Contrec 104A User manual

104A-M-V1
FIELD MOUNTED
RATE TOTALISER
MODEL 104A
11 October 2013

CONTENTS
1. Introduction 3
1.1 Model Number Versions 4
1.2 Intrinsic Safety Approvals 4
1.3 Operation 6
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. Installation 25
6.1 Wall Mounting 25
6.2 Removing the Front Panel 26
6.3 The Main Electronics 28
6.4 Wiring 39
6.5 Maintenance 39
6.6 Terminal Designations 30
Index 31

Introduction 3
1. INTRODUCTION
The Model 104A 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 104A Rate Totaliser 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 VERSIONS
The Model Number describes the options available for the 104A as follows:
Model 104A . x
where x denotes the mounting options and will be replaced by one of the
following numbers:
0No holes drilled for cable entry
2Wall mount (standard)
6for Pipe mounting
The Wall mount instrument is supplied with cable glands that are watertight
and have integral strain relief.
1.2 INTRINSIC SAFETY APPROVALS
The Model 104A is not certified for use in hazardous areas.

Introduction 5
The Model 104A

7 Introduction
1.3 OPERATION
The Model 104A 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 104A
shuts down saving totals in the non-volatile memory.

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 104A to be attached to a 2"
vertical or horizontal pipe.

10 Programming
3. PROGRAMMING
The Model 104A 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 (ie. 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.

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
(eg. 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.

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.

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.

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 (ie. 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

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
percentage 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 =

16 Programming
3.3 TOTAL CONVERSION
The Total Conversion feature enables the rate to be displayed in one engineering
unit (eg. gallons/minute) and the totals to be displayed in another engineering
unit (eg. 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.

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 104A 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.

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.

Programming 19
3.5 EXAMPLE
A vortex flowmeter has a maximum output of 20.538 litres/min at 20mA. It is
required to display the flowrate in litres/min with 1 decimal point and the total
in litres with no decimals. High and low alarms are required at 18 l/m and 2 l/m
respectively. The instrument is then programmed as follows:
CAL00 0 No Pulse Output
CAL01 00020 Span (Whole Numbers)
CAL02 5380 Span (Decimals)
CAL03 0.05 Cutoff Point as a fraction of Span
CAL04 1 Rate decimal position
CAL05 1 Timebase
CAL06 01 Filter disabled
CAL07 0 Total decimal position
CAL08 0001 Total Conversion (set to 1.0000)
CAL09 0000 Total Conversion (decimals)
CAL10 00002 Low Alarm
CAL11 0000 Low Alarm
CAL12 00018 High Alarm
CAL13 0000 High Alarm
CAL14 0 Linear Input
CAL15 xxxx Accumulated Totals
SOFT 202A1.11 Software Version