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Pt100 Transmitters
HD 788TR1 - HD 786TR1 - HD 988TR1 - HD 988TR2
HD 788TR1, HD 786TR1, HD 988TR1 and HD 988TR2 are 4-20 mA transmitters with a microprocessor, configurable for Pt100 Platinum temperature sensors. They convert the temperature variations found with any standard Pt100 sensor (100W at 0°C) into a linear current signal with two leads in the field 4-20 mA. Linearization with a digital technique allows excellent precision and stability to be obtained. The user can set the 4-20 mA output (or 20-4 mA) in any temperature range within the field -200...+650°C, with a minimum amplitude of 25°C; it may be simply reprogrammed by pressing a key, without any need to regulate jumpers, potentiometers, software, etc.
A led indicates any alarm situations (temperature outside the set range, broken or short-circuiting sensor) and assists the user in the programming phase. The transmitters are also protected against inversions of polarity. The HD 788TR1 is specifically designed for installing in type DIN B connecting heads, while the HD 988TR1 and HD 988TR2 are suitable for fitting in containers with a 35 mm DIN bar connection. As well as the 4-20 mA output, the HD 988TR2 has a convenient 31.2 digit display (height 10 mm) which allows the display of the measured temperature. Suitable for fitting on the wall.
HD 788TR1 - HD 786TR1 - HD 988TR1 - HD 988TR2
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Pt100 Transmitters
HD 688T
Output analogue signal: 0-20 mA / 4-20 mA / 0-10 Vdc.
The HD 688T transmitter is built inside a 2-module DIN box for 35 mm asymmetric guide. The module turns the signal coming from a Pt100 into an analogue signal that can be sorted out through a jumper connection between 0-20 mA, 4÷20 mA, 0÷10 V. The signal is galvanically separated among input, output and power supply. The 3-way insulation of the module allows the prevention of reciprocal influences in the presence of various measuring circuits.
The HD 688T transmitter is made up of the following stages:- input stage including linearization of the curves and equalization of the resistance of the line cable (3 wires) of Pt100, conversion from voltage into frequency;- universal output stage through jumper connection, conversion from frequency into voltage;- power supply stage.
The configuration of the measuring range or the output signal can be modified at any time, an outstanding feature being that any variation does not involve the need to calibrate the transmitter again.
HD 688T
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