Toshiba LF470- Manual

EJL-142A

Field Intelligent Device Series

Electromagnetic Flowmeter

LF470/LF622

2.5,4,6mm (1/10",1/6”,1/4")

Introduction

The electromagnetic flowmeter uses Faraday’s Law of
electromagnetic induction to measure the process flow.
The device consists of two units: a detector, through
which

the

fluid

to

be

measured

flows

and

in

which

low-level signals proportional to flow rates are
obtained; and a converter, which supplies excitation
current to the

detector,

and

amplifies

the

signals

from

the

detector and

then

processes

and

converts

the

signals

into

the

4–20

mA

dc current

signal. The LF470

is a small meter size detector designed to measure a
small amount of fluids containing substances such as
chemicals.
The wetted materials for the LF470 are corrosion
resistant ceramic and platinum electrodes and are
applicable to almost any kind of fluids. The LF470 is a
lightweight palm-sized detector.
Combining with a LF622

multifunctional

converter

which

has

an

improved

noise-suppression circuit and

advanced algorithms. The LF470 is highly resistant to
noise and provides a stable output even for fluids
containing slurries. IR (Infrared) switches enable
parameter setting of the converter without removing
the cover. Flow direction can be set in either way, and
its unique 128 x 128 dot matrix LCD display allows
the LCD to be rotated electronically to 90, 180 and 270
degrees without opening the cover
The AF900 hand-held terminal (HART*

1

communicator) can be used to communicate with the
flowmeter from a remote place. PROFIBUS-PA*

2

or

Modbus*

3

interface is available as an option.

*1 : HART protocol (Highway Addressable Remote Transducer) is a

commu nication protocol for indu strial sensors recommended by the

HCF (HART Commu nication Foundation).

*2 : PROFIBUS is the commu nication protocol for factory and process

automation that the PROFIBUS Organization recommends. Instead of

analog control with a conventional analog signal (4 -20mA), it is

fieldbus which digitizes all signals. Flowmeters su pport

PROFIBUS-PA.

*3 : Modbus is the commu nication protocol that Modicon Inc. developed.

Physical layer is RS485.

Figure 2. Electromagnetic Flowmeter

LF470/LF622

Specifications

Overall Specifications

Measurement range in terms of flow velocity:

0–0.3 m/s to 0–10 m/s. (0–1.0ft/s to 0–32.8ft/s).

Accuracy:

The overall accuracy combined with the

LF622 converter is shown in the following table.

Accuracy

Flow rate as a
percent of range

0.3-1.0m/s

(1.0-3.3ft/s)

1.0-10m/s

(3.3-32.8ft/s)

50

〜

100

％

±

0.8% of FS

±

0.8% of rate

0

〜

50

％

±

0.8% of FS

±

0.4% of FS

Note:

The accuracy is measured under standard

operating conditions at Toshiba's calibration facility.

Fluid conductivity:

50µS/cm minimum

Fluid temperature:

Pipe connection material Fluid temperature

Stainless steel and other metals

−

10

℃〜＋

120

℃

(

14 to 248 

°

F

)

Polyvinyl chloride
(shock -resistant)

−

10

℃〜＋

60

℃

(14 to 140 

°

F)

Ambient temperature:

–10 to +60

°C

(14

to

140

°F)

Structure:

IP67

Power consumption:

・

When combined with the LF622 converter:

Standard:10W(14VA)

at AC100V and Excitation current:0.2A

MAX:15W (22VA)

Fluid to be
measured

Signal cable

Excitation cable

Power supply

4-20mA dc output
and pulse output

LF622 Converter

LF470
Detector

Figure 1. Configuration Diagram

LF470

LF622

Certification number

Z01207