WATLOWMLS300 Series User’s Guide

Manual Contents

This manual describes how to install, setup, and operate a 

MLS316 or MLS332 controller. Each chapter covers a 

different aspect of your control system and may apply to 

different users. The following describes each chapter’s 

purpose.

• Chapter 1: System Overview. Provides a component list 

and summary of features for the MLS300 controllers. 

• Chapter 2: Installation. Provides detailed instructions 

on installing the MLS300 controller and its peripherals.

• Chapter 3: Using the MLS300. Provides an overview of 

operator displays used for system monitoring and job 

selection.

• Chapter 4: Setup. Provides detailed descriptions of all 

menus and menu options for controller setup.

• Chapter 5: Extruder Options. Explains the additional 

features on an MLS300 controller equipped with Extruder 

Control Firmware.

• Chapter 6: Enhanced Features. Describes process 

variable retransmit, ratio, differential and cascade control 

features available with the enhanced features option.

• Chapter 7: Ramp/Soak. Explains how to setup and use 

the features of the ramp/soak option.

• Chapter 8: Tuning and Control. Describes available 

control algorithms and provides suggestions for 

applications.

• Chapter 9: Troubleshooting and Reconfiguring.

Includes troubleshooting, upgrading and reconfiguring 

procedures for technical personnel.

• Chapter 10: Linear Scaling Examples. Provides an 

example configuring a pressure sensor, a flow sensor, and 

an encoder using linear scaling.

• Chapter 11: Specifications. Lists detailed specifications 

of the controller and optional components.

Getting Started

The following sections provide information regarding product 

features, technical descriptions, safety requirements, and 

preparation for operation.

These symbols are used throughout this manual:

DANGER! Indicates potential for serious injury or loss

of human life.

WARNING! Indicates possible damage to property or

equipment.

NOTE! Indicates pertinent information in order to

proceed.

Initial Inspection

Accessories may or may not be shipped in the same container 

as the MLS300, depending upon their size. Check the 

shipping invoice carefully against the contents received in all 

boxes.

Product Features

The MLS300 series controllers provide 16 or 32 fully 

independent loops of PID control. When used as a stand-alone 

controller, you may operate the MLS300 via the two-line 16-

character display and touch keypad. You can also use it as the 

key element in a computer-supervised data acquisition and 

control system; the MLS300 can be locally or remotely 

controlled via an EIA/RS-232 or EIA/RS-485 serial 

communications interface. 

The MLS300 features include:

• Direct Connection of Mixed Thermocouple Sensors: 

Connect most thermocouples to the controller with no 

hardware modifications. Thermocouple inputs feature 

reference junction compensation, linearization, process 

variable offset calibration to correct for sensor 

inaccuracies, detection of broken, shorted or reversed 

thermocouples, and a choice of Fahrenheit or Celsius 

display.

• CIM300 Input Option: The CIM300 input module 

provides high density sensor termination with a smaller 

installation footprint and faster installation.

• Accepts Resistive Temperature Detectors (RTDs): Use 

3-wire, 100 ohm, platinum, DIN-curve sensors with two 

choices for range and precision of measurements. (To use 

this input, order a MLS316 or MLS332 controller with 

scaling resistors.)

• Automatic Scaling for Linear Analog Inputs: The 

MLS300 series automatically scales linear inputs used 

with other industrial process sensors. Enter two points, 

and all input values are automatically scaled in your units. 

Scaling resistors must be installed.

• Dual Outputs: The MLS300 series includes both heat 

and cool outputs for up to 16 loops. Independent control 

parameters are provided for each output.

• Independently Selectable Control and Output Modes:

You can set each control output to ON/OFF, Time 

Proportioning, Serial DAC, or Distributed Zero Crossing 

mode. Set up to two outputs per loop for ON/OFF, P, PI, 

or PID control with reverse or direct action.

• Control Outputs: Set high/low deviation and high/low 

process limits to operate digital outputs as on/off control 

functions or alarms.

• Flexible Alarm Outputs: Independently set high/low 

process alarms and a high/low deviation band alarm for 

each loop. Alarms can activate a digital output by 

themselves, or they can be grouped with other alarms to 

activate an output. 

• Global Alarm Output: When any alarm is triggered, the 

Global Alarm Output is also triggered, and it stays on until 

you acknowledge it.

• CPU Watchdog: The MLS300 series CPU watchdog 

timer output notifies you of system failure. You can use it 

to hold a relay closed while the controller is running, so 

you are notified if the microprocessor shuts down.

• Front Panel or Computer Operation: Set up and run the