Wireless Mini Loggers LR8512, LR8513, LR8514, and LR8515

HIOKI Technical Notes Vol. 2 2016 No. 1

Data can be downloaded both during and after

measurement. Since data is not segmented even when

downloaded during measurement, data from ongoing

measurement can be checked whenever the user desires.

B. Power-Saving Function for Long Battery Life

Devices equipped with wireless functionality tend to use

batteries quickly due to high power consumption, not only

while communicating, but also in standby mode.

To avoid this potential pitfall, Hioki equipped these

products with functionality for activating Bluetooth wireless

technology only during preset times as dened by a power-

saving schedule. Shorter wireless utilization times translate

into longer battery life, and battery-powered operating time

can approach about 3.5 months when wireless functionality

is turned off (LR8514 with a recording interval of 1 min.;

reference value at 23°C [73.4°F]).

The schedule can be set in terms of dates, days of the

week, and times.

C. Ability to Download Data to a Tablet or Computer

No dedicated device is needed in order to download data

from the products, which can send data to an Android tablet,

Android smartphone, or Windows computer.

When the Bluetooth wireless function is turned on, the

ease with which a third party can establish a communications

Abstract—The Wireless Mini Loggers LR8512, LR8513,

LR8514, and LR8515 can send data from a remote location to tablet

or computer wirelessly, without complex conguration. This paper

describes the features, architecture, and other characteristics of

these products.

I. IntroductIon

The LR8512, LR8513, LR8514, and LR8515 enable

measurement data to be checked wirelessly from a remote

location. Consequently, they enable voltage and current

to be measured safely even when positioned inside a

distribution panel or control panel since the panel’s cover

can be left closed as no wires need to be routed outside the

panel. Similarly, they make it possible to check data such as

temperature and humidity inside a clean room from outside

the room. In this way, these products allow data from high

locations or locations from which it would be difcult to

establish a wired connection, for example from a moving

piece of equipment, to be checked from a safe location.

Furthermore, the LR8512, LR8513, LR8514, and LR8515

can be used as measurement units for the Wireless Logging

Station LR8410, making it possible to use them to implement

real-time measurement with the LR8410 or to place them

in the eld to collect data on their own, as merited by the

characteristics of the particular application at hand.

II. overvIew

The LR8512, LR8513, LR8514, and LR8515 are compact,

two-channel loggers that incorporate Bluetooth wireless

technology. This product line consists of four models

for pulse (LR8512), load and leakage current (LR8513),

temperature and humidity (LR8514), and voltage and

thermocouple (LR8515) measurement.

At the same time, Hioki has developed software for

downloading data to Android handsets and Windows

computers.

III. Features and FunctIons

A. Ability to Collect Data From Remote Locations

Wirelessly

The products incorporate Bluetooth wireless technology,

enabling data recorded by the logger to be downloaded to a

tablet or computer in a remote location.

Wireless Mini Loggers

LR8512, LR8513, LR8514, and LR8515

Takayuki Kurashima

Engineering Division 1, Engineering Department

Appearance of the LR8514.

Wireless Mini Loggers LR8512, LR8513, LR8514, and LR8515

HIOKI Technical Notes Vol. 2 2016 No. 1

connection is undesirable from a security point of view. The

products address this issue with a password authentication

function. Control is only accepted via communications

with terminals whose legitimacy has been authenticated

with a password. All device control instructions via

communications from terminals that have not been so

authenticated are ignored.

D. Four Models From Which to Choose, Depending on the

Application

Fol low i n g a r e descript ions of each of the fou r appl icat ion-

specic models:

1) Wireless Pulse Logger LR8512: The LR8512 can

record pulse integrated values, frequency of rotation,

and logic ON/OFF signals. For example, it can be used to

measure signals such as pulse output from a ow meter and

record daily uctuations.

2) Wireless Clamp Logger LR8513: With the addition of

an optional clamp current sensor, the LR8513 can perform

AC/DC load current, AC leakage current, and simple power

measurement. If the voltage value and power factor value

are set in advance, it can perform simple power calculations,

generating results for a 1-phase/2-wire circuit that can be

read directly on the instrument.

This model also offers an average value recording mode

that records the average of values measured at a sampling

speed of up to 0.5 seconds, making it easy to ascertain

demand at a 30-minute interval.

3) Wireless Humidity Logger LR8514: With the addition

of an optional temperature and humidity sensor, the LR8514

can measure temperature and humidity, providing a simple

solution for recording and managing those environmental

characteristics.

The ability to connect two sensors with different cable

lengths to the instrument is useful in applications where it

is necessary to compare temperature and humidity readings

inside and outside a given piece of equipment, for example.

4) Wireless Voltage/Temp Logger LR8515: The

LR8515 can measure DC voltage and temperature using

a thermocouple (K or T). Users can select from several

voltage ranges (±50 mV f.s., ±500 mV f.s., ±5 V f.s., and ±50

V f.s.), enabling this single instrument to measure voltages

ranging from minuscule signals from actinometers or heat

ow sensors to battery voltages.

Since voltage and thermocouple settings can be set for

each channel, it is possible to view the correlation between

voltage and temperature using a single instrument.

Iv. archItecture

A. Hardware Architecture

Fig. 1 provides a block diagram for the LR8512 as

a representative model of the series. A 16-bit one-chip

Measurement section

Bluetooth

controller

module

LCD

CPU

Switch

× 3

Flash ROM

(32 Mibit

†

)

FRAM

(16 Kibit

†

)

Low-pass

filter

Low-pass

filter

Attenuator

Comparator

Attenuator

Counter

CH1+

CH1-

Input

Power

circuit

3.3 V

AC adapter

External power

LR alkaline batteries

(AA size) × 2

Switch

Measurement

3.3 V

Power

circuit

Measurement

5 V

3.3 V

Switch

CH2+

CH2-

Comparator

Lithium battery

(Clock backup)

Crystal

oscillator

Fig. 1. LR8512 measurement circuitry and overall block diagram.