METSO IOP304 high-performance Thermocouple (TC) / Millivolt (mV) Input Module

The Metso IOP304 (Part No. 181503 / 69230I304A) is a high-performance Thermocouple (TC) / Millivolt (mV) Input Module within the maxPAC I/O family, used in the Metso DNA and maxDNA Distributed Control Systems.

It is specifically designed for high-density, high-precision temperature monitoring in industrial environments.

1. Introduction

The IOP304 is a 16-channel isolated analog input module. It is engineered to interface directly with thermocouples or low-level voltage (mV) signals without the need for external signal converters.

A key feature of this module is its ability to handle Cold Junction Compensation (CJC) internally when equipped with the appropriate thermistor, ensuring accurate temperature readings even as the ambient cabinet temperature changes.

2. Technical Parameter Table

3. Related Models

The IOP304 is part of the “300-series” high-density I/O lineup:

IOP302: 16-channel Analog Input (4–20 mA).

IOP301: Isolated Analog Input Module.

IOP303: 8-channel RTD Input Module (Resistance-based temperature).

IOT300A: The standard terminal base unit used to house the IOP304.

4. Application Cases

Thermal Power Plants: Monitoring boiler tube temperatures and exhaust gas temperatures.

Pulp & Paper: Tracking temperature profiles in chemical recovery boilers and lime kilns.

Metals & Mining: Used in furnace and smelting operations where high-temperature thermocouples are standard.

Safety Interlocks: Providing temperature data for emergency shutdown (ESD) logic in high-heat processes.

IOP304

5. Product Advantages and Features

Built-in CJC: By installing a thermistor (Part No. 074566) directly into the front connectors, the module performs automatic cold junction compensation, simplifying field wiring.

High Density: Processes 16 channels in a single rack slot, making it one of the most space-efficient temperature modules in the DNA system.

Flexible Redundancy: Supports “Common I/O” or “Redundant I/O” configurations via internal jumpers (W2), allowing for high-availability setups.

Legacy Compatibility: Includes a jumper (W6) to act as a replacement for older Model 564 modules, facilitating system migrations.

Deterministic Filtering: Hardware jumpers allow the selection of 50 Hz or 60 Hz line frequency rejection to eliminate electrical noise from the power grid.

6. Other Models in the Same Series

The IOP304 is a cornerstone of the maxPAC / Metso DNA architecture:

DPU-MR / PDP601: The central processing units that manage IOP304 data.

IOP331: 16-channel Digital Input (48V).

IOP351: 16-channel Relay Output.

IOP320: 8-channel Analog Output.