Mantracourt ALA5 User Manual
ALA5 2-Wire 4-20mA ATEX
Load Cell Amplifier
ICA5ATEX Strain Gauge or Load Cell Analogue Amplifier Mounted Inside
an In-Line Stainless Steel Enclosure (ILEATEX)
User Manual
MICRON METERS
www.micronmeters.com
metersinfo@micronmeters.com
Mantracourt Electronics Limited ALA5, ILEAtex and ICA5Atex User Manual
1
Contents
Chapter 1 The ALA5 ..................................................................................................................... 2
Chapter 2: Installing the ALA5 ........................................................................................................ 2
Pre Installation ............................................................................................................................ 2
Connections: ............................................................................................................................... 3
Standard cable: ........................................................................................................................... 3
Table 1 ..................................................................................................................................... 3
Cable colour code: ....................................................................................................................... 4
Alternative Cable types .................................................................................................................. 4
Figure 2.1 Connection Details for the ALA5 .......................................................................................... 4
Output Connections ...................................................................................................................... 5
Output Shunt Resistance Formula ..................................................................................................... 5
Chapter 3: Calibration .................................................................................................................. 5
Chapter 4: Changing the Gain and Offset Ranges................................................................................. 6
Figure 4.1 .................................................................................................................................. 6
Calculating the Gain Resistor (R2) ..................................................................................................... 7
Offset Resistor (R1) ...................................................................................................................... 7
Chapter 5: OEM Customers ............................................................................................................ 7
The ICA5ATEX Connections .............................................................................................................. 8
ILEATEX Enclosure ........................................................................................................................ 8
Chapter 6: Specifications .............................................................................................................. 9
Table 6.1 ICA5ATEX – 4-20mA 2 wire Specifications ................................................................................ 9
Table 6.2 ILEATEX Enclosure Specifications .......................................................................................... 9
Environmental Approvals ............................................................................................................... 10
Appendix A: Special Conditions of Safe Use ...................................................................................... 10
ATEX Marking: ............................................................................................................................ 11
EU DECLARATION OF CONFORMITY ................................................................................................. 12
EU ATTESTATION OF CONFORMITY ................................................................................................. 13
EU ATTESTATION OF CONFORMITY ................................................................................................. 14
ALA5 Certificate: ........................................................................................................................ 15
ICA5ATEX Certificate: ................................................................................................................. 19
Mantracourt Electronics Limited ALA5, ILEAtex and ICA5Atex User Manual
2
Chapter 1 The ALA5
The ALA5 is an ATEX certified (intrinsic safety) 2-wire 4-20mA amplifier providing a wide range of signal conditioning
for Strain Gauges, Load Cells, Pressure and Torque Transducers.
Combining the ICA5ATEX miniature loadcell amplifier with the stainless steel ILEATEX enclosure produces a
compact, robust and certified in-line amplifier suitable for use in zones 0, 1, and 2 in hazardous locations.
The ICA5ATEX is designed for a 1k bridge, however, 350R can be used at the expense of noise and drift
performance.
Please note: the ICA5ATEX amplifier’s output is uni-polar output i.e. zero strain input = 4mA and full range input =
20mA output.
Sensitivity adjustment, between 0.5 mV/V and 55 mV/V is achieved by a combination of the SPAN (gain) resistor R2
(see fig 4.1) and associated fine adjustment by potentiometer. Chapter 4 gives details of how to calculate a new
value for R2 to suit loadcell outputs other than the factory set 2.5mV/V.
Similarly transducer ZERO can be compensated for in the module. This adjustment is to compensate for slight errors
in the strain gauge and not to offset tare. The value of R1 (see fig 4.1) can be modified to increase the trim range of
the zero point (see chapter 4).
Chapter 2: Installing the ALA5
Pre Installation
Carefully remove the ALA5 unit from its shipment box. Check that the unit is complete and undamaged.
The ALA5 can be installed in any industrial environment providing the following limits and ATEX conditions of use
are met.
Please refer to Appendix A – ‘Special conditions of safe use’
Operating Temperature
-40ºC to +85ºC
Humidity
95% non condensing
Storage temperature
-40ºC to +85ºC
II 1 G Ex ia IIC T4
Tamb = -40°C to +85°C
CE0891 TRaC10ATEX11247X
Ui= 28V, Ii = 100mA, Pi = 0.7W
Co = 33nF, Lo = 3mH
For an explanation of the ATEX conditions of use see Appendix A
Mantracourt Electronics Limited ALA5, ILEAtex and ICA5Atex User Manual
3
Figure 2.1 Dimensions
Connections:
The ALA5 is supplied pre-wired with 2-core screened cable for the supply/signal and 4-core screened cable for the
loadcell connections.
If installing into a hazardous zone, the ALA5 must be connected via an approved ATEX Barrier with the following
parameters:
Uo = 28V, Io = 100mA, Po = 0.7W, Barrier Impedance 300Ω.
These are maximum values, actual barrier parameters will vary. However, the barrier impedance is not permitted to
change.
Please refer to Appendix A – ‘Special conditions of safe use’
Two examples of suitable barriers are:
MTL7706+ (passive Zener diode type with active current limit) manufactured by MTL Instruments
KFD2-STC4-EX1/2 (3-way isolated type) manufactured by Pepperl and Fuchs
Standard cable:
IMPORTANT NOTE: The cables factory-fitted to the ALA5 (see table 1) limit the operating temperature range to
-25°C to +70°C.
Table 1
Country
Supplier
Part No
Description
UK
Farnell
1218651
Loadcell cable 1m: Belden 8132
Twin twisted pair cable (28 AWG)
100% overall foil shield + 65% tinned copper braided outer shield
O.D. 5.6mm
Capacitance: core to core 33 pF/m & core to shield 61 pF/m
Worst case capacitance: 224pF/m – see note 1
Temperature range: -30°C to +80°C
UK
Farnell
3855636
(per metre)
798-551
(100m reel)
Output cable 5m: Van Damme 268006C
Single twisted pair cable (24 AWG) + 95% tinned copper braided
shield
O.D. 4.85mm
Capacitance: core to core 100 pF/m & core to shield 165 pF/m
Worst case capacitance: 197pF/m – see note 1
Temperature range: -25°C to +70°C
Note 1: The maximum capacitance, Cc, can be taken as the capacitance between all cores connected together and
the screen (Annex C of the installations standard EN60079-14). A safety margin of +10% has been added.
Mantracourt Electronics Limited ALA5, ILEAtex and ICA5Atex User Manual
4
The ground connection conductor should have sufficient cross-sectional area to ensure a low impedance path to
attenuate RF interference.
Cable colour code:
Power/signal
Red
Supply +
Green
Com
Loadcell
Orange/White
+Exc
White/Orange
-Exc
Blue/White
+In
White/Blue
-In
Alternative Cable types
The type of cable used should be suitable for use in the hazardous area with particular regard to the certified -40°C
to +85°C temperature range of the ALA5.
The cable should comprise twin twisted pairs of cables – four-core for the loadcell and a single pair for the
power/signal.
Each cable should have an overall braid to ensure a good EMC seal with the glands on the ALA5.
Figure 2.1 Connection Details for the ALA5
The barrier limits the amount of electrical energy that can be transferred into the hazardous area thereby
preventing the ignition of a flammable atmosphere in the event of a fault condition occurring.
A simple passive barrier is shown above but this can be replaced by an isolated barrier to avoid ground loops that
may affect measurement accuracy and stability. These devices provide three-way isolation between power, input
and output.
The ALA5 is supplied with a 1m input cable and a 5m output cable. If the cables are too short for a particular
installation, they can be replaced with longer lengths or joined provided that an ATEX approved junction box is used
and the conditions set out below are satisfied. Excessively long leads, particularly the load cell cable may cause
noise and stability problems.
IMPORTANT NOTE: In order to remain ATEX compliant, the total amount of capacitance that can be connected
to the ALA5 enclosure (Co) must not exceed 33nF (0.033uF). This value must include the total cable
capacitance and the Ci value of the barrier supplying the unit. If the installation includes any ATEX junction
boxes their Ci values must also be included.
As an example, the maximum length for the output cable specified in table 1 will be:
(33nF – 224pF)/197pF = 166.4m (multiply the pF/m figure given in table 1 by the length in metres to obtain the
total capacitance of each cable)
Mantracourt Electronics Limited ALA5, ILEAtex and ICA5Atex User Manual
5
Please refer to Appendix A – ‘Special conditions of safe use’
For special cable types e.g. high temperature, armoured etc. please contact Mantracourt Electronics.
Output Connections
The ICA5ATEX analogue output is 4 to 20mA. The power and signal are combined in a single pair cable, simplifying
installation.
N.B. Neither connection to the output load is electrically common to the load cell.
The following formula gives the suitable range of shunt resistance for low supply voltage operation.
Output Shunt Resistance Formula
The shunt resistance must be less than: ((V supply -9) / 20mA) – Rwiring
e.g. assuming 10 Ohms wiring resistance and 24V supply:
Max shunt resistance = ((24 - 9) / 0.02) –10 = 740 Ohms
Chapter 3: Calibration
In order to calibrate the ALA5 the cover of the enclosure must be removed as follows:
Mechanical tools required: 1.5mm hex key, 14mm AF spanner and flat-blade screwdriver, maximum width 1.5mm.
1. Remove the two grub screws using a
1.5mm hex key
2. Loosen the gland furthest away from the
grub screw holes using a 14mm AF
spanner.
Mantracourt Electronics Limited ALA5, ILEAtex and ICA5Atex User Manual
6
3. Gently ease the base out of the cover
ensuring that the cable slides through
the loosened gland to avoid any strain on
the internal connections.
4. The ICA5ATEX amplifier will now be
exposed allowing access to the two
trimming potentiometers.
Calibration:
1. Apply the low calibration conditions (weight, force or mV/V). Set the output to 4mA using the Zero
potentiometer.
2. Apply the known high calibration conditions (ideally between 75% and full scale) and adjust the Span
potentiometer to give the required output current for the known input.
i.e. 16mA for 4-20mA final calibration with 75% input or 20mA if 100% input.
When re-assembling the ALA5 it is imperative that the ‘O’ is fitted correctly and the cable gland re-tightened to
maintain a gas-tight seal.
Chapter 4: Changing the Gain and Offset Ranges
The ICA5ATEX amplifier is supplied un-calibrated but optimized for a sensitivity of 2.5mV/V with a 1k bridge.
To accommodate other sensitivities the gain resistor, ‘R2’ (see below) can be changed to a value derived from the
following formula.
Figure 4.1
N.B. a high quality resistor (e.g. 1% 25-50 ppm metal film) should be used for best performance. It may be necessary
to use an E96 value for optimum trim range: -
Mantracourt Electronics Limited ALA5, ILEAtex and ICA5Atex User Manual
7
Calculating the Gain Resistor (R2)
10
)/(
2.1069
2
VexcVmV
R
k Ohms
Where
VmV /
is the sensitivity of the load cell (in mV/V), Vexc is the excitation voltage (in volts).
The following table gives calculated values of Vexc for various standard load cell impedances:
Load Cell Impedance
Excitation voltage (Vexc)
350
0.53
700
0.87
1000
1.08
1400
1.29
2000
1.51
5000
1.97
e.g. For a 2.5mV/V 1000 Ohm load cell : R2 = 386k Ohms – use 390k (nearest preferred value)
Use the following formulae to calculate the excitation voltage for cell impedances not given in the table:
6exp10762.4)/1(1Rcell
Rx
Ohms
1300
5.2RxRx
Vexc
Volts
e.g. for a 500 Ohm load cell:
Rx = 498.8 Ohms
Excitation Voltage, Vexc = 0.693V
Offset Resistor (R1)
The value of R1 can be changed to offset the zero point, if outside the normal trimming range (±2% FS).
Its value will also depend on the impedance of the load cell. The factory-fitted value, 180k is optimised for a 1000
Ohm cell.
If a 350 Ohm cell is used, R1 should be reduced to 30k to achieve a trim range of ±2% FS
Chapter 5: OEM Customers
IMPORTANT: OEM customers must hold a notified body Quality Assurance Notification (QAN)
if the ICA5ATEX is to be installed into a Mantracourt ATEX approved ‘generic’ enclosure.
If installed into a non-ATEX approved enclosure, the whole assembly must be submitted for
ATEX certification by an appropriate body.
Please refer to Appendix A – ‘Special conditions of safe use’
Mantracourt Electronics Limited ALA5, ILEAtex and ICA5Atex User Manual
8
The ICA5ATEX amplifier is designed to fit into a pocket in a certified loadcell. Use the 2.1mm hole to secure the unit
and to provide a good ground connection.
The mounting hole will accept an M2 screw or American equivalent #0-80.
Important Note: DO NOT USE #2 screw size.
Take care when soldering cables to the pads. Use a temperature controlled soldering iron set to a maximum 330 ºC,
for no longer than 2 seconds per pad. Excessive heat or increased soldering time may result in damage to the PCB.
See fig 2.1 for recommended screen connections.
The ICA5ATEX Connections:
The power supply should be between 9 and 28V and must be connected through an ATEX approved barrier if
installing into a hazardous area.
ILEATEX Enclosure
Package Contents
EMC ‘O’ ring
enclosure body
enclosure Cover
2 x EMC cable glands PG7/20 TPI 14mm AF
2 x grub screws
1 x M2 spring washer
1 x M2 cylindrical spacer
M2 x 12mm cap screw
Ensure that the ‘O’ ring is fitted to the body.
Please refer to Appendix A – ‘Special conditions of safe use’
Body
Cover
Loading...