Contrec 202A User manual

202A-M-V3.1
FIELD MOUNTED
RATE TOTALISER
MODEL 202A
June 2017

202A-M-V3.1

202A-M-V3.1
CONTENTS
1. Introduction 3
1.1 Model Number Versions 4
1.2 Intrinsic Safety Approvals 6
1.3 Operation 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 Maintenance 30
7.7 Terminal Designations 31
Index 32

202A-M-V3.1

202A-M-V3.1
Introduction 3
1. INTRODUCTION
The Model 202Ai 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.
The Model 202Ai Rate Totaliser conforms to the EMC-Directive of the Council
of European Communities 2004/30/EU, the LVD directive 2014/35/EU and the
following standards:
EN61326:2013 Electrical equipment for measurement, control
and laboratory use – EMC requirements :
Residential, Commercial & Light Industry
Environment & Industrial Environment.
EN61010:2010 Safety requirements for electrical equipment
for measurement, control, and laboratory use.
In order to comply with these standards, the wiring instructions in Section 7.5
must be followed.

202A-M-V3.1
4 Introduction
1.1 MODEL NUMBER VERSIONS
The Model Number describes the options available for the 202Ai as follows:
Model 202Ai . x
where x denotes the mounting options and will be replaced by one of the
following numbers:
0No holes drilled for cable entry
1Panel mount
2Wall mount (standard)
6for Pipe mounting
The Wall mount instrument is supplied with cable glands that are watertight
and have integral strain relief.
Approval Versions
C CSA USA / Canada Approval
M ATEX/IECEx Approval

202A-M-V3.1
Introduction 5
The Model 202A

202A-M-V3.1
6 Introduction
1.2 INTRINSIC SAFETY APPROVALS
The Model 202Ai is certified for use in hazardous areas and has IECEx, ATEX
and CSA U S/C approvals.
The Model 202Ai certification details are:
IECEx Approval IECEx BVS 15.0099X
Rating Ex ia llB T4 Gb
ATEX Approval BVS 15 ATEX E 106 X
Rating II 2G Ex ia IIB T4 Gb
Ambient Temperature: Maximum ambient temperature of 60°C.
CSA US/C Approval LR 104 840-5.
Type: Class 1, Groups C and D.
When installing in hazardous areas, the instrument must be installed
according to the guidelines in Section 2 and in accordance with the local
relevant 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

202A-M-V3.1
7 Specification
1.3 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.

202A-M-V3.1
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.

202A-M-V3.1
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.

202A-M-V3.1
10 Programming
3. PROGRAMMING
The Model 202A is fully programmable, with all parameters being stored in non-
volatile memory.
The Program Mode can be entered in the following way:
By removing the lower cover strip (i.e. the dark grey strip along the
bottom of the enclosure) and replacing it the wrong side up. This brings a
small magnet on the inside of the cover strip in contact with a reed switch
inside the instrument.
The PROGRAM switch is used to step through the program (CAL sequences) and
The and keys on the front panel are used to change and increment the
flashing digits.
The CAL number is displayed on the lower display and the parameter is displayed
on the upper display.
Parameters in Program Mode that consist of the two parts, whole numbers
and digits after the decimal point, are restricted to having a maximum of 6
significant digits. Therefore the number of significant digits entered in the
whole numbers determines the number of digits that are able to be entered in
the digits after the decimal point.
For Example
000001 in the whole numbers makes 00000 available after the decimal place.
000100 in the whole numbers makes 000 available after the decimal place.
010000 in the whole numbers makes 0 available after the decimal place.

202A-M-V3.1
Programming 11
3.1 PROGRAM STEPS
Step Comment
CAL 00 Pulse Output.
0 = No pulse output, low and high alarms
1 = Scaled pulse output and low alarm
CAL 01 Span - whole numbers.
CAL 02 Span - digits after the decimal point.
The Span is the number of units of measure per
timebase (e.g. litres/sec, Gal/min). The Span can be
programmed in the range of 0.000001 - 999,999.
See section 3.2.
CAL 03 Cutoff Point.
This determines the cutoff point as a fraction of Span.
See section 3.2.2.
CAL 04 Decimal Point for Rate Display.
The flowrate can be displayed with 0, 1, 2 or 3
decimal point places.
CAL 05 Timebase for Rate.
The Rate can be displayed in units per second,
minute, hour or day.
0 = second
1 = minute
2 = hour
3 = day.
See section 3.2.

202A-M-V3.1
12 Programming
Step Comment
CAL 06 Filter.
Fluctuations in the flowrate can be filtered out so
that the Rate is held steady. The filter value is
programmed between 1 - 99 where "1" represents
no filtering and 99 is maximum.
See section 3.4.
CAL 07 Decimal Point for Total Display.
The totals can be displayed with 0, 1, 2 or 3
decimal points.
CAL 08 Total Conversion Factor - whole numbers.
CAL 09 Total Conversion Factor - digits after the decimal point.
The Total Conversion Factor enables the Rate to
be displayed in one engineering unit and the
Totals to be displayed in another engineering unit.
The Total Conversion Factor can be programmed
in the range of 0.000001 - 999,999. Set to 1.000
if totals and rate are in the same unit eg. litres.
See section 3.3.
CAL 10 Low Alarm - whole numbers.

202A-M-V3.1
Programming 13
Step Comment
CAL 11 Low Alarm - digits after the decimal point.
CAL 10 & 11 program the flowrate below which the
low alarm relay will close. The value can be
programmed in the range 0 to 999,999.
CAL 12 High Alarm or Pulse Output Factor - whole numbers.
CAL 13 High Alarm or Pulse Output Factor - digits after the
decimal point.
CAL 12 & 13 program the flowrate above which
the high alarm relay will close. The value can be
programmed in the range 0 to 999,999.
If the pulse output is selected (see CAL 00), the value
will represent the total per pulse. eg. 5 litres per
pulse.
CAL 14 Input Flow Relationship.
0 = Linear Input
1 = Square Root Input
CAL 15 Accumulated Total Reset.
CAL 15 displays the accumulated total which can
be reset by pressing and holding the RESET key for
about 5 seconds.
SOFT Software Version.

202A-M-V3.1
14 Programming
3.2 CALCULATION OF RATE AND TOTAL
3.2.1 Analog Input
The flowrate, R, is calculated as follows:
R = SA if the linear relationship is selected
or R =Sif a square law relationship is selected
where A = the input value
S = the span
At the minimum input (i.e. 4mA), A = 0, and at the maximum input (ie.
20mA), A = 1.
The Span, S, can be set during calibration anywhere in the range of 0.000001
to 999,999.
The Span, S, is programmed in units of volume per timebase (ie. litres/minute
or kilograms/hour). This also means that the Total will be displayed with the
same unit of volume, ie. litres or kilograms.
A

202A-M-V3.1
Programming 15
3.2.2 The Cutoff Point
Because many transducers do not always exactly transmit 4mA when they
are at zero rate, it is often necessary to define a rate below which no
integration takes place. This is termed the cutoff point and is programmed
as a percent age of the Span, S.
For example, if S = 2200 kg/min in a square law system, and the cutoff point is
set at 20.0%, the actual cutoff rate Rc can be determined as follows:
The cutoff rate is defined as:
At 20% cutoff,
Rc = 2200 x 0.2
= 440 kg/min
The value of A which would produce this cutoff is:
A = 0.04
and the input signal would be:
I = 16mA x 0.04 + 4mA
= 4.64mA
A2200Rc =
0.2)(since 0.04 =

202A-M-V3.1
16 Programming
3.3 TOTAL CONVERSION
The Total Conversion feature enables the rate to be displayed in one
engineering unit (e.g. gallons/minute) and the totals to be displayed in
another engineering unit (e.g. barrels).
The Span is always programmed in the unit relating to Rate, and the
Total Conversion constant is a division factor which can be used to
convert the totals to the different unit. The Total Conversion factor
affects the resettable and accumulated totals.
For Example.
If the Rate is required in gallons per minute:
1. The Span would be programmed as gallons per minute.
2. The timebase would be programmed as minutes.
If the Totals are required in barrels:
3. The Total Conversion factor is programmed as 42 (there are 42
gallons in a barrel). All totals will now totalise in barrels.
Some common units are given below together with the Total Conversion
constant which should be programmed.
Rate* Totals TOTCON
Gallons (US)/ Barrels (oil) 42.000
Litres/ Kilolitres 1000
ml/ Litres 1000
Mgallons/ Acre-feet 0.32587
* Units per second, minute, hour or day. The timebase is programmed
separately during Programming.

202A-M-V3.1
Programming 17
3.4 FILTERING
Frequency fluctuations caused by pulsating flow through a flowmeter, often
makes the Rate impossible to read with any precision.
The Model 202A has a digital filter which will average out these fluctuations
and enable the Rate to be read to four digit accuracy. The ability to select a
suitable filtering level means that highly accurate and stable readings can be
obtained without excessive lag.
The diagram below shows a pulsating signal input together with the effect
of filtering.
As a guideline to the degree of filtering to be used, the following table shows
the response to a step change in input. The value, CAL 06, is the filter
constant which is programmed during the Programming routine. The times
for the display value to reach 90% and 99% of full swing are given in seconds,
for different values of CAL 06.

202A-M-V3.1
18 Programming
A 90% 99%
1 0 0
2 1 2
4 2 4
6 3 6
10 5 11
15 8 17
20 11 22
25 14 28
35 20 40
45 25 51
60 34 69
75 43 86
90 52 103
99 57 113
Table 1 - Response to a step Input (in
seconds).
Note that if CAL 06 is set to 01 there is no filtering of the input signal.