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RT285U is designed for wide use. It is equipped with a 4-digit LED display, universal input for Pt100, Pt1000, PTC, 6 types of thermocouples, as well as for linear current, voltage and resistance signals from external converters and can have up to 5 programmable relay control/alarm outputs and 2 analog repeaters. The device has a built-in self-diagnostics and self-calibration circuit, the ability to manually correct the reading, as well as program compensation for the line resistance and the temperature of the “cold” end. There is possibility to enter a custom function (linearization). The correspondence of the input and display with a linear input, the decimal point, the unit of measurement are also programmable. Thanks to the universal input, the interface, the variety of housings, as well as the very good quality-price ratio, the RT285U finds extremely wide industrial application.
The RT285U is widely used in industrial processes requiring precise temperature control. Thanks to its universal input and variety of housings, the controller is suitable for:
| Input (programmable) | |
| Pt100 (w=1.385); 3-wire (DIN IEC 60751) | -100…850 °C |
| Pt1000 (w=1.385); 3-wire (DIN IEC 60751) | -100…600 °C |
| PTC (1k at 25 °C); 3-wire (KT and KTY based) | -50…150 °C |
| PTC (2k at 25 °C); 3-wire (KT and KTY based) | -50…150 °C |
| Thermocouple “T” (DIN IEC 60584) | -40…400 °C |
| Thermocouple “J” (DIN IEC 60584) | -20…1000 °C |
| Thermocouple “K” (DIN IEC 60584) | -20…1300 °C |
| Thermocouple “S” (DIN IEC 60584) | 0…1700 °C |
| Thermocouple “R” (DIN IEC 60584) | 0…1700 °C |
| Thermocouple “B” (DIN IEC 60584) | 100…1800 °C |
| Linear voltage 0…10 V | -1999…9999, programmable |
| Linear current 0(4)…20 mA | -1999…9999, programmable |
| Linear resistive 0…1 kΩ | -1999…9999, programmable |
| Custom linear (option) (1) | -1999…9999, programmable |
| Linearization | up to 27 points |
| Two-wire external transmitter | 4…20 mA (2) |
| Manual input offset | programmable |
| Input type selection | programmable |
| Decimal point selection | programmable |
| Temperature measurement unit | °C or °F, programmable |
| Outputs (up to 5 relay outputs) | |
| Relay electromechanical | 5A/250V w/ NO/NC or NO contact |
| Solid state relay (SSR) | 1A/250VAC |
| MOS gate | 0.1A/60V, optically isolated |
| Output for external SSR | 5…24 V, 30 mA |
| Control algorithm | ON/OFF |
| Set point | within input range limits |
| Alarms | programmable |
| Analog output | 4(0)…20 mA, 0…10 V |
| Serial interface | RS485, isolated |
| Accuracy | |
| Measurement error | 0,3% (3) from span |
| Temperature drift | 0.02% from span for 1 °C |
| Cold junction compensation | automatic, -10…80 °C |
| RTD line compensation | automatic, up to 2 х 25 Ω |
| Power supply | |
| Mains supply voltage | 230 VAC или 115 VAC |
| SMPS voltage | 90…250 V |
| Isolated low voltage | 12…24 V или 24 VAC |
| Non-isolated low voltage | 12…24 V |
| External mains transformer | 9(12) VAC |
| Consumption | max. 2 VA |
| Indication and controls | |
| Digital display | 4 LED indicators |
| LEDs | 5 LEDs for output state |
| Keyboard | 3 membrane keys |
| Operating conditions | |
| Ambient temperature | -10…65 °C |
| Ambient humidity | 0…85 %RH |
(1) Instead of linear current
(2) Provides loop supply voltage – 24 VDC (only with isolated power supply to the device).
(3) 0.5% for TCs “S”, “R”, and “B”
