.5 and the 175. The reason those aren’t 250 is that for AC, you’re actually measuring AC RMS. If you have any questions on that, let us know — but for RMS, you’re not getting your peak-to-peak, so 250 peak-to-peak is going to be about 175 volts for RMS.

Input Impedance

The input impedance on this — for CP, the standard is that you have at least 10 megaohms or greater for any type of CP measurement. This one is at 100 megaohms input impedance — again, this was designed for CP.

So, if you’re looking at what you’re reading from your meter versus the actual true potential — if you run it through the formulas, just for comparison: VM is your meter, your true voltage is E, T; RM is your meter input impedance, and RT is the rest of the external resistance of that circuit. So, if you have a DVM that’s 1 megaohm input impedance, you can get a little over 9% error. If you’re using 10 megaohms, which is the minimum you need for CP, you’re going to get about 1% error — and that’s good. What we have is 100 megaohms input impedance — if you’re doing that same circuitry, that’s where we’re getting that 0.1% accuracy.

Calibration

We do calibration in-house — and when we say we do calibration, we actually do a calibration, this is not just a verification, and we’ll send it back to you. This is run through a program that measures multiple ranges, and if any range is anywhere out of our spec, we will adjust it and get it back into range. So it’s a true calibration, and you get a certificate of that calibration, with all of the ranges that have been run through.

If you want to see what your calibration status is, go into Settings, and About — you’ll see a calibration date. Those are valid for one year — we guarantee those for one year.

Q&A

[Moderator]
Real quick, some questions — one from Sergio: do you need AC filtering when doing CI surveys with the DVM?

Lon
You can pick up noise, any type of stray current, from anywhere — it could be AC — yes, it’ll filter out that AC for CI surveys.

[Moderator]
And then Paul had asked: what is the filtering that’s actually happening in the DVM, to remove those undesirable signals — what type of filtering is going on?

Lon
That’ll have to get with the developers of this, the engineering team, and we can get you the details on that — if you can hang on, we’ll send you any type of details you need on that question.

Connecting to the Mesa Tablet

So, if we’re going to connect the DVM to — in this instance, our Mesa tablet — you have two options. The first option is just to open up the DVM module — it’s pretty simple, it’s an easy way to go, it’s the way I do it, because if you open up the DVM module without it being connected, it’s going to bring up the connection screen. The other option is to go through Settings, Connections, and DVM, and you’ll go to the same screen. Now, if you ever need to disconnect, you’ll need to go to Settings, Connections, and DVM.

LEDs and GPS

Some of the LEDs on the front, just to let you know: when you turn the DVM on, at first it’s going to be solid, then it’s going to flash rapidly when it’s looking for something to pair, and once it’s paired up with the field data collector, it’ll start blinking about once a second. For charging, it’s going to blink when it’s charging, and be solid when it’s fully charged. The USB-C is for charging — again, you can connect that to your Mesa tablet as well. The power button — you’ll just hold it down; if it’s turned on, hold down the power button till it starts flashing, and then let it go.

And again, this has GPS built into it — so if you’re looking at your GPS module within FDC, you’ll see the source is coming from the DVM. It’ll give you the last five digits of the serial number, and let you know the DVM is connected — that means all of your positioning data is coming from the DVM.

The DVM Module

So, let’s look at the DVM module itself. When you open up the DVM module, we have several options — we can measure volts DC, volts AC, DC amps — now, DC amps requires a shunt, we again measure millivolt values across a shunt and calculate what your current is, and that’s where you’re using that 500-millivolt input. We also do AC current, AC amps, and again, that requires a shunt — you’ll need a shunt and use that blue 500-millivolt input.

DVM Settings

So, some of the settings inside the DVM: if you’re in the DVM, you have the gear icon up at the top, and that’s for different types of settings — mainly for setting your method, your survey method, and setting your waveform options. There’s also thresholds, so you can set threshold lines that show across your graph — say, an 850 threshold line, if I want.

So, if we go into these right now — you see we’re looking at a single reading, so we’re in Single Read mode. If we go in here and look at the method, and the method is Single Read, we can switch that over to GPS Sync. So, if we’re going to do any type of interrupted survey, this is where we’re going to set our interruption settings — this needs to match whatever our interruptor is doing.

So, now, once I have that turned on, I’m getting an on/off pair — so I got a 1108 and a 988, I got an on/off pair now, so I’m looking at an interrupted survey.

Reading the Waveform

So, if I want to look at the waveform, I go to the Waveform icon. Now, let me say this — if you’re doing any type of interrupted survey, I can’t stress this enough: before you set up anything, hook up to your pipe, look at your pipe-to-soils, and open up the DVM and look at the waveform — because this is where you’re going to make sure you’re synced up, and you’re getting a true on and a true off potential.

So, we have the first setting, our on setup — in this case, we’re 150 milliseconds before the on-to-off transition; anytime you see “setup,” it’s going to be before. We also have an off delay, which is 150 milliseconds in this case, after the on-to-off transition, to get our true instant-off, or polarized, potential.

This off delay is the one thing you’ll probably move the most — the on setup is usually pretty flat, so you don’t really need to adjust that much, but this off delay, you need to look at that and get it dialed in, to where you’re getting a true off reading.

The other setting here that’s really important is “cycle begins with” — this just needs to match your interruptor. If your interruptor is set to cycle begins with on, just match it up. You’ll see right away if this is offset — if this waveform is offset by a second, it’s probably your “cycle begins with” setting. Most companies will just go with a single setting, either on or off, so you’ll match that up.

Saving a Wave Print

Save a wave print from the waveform — you select the camera icon up at the top, and you’ll give this a name — usually you’re going to give this a location, in this case I’ve got Milepost 216 at Rawlings Road, so you know where this was recorded. Once you save this off, one of the options you have is you can send this over the air to Survey Manager, and import it into Survey Manager — you can bring up your survey, so you have a CI survey, and you’re looking at the chart, and you know this is where this waveform was taken, because I’ve posted it there — I can attach it to that CIS chart, and it’ll give me a little icon at the bottom letting me know there’s a waveform tied to this.

Q&A

[Moderator]
Hey, Lon, we actually had a question a second ago from Mike Hogart. He asked — after setting up a DVM with method equals GPS Sync, we’ve had multiple users report the unit returning to Single Read — is there a way to keep it on GPS Sync for the entire survey? And he also followed up with: is “waveform tied to inspections” CIS only, or CPDM as well?

Lon
Currently, for Survey Manager, you’ll do that in CI, in the indirect survey. As far as reverting back to Single Read — it kind of depends on what you’re talking about. If you’re in here and doing a periodic survey, you can apply these settings to the periodic survey — but if you’re opening up a CI survey and starting that brand new, you want to make sure the settings in the properties of that CI survey match what you’ve done here.

But essentially, Mike — once you set up the DVM screen to have the settings you like, the button in the upper right-hand corner says “Apply To” — you can apply that to your periodic survey, and it’ll permanently apply those settings. You can change them, obviously, internally, inside each of those surveys individually, if you need to make changes on the fly — but this allows you to send your specific volt-meter settings — method, cycle time, whatever you need — to your periodic surveys. So it’s just in that upper right-hand corner.

[David]
We’ll follow up with anything else you need, or any specific use cases. Please let us know any other questions — we do have a couple of minutes left, so if you’d like to either type your question in the chat, or just unmute yourself and go ahead and ask it, feel free to do so — we’ll give another minute or so, if anybody has any other questions.

Closing

[David]
Okay, well, it looks like we’ve reached the end of Virtual Brew for October. We really hope to see everyone in the next couple of weeks at Users Group — we’re really slated to have a great event, and we’re excited to have everyone in Austin. Please — we will do a follow-up presentation, and obviously any type of information we have here — Mike and Paul will take offline and get you answers, maybe more expanded ones you need.

And also, we had one more question here, from Kurt —

Lon
You’re absolutely right, Kurt — you can apply it to either of your survey types, if you start in that DVM app — it does give you a drop-down to apply those settings, CI or periodic, depending on how you want things. And you can also be inside the surveys independently, and set up your DVM functionality there as well — so it’s not always tied to global settings.

[David]
But, like I said, we’ll follow up with any type of questions, send links to the tech specs of the DVM, as well as links to the user guide on setting up FDC and the DVM methods that Lon went through. We really hope you have a great rest of the week, and a great lead-up to November. Exactly — so keep an eye on your email for the follow-up, that’s usually on Mondays following the Virtual Brew, where you’ll be able to rewatch the presentation today — we’ll send links to resources there as well. And mark your calendars for the last Virtual Brew of the year — it’s actually going to be on December 5th, Thursday, December 5th — so it won’t be on our usual third Thursday of the month, due to the holiday season. So, stay tuned for some more details on that one. Have a great day. Thank you — thanks, everybody.