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Analogue interfaces
Zelio Analog
4
Converters for thermocouples and Pt100 probes
Voltage/current converters
The Zelio Analog range of converters is designed to convert signals emitted by
sensors or electrical measurements into standard electrical signals which are
compatible with automation platforms, controllers (thermal processes, speed, …).
They also allow the connection distance between a sensor and the measurement
acquisition device to be increased: for example between a thermocouple and a
programmable controller.
Conforming to IEC standards, UL and CSA certified, these converters are suitable
for universal use.
Measurement signals for thermocouples and Pt100 probes
The voltages induced by thermocouples vary between 10 and 80
m
V/°C, Pt100
probes (100 ohms at 0 °C) produce about 0.5 mV/°C, with measurement currents of
1 mA. Depending on the sensor, the signal to be measured ranges from a few
m
V
(thermocouple) to 250 and 700 mV for a Pt100 probe.
It is therefore difficult to transmit these low level signals over long electric lines
without encountering problems of interference, signal reduction or errors.
Connecting Zelio Analog converters close to the sensors resolves these problems :
4-20 mA current loops transmitted over a long distance are less sensitive to
interference than low level voltage signals from sensors,
signal reductions during transmission (resistance) of voltages do not occur,
the cables used to connect the converters to process equipment (programmable
controllers) are standard cables, which are more cost effective than extension cables
or compensation cables suitable for low level signals for Pt100 probes or
thermocouples.
Presentation
The Zelio Analog range
The Zelio Analog range has been developed both to take account of the most
common applications and to ensure great simplicity of installation:
pre-set input and output scales, requiring no adjustment
outputs protected against reverse polarity, overvoltage and short-circuits
c
24 V power supply
sealable protective cover
rail mounting and screw fixing onto mounting plate
LED indicator on the front panel
input and output selector switches on the front panel
output with fallback value if no input signal is present (due to failure of a sensor, for
example).
The Zelio Analog converter range is divided into four families:
Converters for J and K type thermocouples:
RMT J/K
Universal converters for Pt100 probes:
RMP T
p
0
Optimum converters for Pt100 probes:
RMP T
p
3
Universal voltage/current converters:
RMC
.
Converters for J and K type thermocouples
Thermocouples, which consist of two metals with different thermo-electric
characteristics, produce a voltage that varies according to temperature. This voltage
is transmitted to the Zelio Analog converter which converts it to a standard signal.
Converters for thermocouples have cold junction compensation to allow detection of
measurement errors induced by the connection to the device itself.
Converters for J and K type thermocouples have :
for inputs, a pre-set temperature range, depending on the model:
Type J: 0...150 °C, 0...300 °C, 0...600 °C
Type K: 0...600 °C, 0...1200 °C.
for outputs, a switchable signal:
0...10 V, 0... 20 mA, 4... 20 mA.
-
-
-
b
b
b
b
b
b
b
b
b
b
b
b
b
v
v
b
v
RMT J40BD
108999
RMT K90BD
108997
Characteristics :
pages 62 and 63
References :
page 64
Dimensions :
page 65
Schemes :
page 65
Presentation
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