Name: DOFONICS Model ME900 Temperature Controller for Marine Purifier
Brand: JIEXI Fast Marine Service(Guangzhou) Co., Ltd
SKU: ME900

Description

Key Specifications

Sampling Time	0.5 seconds (ME900) / 1 second (ME901)
Measurement Accuracy	±0.3% of displayed value + 1 digit
Control Method	PID control (with auto-tune), also supports ON/OFF, P, PD, PI modes
Control Outputs	Relay (1a contact), SSR drive voltage pulse (0/12V DC), 4–20 mA current, Triac
Alarm Outputs	Max. 3 points per channel (temperature alarm, HBA, LBA)
Memory Blocks	8 blocks for setpoint/PID parameter storage
Communication	RS-232C / RS-422A / RS-485 (MODBUS protocol, optional)
Power Supply	100–240V AC / 24V AC / 24V DC
Ambient Temperature	0 to 50°C
Weight	Approx. 560 g
Safety Standards	UL 61010-1, CSA C22.2 No. 61010-1, CE Marking (LVD EN61010-1, EMC EN61326-1), RCM

Overview

DOFONICS ME900 is a multi-loop digital temperature controller based on a microprocessor, specifically designed for the precise temperature regulation of shipboard centrifugal purifiers (oil separators). It is a compact, panel-mounted instrument (96×96×100 mm) that provides precise PID control for the preheating of oil, ensuring that the fuel or lubricating oil entering the purifier bowl remains at the optimal temperature for effective separation.

Primary Functions

Multi-Channel Temperature Measurement & Control：The ME900 supports up to 4 channels (ME900) or 8 channels (ME901) of independent temperature control on a single controller, allowing simultaneous monitoring of multiple heating zones in the purifier system (e.g., heater outlet, purifier inlet, return line).

PID Control with Auto-Tuning： Implements advanced PID (Proportional-Integral-Derivative) control algorithm with automatic tuning (auto-tune) function, which automatically calculates optimal PID parameters to minimize overshoot and stabilize temperature quickly.

Heating/Cooling Dual Control： Supports both heating and cooling PID control modes, enabling the controller to modulate steam heating valves or electric heaters as well as cooling media if required.

Alarm Functions: Provides up to 3 alarm outputs per channel, including：

- Temperature alarm (high/low deviation alarm)
- Heater break alarm (HBA) — detects open-circuit or failure of the heating element
- Control loop break alarm (LBA) — detects sensor or control loop failure

Multi-Memory Area: Stores up to 8 memory blocks for different setpoints and PID parameters, allowing quick switching between different fuel grades (HFO, MDO, LO) without manual reconfiguration.

Digital Communication (Optional): Supports RS-232C, RS-422A, or RS-485 communication with MODBUS protocol, enabling integration with the ship's centralized automation system or the purifier's main control unit (e.g., EPC-50).

Working Principle

The ME900 operates on a closed-loop feedback control principle:

1. Sensing: A temperature sensor (thermocouple type K, J, T, S, R, etc., or RTD Pt100/JPt100) is installed in the oil pipeline at the purifier inlet. It continuously measures the actual oil temperature and sends the signal to the ME900 controller.

2. Signal Processing: The controller's input circuit converts the sensor signal (thermocouple voltage or RTD resistance) into a digital temperature value. Measurement accuracy is ±0.3% of displayed value + 1 digit.

3. Comparison: The measured temperature (Process Value, PV) is compared against the operator-set setpoint (Set Value, SV).

4. PID Computation: The controller calculates the required control output using the PID algorithm:

P (Proportional): Reacts to the current error magnitude
I (Integral): Eliminates steady-state offset over time
D (Derivative): Dampens rapid temperature fluctuations

5. Actuation: The controller outputs a control signal to the final control element:

Relay contact output (1a contact) — for on/off control of electric heaters
Voltage pulse output (0/12V DC) — for SSR (Solid State Relay) driving
Current output (0–20 mA or 4–20 mA DC) — for modulating steam control valves
Triac output — for direct thyristor control

6. Stabilization: The control loop continuously adjusts the heating power to maintain the oil temperature at the setpoint with minimal deviation.

Application Scenarios

Application	Oil Type	Typical Setpoint	ME900 Configuration
Heavy Fuel Oil (HFO) Purification	HFO	90–98°C	Pt100 input, 4–20 mA output to steam valve, high-temp alarm at 100°C
Marine Diesel Oil (MDO) Purification	MDO	40–50°C	Pt100 input, SSR drive to electric heater, low-temp interlock at 35°C
Lubricating Oil (LO) Purification	LO	85–95°C	Pt100 input, relay output, heater break alarm enabled
Multi-Fuel Changeover	HFO ↔ MDO	Switchable	Use memory blocks 1–4 for different fuel recipes

Advantages

Compact Multi-Channel Design: One ME900 controller can replace multiple single-loop controllers, saving panel space in the engine room.

Fast Sampling (0.5 sec): Ensures rapid response to temperature fluctuations caused by changes in oil flow rate or steam pressure.

Heater Break Alarm: Critical for electric heaters — immediately detects heater element failure and alerts the engineer.

MODBUS Communication: Allows remote monitoring and control from the engine control room (ECR) or integrated bridge system.

Rugged Construction: Designed for industrial environments with ambient temperatures up to 50°C, suitable for engine room conditions.

DOFONICS Model ME900 Temperature Controller for Marine Purifier

Description

Key Specifications

Working Principle

The ME900 operates on a closed-loop feedback control principle:

Application Scenarios

Advantages

Compact Multi-Channel Design: One ME900 controller can replace multiple single-loop controllers, saving panel space in the engine room.

Fast Sampling (0.5 sec): Ensures rapid response to temperature fluctuations caused by changes in oil flow rate or steam pressure.

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DOFONICS Model ME900 Temperature Controller for Marine Purifier

Description

Key Specifications

Working Principle

The ME900 operates on a closed-loop feedback control principle:

Application Scenarios

Advantages Compact Multi-Channel Design: One ME900 controller can replace multiple single-loop controllers, saving panel space in the engine room.Fast Sampling (0.5 sec): Ensures rapid response to temperature fluctuations caused by changes in oil flow rate or steam pressure.

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CONTACT US

Advantages

Compact Multi-Channel Design: One ME900 controller can replace multiple single-loop controllers, saving panel space in the engine room.

Fast Sampling (0.5 sec): Ensures rapid response to temperature fluctuations caused by changes in oil flow rate or steam pressure.