Yokogawa 202 User Manual

FIELD MOUNTED

RATE TOTALISER

MODEL 202A

2 August 1999

CONTENTS

1. Introduction 3

1.1 Model Number Designation 4

1.2 Operation 6

1.3 Intrinsic Safety Considerations 7

2. Specification 8

3. Programming 10

3.1 Program Steps 11

3.2 Calculation of Rate and Total 14

3.3 Total Conversion 16

3.4 Filtering 17

3.5 Example 19

4. Signal Input 20

5. Alarm & Pulse Outputs 21

6. Intrinsic Safety Connections 23

7. Installation 25

7.1 Wall Mounting 25

7.2 Panel Mount Version 26

7.3 Removing the Front Panel 27

7.4 The Main Electronics 29

7.5 Wiring 30

7.6 Terminal Designations 31

Index 32

Introduction 3

1. INTRODUCTION

The Model 202A Rate-Totaliser is a microprocessor based instrument designed to
measure a 4-20mA signal from flowmeters and pressure transducers. The
instrument can be programmed to display directly in engineering units and
includes features such as linear or square law calculation, integration and digital
filtering.

Rate, Total and Accumulated Total can be displayed in engineering units on the
large LCD display. A front panel switch selects the function for display and a
Reset button allows the Total to be reset to zero.

The instrument is fully programmable, with all calculation constants set via the
front panel switches and stored in a non-volatile memory which will retain data
indefinitely. The user can program span, filtering levels, display resolution and
cutoff point.

The instrument is powered from a 4-20mA input signal and therefore, requires
no external power.

This instrument conforms to the EMC-Directive of the Council of European
Communities 89/336/EEC and the following standards:

Generic Emission Standard EN 50081-1 Residential, Commercial & Light

Industry Environment.

Generic Emission Standard EN 50081-2 Industrial Environment.
Generic Immunity Standard EN 50082-1 Residential, Commercial & Light

Industry Environment.

Generic Immunity Standard EN 50082-2 Industrial Environment.

In order to comply with these standards, the wiring instructions in Section 7.5
must be followed.

4 Introduction

1.1 MODEL NUMBER DESIGNATION

The Model Number of an instrument describes which input and output options
are installed.

Model 202 A. 1 0

Input Options

A for 4-20mA no options available at this

time

Mounting

1 for panel mounting
2 for field mounting
6 for pipe mounting

Introduction 5

The Model 202A

6 Introduction

1.2 OPERATION

The Model 202A Rate Totaliser will display:

Rate
Resettable Total
Accumulated Total.

Both the Rate and Resettable Total are continuously displayed while the
Accumulated Total is only displayed when the ACCUM TOTAL key is pressed.
The Resettable Total can be reset at any time by pressing the RESET key.

The instrument also has a test mode which can be entered by simultaneously
pressing all three front panel keys. The tests are as follows:

Lo Test By pressing the ACCUM TOTAL key, the low alarm output

will go low.

Hi Test By pressing the RESET key, the high alarm output:

a. will go low if CAL00 = 0 (high alarm output),
b. will output 100ms pulses every 0.5sec if CAL00 = 1 (scaled
pulse output).

Display Test By pressing the PROGRAM key, all segments of the display

will show.

To exit the test mode, simultaneously press all three front panel keys.

Note that when the input signal drops below 3.75mA (4-20mA input), a signal
error will occur. The display will alternate between the current total and the

word "SIGNAL". When the input signal drops below ≈3.5mA the Model 202A
shuts down saving totals in the non-volatile memory.

Introduction 7

1.3 INTRINSIC SAFETY CONSIDERATIONS

The Model 202A is certified for use in hazardous areas and has both CENELEC
and CSA NRTL/C approvals.

The Model 202A certification details are:

CENELEC Approval: Kema 98.E.1873.
Type of Protection: Ex ia.
Group: IIB.
Temperature Class: T4 at ambient temperature of 60°C.

CSA NRTL/C Approval
File Number: LR 104 840-5.
Type: Class 1, Groups C and D.

When installing in hazardous areas, the instrument will have to be installed
according to the guidelines given in section 6 and in accordance with standards
for wiring and installation in hazardous areas.

4-20mA Input

The input can be connected to IS circuits with the following maximum
values:

Ui = 28V
Ii = 93mA
Pi = 653mW.

Relay Outputs

The outputs can be connected to IS circuits with the following maximum
values:

Ui = 28V
Ii = 93mA
Pi = 653mW.

8 Specification

2. SPECIFICATION

General

Display: LCD, which is continuously powered.
Resettable Total: 7 digits with 10mm (0.4") high digits.

Resettable from front panel.

Accumulated Total: Displayed when the Accumulated Total button is

pressed.
Rate/Display: 5 digits with 8.5mm (0.33") high digits.
Span: The units of measure per timebase (eg. gallons/sec) is

programmable in the range 0.000001 to 999,999.
Decimal Points: Decimal Point positions are fully programmable for

both rate and total.
Timebase: Span can be programmed in units per second, minute,

hour or day.
Signal Type: 4-20mA.

4-20mA Input

Resolution and
Linearity: 0.05% of span.
Accuracy: 0.05% of span @ 25°C.

0.1% (typ) of span, full temperature range.
Update Time: 0.5 seconds.
Connection: Two wire.
Voltage Drop: 2.5 volts maximum.

Specification 9

Outputs

Type: Two open collector outputs suitable for driving DC

solenoids or external relays. The outputs provide high
and low flow alarms or pulse output and low flow

alarm.
Switching Power: 200mA. 30VDC maximum.
Saturation Voltage: 0.8VDC typical across the output in the "on" state.
Isolation: Both outputs are separately opto-isolated.

Pulse Duration: If CAL00 = 1 (scaled pulse output):
(for pulse output) a. 1ms if output frequency > 50Hz,

b. 10ms if output frequency is 5 ... 50Hz,

c. 100ms if output frequency is < 5Hz.

Physical

Temperature: Operating Temperature: -20°C to 60°C.
Dimensions: 97mm (3.8") high x 150mm (5.9") wide x 41mm

(1.6") deep (cable glands not included).
Protection: Sealed to Nema 4x or IP67 standards.
Cable Entry: By cable glands.
Wall Mounting: Universal Mounting Bracket supplied as standard.
Pipe Mounting: A galvanised metal bracket is available which enables

the Model 202A to be attached to a 2" vertical or

horizontal pipe.
Panel Mounting: Supplied with mounting brackets.

Terminals accessible from rear (Note that the panel

mount version is not watertight).

Cutout: 141mm (5.6") wide x 87mm (3.4") high.