Month: July 2026

Typical Applications

• Foodservice equipment

• Industrial machinery

• Medical equipment

• Packaging equipment

• Plastics processing equipment

Specifications

Controller

• Microprocessor based, limit controller

• Customer defined hysteresis, model number

dependent

• High limit, factory selectable

• Automatic reset on power loss

• Input filter time: 1 second

Thermocouple Sensor Input

• Ungrounded

• Type J and K thermocouple types

• >10 MΩ input impedance

Input Accuracy Span Range

• Type J: 0 to 764°F (-18 to 406°C)

• Type K: 0 to 999°F (-18 to 537°C)

• Calibration accuracy: ±6°C, ±1° at standard conditions

and actual calibration ambient

• Temperature stability: ±0.3 degree per degree change

in ambient

Allowable Operating Ranges

• Type J: 32 to 626°F (0 to 330°C)

• Type K: 32 to 820°F (0 to 438°C)

Output Types

• Electromechanical relay, Form A, minimum load

current: 100mA, 8A resistive load, 120VA pilot duty,

120/240VAC maximum, inductive, electrical life 6,000

cycles at rated current

Terminals

• 0.25 in. (6.4 mm) quick connect, push-on terminals

Agency Approvals

• UL® / EN 60730-1, 2, 9 automatic electronic controls

for household and similar use. File #E43684

• UL® 1998 software review class B

• W.E.E.E.; CE – see Declaration of Conformity

• RoHS directive (2011-65-EU)

As manufacturers are required to meet tighter safety

standards, Watlow has addressed this need with its new

SERIES LS safety limit. This new limit meets UL® 1998

and EN 60730 safety requirements and will shut down

a system to prevent damage to equipment or injury to

personnel.

Watlow’s SERIES LS is recommended for any application

where control failure could cause the temperature of

the application to continue to increase resulting in large

product scrap costs, damage to system equipment or

potential fire hazard.

The SERIES LS provides increased safety due to the use

of a factory fixed set point, factory fixed hysteresis and

the use of redundant temperature sensors to protect

against a single point sensor failure. Either sensor can

initiate an overtemperature limit condition along with a

deviation between sensors greater than the process

comparison value.

Watlow’s new SERIES LS offers fixed limit set point

temperature values that are customer definable in the

product configuration part number. It is available with

a potted module design configuration and push-on,

quick connect spade terminals to provide the electrical

connections.

Specifications

Limit Controller

• Microprocessor-based limit controller

• Nominal switching hysteresis, typically 3°F (1.7°C)

• High or low limit, factory selectable

• Latching output requires manual reset upon over or

under temperature condition

• Manual or automatic reset on power loss, factory

selectable

• Internal front panel or external customer supplied

momentary reset switch

• Input filter time: 1 second

Operator Interface

• 4 digit, 7 segment LED displays, 0.28 in. (7 mm) high

• °F or °C indicator LED

• Alarm indicator LED

• Continuous turn, velocity sensitive rotary encoder for

set point adjustment

• Front panel SET/RESET

Standard Conditions for Specifications

• Rated line voltage, 50 to 60Hz, 0 to 90% RH

non-condensing, 15-minute warm-up

• Calibration ambient range: 77°F (25°C) ±3°C

Sensor Input

Thermocouple

• Grounded or ungrounded

• Type E, J, K, T thermocouple

• >10 MΩ input impedance

• 250 nV input referenced error per 1Ω source

resistance

RTD

• 2-wire platinum, 100Ω

• DIN-curve (0.00385 curve)

• 125μA nominal RTD excitation current

Input Accuracy Span Range

Type E: -328 to 1470°F (-200 to 800°C)

Type J: 32 to 1382°F (0 to 750°C)

Type K: -328 to 2282°F (-200 to 1250°C)

Type T: -328 to 662°F (-200 to 350°C)

RTD (DIN) -328 to 1472°F (-200 to 800°C)

Thermocouple Input

• Calibration accuracy: ±1% of input accuracy span,

±1° at standard conditions and actual calibration

ambient. Exception: Type T, ±2.4% of input accuracy

span for -328 to 32°F (-200 to 0°C)

• Temperature stability: ±0.3° per degree change in ambient

SERIES LV Features and Benefits

Adjustable set points

• Offers control flexibility

Four character LED display

• Improves set point selection accuracy

Multiple mounting options

• Minimizes installation time

High or low limit with auto or manual reset

• Provides application flexibility

Fahrenheit or Celsius operation with indication

• Offers application flexibility

Sensor break protection

• Provides positive system shutdown

Agency approvals

• Meets certification requirements/compliance

Microprocessor based technology

• Ensures accurate, repeatable control

Watlow’s family of microprocessor-based limit controllers

provides an economical solution for applications requiring

temperature limit control. Limits are available in a broad

range of packaging options, allowing selection of the best

version for an application. Limits are available with an

operator interface and can be ordered in 1/8 DIN-square

panel mount or DIN-rail mount design configurations.

The SERIES LV limit family incorporates a microprocessor

design platform. This design provides

significant

improvements in the performance, repeatability and

accuracy offered by Watlow’s current line of analog

limit controllers.

The variable SERIES LV limit includes an operator

interface for viewing and selecting the set point. A red,

four-character seven segment LED displays the set point.

Set point selection is made with a continuous turn rotary

encoder. Operating range temperature values are

customer defined in the product configuration

part number.

The limit controllers are factory mutual (FM) approved with

special UL® approval for the open board potted versions.

Watlow’s limit controllers include industry leading service

and support and are protected by a three-year warranty.

SERIES LF

Specifications

Limit Controller

• Microprocessor based, limit controller

• Nominal switching hysteresis, typically 3°F (1.7°C)

• High or low limit, factory selectable

• Latching output requires manual reset upon over or

under temperature condition

• Manual or automatic reset on power loss, factory

selectable

• External customer supplied momentary reset switch

• Input filter time: 1 second

Standard Conditions For Specifications

• Rated line voltage, 50 to 60Hz, 0 to 90% RH

non-condensing, 15-minute warm-up

• Calibration ambient range: 77°F (25°C) ±3°C

Sensor Input

Thermocouple

• Grounded or ungrounded

• Type E, J, K, T thermocouple

• >10 MΩ input impedance

• 250 nV input referenced error per 1Ω source resistance RTD

• 2-wire platinum, 100Ω

• DIN-curve (0.00385 curve)

• 125μA nominal RTD excitation current

Input Accuracy Span Range

Type E: -328 to 1470°F (-200 to 800°C)

Type J: 32 to 1382°F (0 to 750°C)

Type K: -328 to 2282°F (-200 to 1250°C)

Type T: -328 to 662°F (-200 to 350°C)

RTD (DIN) -328 to 1472°F (-200 to 800°C)

Thermocouple Input

• Calibration accuracy: ±1% of input accuracy span,

±1° at standard conditions and actual calibration

ambient. Exception: Type T, ±2.4% of input accuracy

span for -328 to 32°F (-200 to 0°C)

• Temperature stability: ±0.3° per degree change in ambient

RTD Input

• Calibration accuracy ±1% of input accuracy span

±1° at standard conditions and actual calibration ambient

• Temperature stability: ±0.2° per degree change in ambient

Features and Benefits

Fixed set points

• Provides tamper-proof operation

Multiple mounting options

• Minimizes installation time

High or low limit with auto or manual reset

• Provides application flexibility

Fahrenheit or Celsius operation with indication

• Offers application flexibility

Sensor break protection

• Provides positive system shutdown

Agency approvals

• Meets certification requirements/compliance

Microprocessor based technology

• Ensures accurate, repeatable control

Watlow’s family of microprocessor- based limit controllers

provide an economical solution for applications requiring

temperature limit control. Limits are available in a broad

range of packaging options, allowing selection of the best

version for an individual application. Controllers are

available without an operator interface and can be

ordered in square 1/8 DIN-panel mount, DIN-rail mount or

open board design configurations.

The SERIES LF limit family incorporates a microprocessor

design platform. This design provides significant

improvements in the performance, repeatability and

accuracy offered by Watlow’s current line of analog basic

temperature controllers.

The SERIES LF limit offers fixed set points and can be

supplied with or without an operator interface. Operating

set point temperature values are customer defined in the

product configuration

part number.

The LF limit controllers are factory mutual (FM) approved

with special UL® approval for the open board potted

versions. Watlow’s limit controllers include industry

leading service and support and are protected by a

three-year warranty.

EZ-ZONE RM

Additional Key Functions

• Configuration communication port (standard bus)

• Removable modules and connectors

• Ring lug and front-screw terminal options

• Profile ramp soak with 400 total steps

• Retransmit and remote set point input virtually inside

controller eliminating costs for input/output hardware

• User configuration settings can be stored and recalled

• Thermistor input

• Elevated operating range of 0 to 149°F (-18 to 65°C)

• UL® listed, CSA, CE, RoHS, W.E.E.E., FM,

SEMI F47-0200, Class 1, Div. 2 rating on selected

models

Common Specifications (Applies to all models)

Line Voltage/Power

• 20.4 to 30.8VAC/VDC, 50/60Hz ±5%

• Any external power supply used should comply with a

Class 2 or SELV rating (see specific module

specification listing for max. VA power consumption)

• Data retention upon power failure via non-volatile

memory

• Compliant with Semi F47-0200, Figure R1-1 voltage

sag requirements

Environment

• 0 to 149°F (-18 to 65°C) operating temperature

• -40 to 185°F (-40 to 85°C) storage temperature

• 0 to 90% RH, non-condensing

Functional Operating Range for RMC, RMH, RML

and RMS

Type J: -346 to 2192°F (-210 to 1200°C)

Type K: -454 to 2500°F (-270 to 1371°C)

Type T: -454 to 750°F (-270 to 400°C)

Type E: -454 to 1832°F (-270 to 1000°C)

Type N: -454 to 2372°F (-270 to 1300°C)

Type C: 32 to 4200°F (0 to 2315°C)

Type D: 32 to 4200°F (0 to 2315°C)

Type F: 32 to 2449°F (0 to 1343°C)

Type R: -58 to 3214°F (-50 to 1767°C)

Type S: -58 to 3214°F (-50 to 1767°C)

Type B: 32 to 3300°F (0 to 1816°C)

RTD (DIN): -328 to 1472°F (-200 to 800°C)

Process: -1999 to 9999 units

Advanced PID control algorithm

• Offers TRU-TUNE®+ adaptive control to provide tighter

control for demanding applications

• Enables auto-tune for fast, efficient start-up

Communication capabilities

• Provides a range of protocol options including

universal serial bus (USB) device port, Modbus® RTU,

EtherNet/IP™, Modbus® TCP, DeviceNet™ and

PROFIBUS

USB port

• Provides data log retrieval

SPLIT-RAIL control

• Allows modules mounted in separate high-voltage

and low-voltage cabinets to function as an integrated

system

• Minimizes the length and cost of wire runs and

improves system reliability by locating inputs closer to

sensors and outputs closer to loads

AUTO CLONE

• Reduces time and configuration complexity by

automatically building a new module with the same

parameter settings as the replaced module

SENSOR GUARD

• Prevents unplanned process shutdowns and product

loss by switching to a backup sensor if the primary

sensor fails

Benefits of using an integrated controller solution:

• Reduces wiring time and termination complexity

compared with connecting multiple discrete products

• Improves system reliability

• Reduces termination and installation cost

• Eliminates compatibility issues often encountered with

using various discrete components and brands

• Reduces troubleshooting time and downtime costs

because the system can specifically identify any

problems with a sensor, controller, solid state relay

(SSR) power output or heater load

• Complete thermal solution saves engineering

time and labor costs while shortening project

schedules

Features and Benefits

Multiple inputs; from one to 152 PID loops of

control or monitor up to 256 analog inputs

• Mix and match I/O to fit any application; from one

input with two outputs to 152 analog inputs with

152 outputs, or monitor up to as many as 256 analog

inputs all in one system

• Reduces cost because only required loops are

purchased

• Allows a common controller platform across many

design applications as both loops and outputs can

be ordered in single increments