Watlow F4T Process Controller

The F4T High End Watlow Process Controller from Anderson-Bolds

BUY the Watlow F4T HERE!

Watlow F4T Process Contoller

The Watlow F4T with INTUITION temperature & process controller offers a wide range of field removable I/O modules for maximum design flexibility. Configurations can be custom tailored to meet the scaling needs of a tremendous range of equipment and applications while providing exactly the hardware types required for compatibility. The F4T controller also features a 4.3 inch, color, graphical touch panel. Combining power, flexibility and functionality, this new controller offers unmatched versatility, and its best-in-class ease of use could very well make user manuals a thing of the past.
The F4T's batch processing feature can help with regulatory compliance, achieving data integrity in the plant, reducing warranty exposure, and even avoiding a potential recall scenario without significantly raising production costs. Download the specification sheet below to learn more.

Features and Benefits

4.3-inch, color touch panel with high-resolution, graphical

user-interface

• Shortens learning curve and reduces operator errors

• Allows channels, profiles, alarms, inputs and outputs to be

personalized with user defined names

Temperature PID, data logger, trend chart,

over/under-temperature limit, power switching,

math, logic, timers and counters combined into an

integrated system

• Lowers ownership costs

• Eliminates the need for separate discrete components

• Reduces complexity

• Simplifies design, ordering and installation

• Saves money

Robust algorithms for temperature, cascade, altitude,

humidity and compressor

• Improves process control

• Offers one to four channels of control

• Provides multiple PID sets

• Enables TRU-TUNE(R)+ adaptive control algorithm

• Offers 40 ramp and soak profiles with real-time clock and

battery backup

COMPOSER® graphical configuration PC software

• Speeds up and simplifies commissioning

• Archives and documents controller setup

• Connects with controller easily via Ethernet

Batch processing with bar code data entry

• Easily collects and manages data records

• Inputs information from bar code scan for fast and easy

data entry

• Offers foolproof processing via smart profile to part linkage

• Provides data security through password and data log

encrypted file options

• Improves manufacturing robustness via reminder screens

ensuring all data is entered during processing

• Helps ensure compliance with growing regulations and

minimizes warranty exposure

• Eliminates part processing skips or walk arounds due to

improved quality control

• Produces formatted data record report for easy receipt or

record management uses

Many communications options available including Ethernet

Modbus® TCP and SCPI and EIA-232/485 Modbus® RTU

• Offers two USB host ports and one device port

• Simplifies file transfers

• Connects easily

Modular design

• Adapts quickly to evolving requirements

• Offers numerous types of field pluggable modules for

maximum flexibility and easiest compatibility

• Features scalable and modular firmware functions

• Delivers scalable input/output quantities from 1 to 36

Agency certifications include UL®, FM, CE, RoHS, W.E.E.E.,

NEMA 4X/IP65

• Ensures high quality and reliability

• Verifies performance in installations worldwide

SERIES F4S/F4D/F4P backward compatible

• Provides easy retrofit with minimum pain and disruption

• Ensures proper fit in existing SERIES F4 panel cutout

Off-the-shelf solution

• Provides cost-effective “make versus buy”

• Offers preconfigured touch-panel screens

• Assures quicker time to market

Common Specifications

Line Voltage/Power

• Data retention upon power failure via nonvolatile memory

Functional Operating Range

• Type J: -346 to 2192ÅãF (-210 to 1200ÅãC)

• Type K: -454 to 2500ÅãF (-270 to 1371ÅãC)

• Type T: -454 to 750ÅãF (-270 to 400ÅãC)

• Type E: -454 to 1832ÅãF (-270 to 1000ÅãC)

• Type N: -454 to 2372ÅãF (-270 to 1300ÅãC)

• Type C: 32 to 4200ÅãF (0 to 2315ÅãC)

• Type D: 32 to 4200ÅãF (0 to 2315ÅãC)

• Type F: 32 to 2449ÅãF (0 to 1343ÅãC)

• Type R: -58 to 3214ÅãF (-50 to 1767ÅãC)

• Type S: -58 to 3214ÅãF (-50 to 1767ÅãC)

• Type B: 32 to 3300ÅãF (0 to 1816ÅãC)

• RTD (DIN): -328 to 1472ÅãF (-200 to 800ÅãC)

• Process: -1999 to 9999 units

Calibration Accuracy

• Calibration accuracy and sensor conformity: Å}0.1% of

span, Å}1ÅãC at the calibrated ambient temperature and

rated line voltage

• Types R, S, B: Å}0.2%

• Type T below -50ÅãC: Å}0.2%

• Calibration ambient temperature at 77ÅãF Å}5ÅãF (25ÅãC Å}3ÅãC)

• Accuracy span: 1000ÅãF (540ÅãC) min.

• Temperature stability: Typical Å}0.1ÅãF/ÅãF (Å}0.1ÅãC/ÅãC) rise in

ambient max.

Configuration Diagnostics

• Indicates if modules present match the expected

configuration settings

USB Host Port

• Total of 2 available

• Version: USB 2.0 hi-speed

• Connector: USB Type A, high-retention

• Flash drive must be FAT32 file system

• Max. current 0.5A/port

System Configuration Requirements

• F4T has 6 slots for flex modules (FM)

• EIA-232/485 Modbus(R) RTU flex module, if used, must occupy

slot 6 location

• A maximum of two 10A SSR FM modules can be used in the F4T

and each will require space for 2 slots. Valid in slots 1, 2, 4 or 5

Wiring Termination—Touch-Safe Terminals

• Right-angle and front-screw terminal blocks for input, output

and power supply connections

• Input, output and power terminals: touch safe, removable,

12 to 30 AWG

F4T Base Specifications

Line Voltage/Power

• High voltage option: 100 to 240VAC +10/-15%, 50/60Hz Å}5%

• Low voltage option: 24 to 28VAC/VDC+10/-15%, 50/60Hz Å}5%

• Power consumption: 23 W, 54VA

Environment

• NEMA 4X/IP65 front panel mount configuration only

• Operating temperature: 0 to 122ÅãF (-18 to 50ÅãC)

• Storage temperature: -40 to 185ÅãF (-40 to 85ÅãC)

• Relative humidity: 0 to 90%, non-condensing

Agency Approvals

• UL(R)/EN 61010 Listed, File E185611 QUYX

• UL(R) 508 Reviewed

• CSA CC.C#14, File 158031

• FM Class 3545 (configurations with limit modules)

• AMS 2750 E compliant: Analog input process values. Tip: Maximize

field calibration accuracy and uniformity by using advanced F4T

features such as Calibration Offset and Linearization Function

Blocks. Refer to user manual for details.

• RoHS by design, China RoHS Level 2, W.E.E.E.

• CE

• Windows(R) Hardware Certification

User Interface

• 4.3 inch TFT PCAP color graphic touch screen

• LED backlife >50K hours

• 4 keys: Home, Main Menu, Back, Help

• Multiple languages

• English, German, French, Italian, Spanish, Japanese, Korean

and Chinese

• USB wired or wireless mouse functionality

• Right click for 4 keys: Home, Main Menu, Back, Help

Control Loops

• 1 to 4 PID or ON-OFF control loops

• 0 to 6 Limit loops

• User-selectable action: heat, cool or heat/cool

• Auto-tune with TRU-TUNE+ adaptive control

Control Loops and Over-temperature Limits

• Input sampling: 10Hz

• Output update: 10Hz

Communications

• Ethernet Modbus(R) TCP

• Isolated communications

Profile Ramp and Soak Option

• Profile engine affects 1 to 4 loops in sync

• 40 profiles with 50 steps per profile

Data Logging

• User selectable parameters: Up to a maximum of 128 active

parameters depending on configuration

• Logging interval: Programmable increments between 0.1 seconds

and 60 minutes if logging to internal memory. Logging directly to

USB; 1.0 seconds to 60 minutes

• File types: .CSV for standard data logging or proprietary format for

encrypted data log option

• Storage: 80MB internal memory or to USB memory stick

• File transfer: Internal memory to USB host port or to Ethernet

Modbus(R) TCP

• Transfer options: On demand by user or user programmable based

on when a new data log file record is available. Utilizes TFTP and

Samba protocols

• Record: Date and time stamped

For a Watlow Quote on the F4T or other Watlow Products, click HERE!

Anderson-Bolds
216-360-9800
www.anderson-bolds.com

Watlow Process Controller F4T with Ramp Soak, Batches, 1-4 loops and communications.

Watlow Limit and Scanner Controllers

Anderson-Bolds Provides High Quality Watlow Temperature Control Products

Watlow LIMITS AND SCANNERS

Watlow single and multi-loop limits provide cost-effective solutions for single- and multi-channel, temperature monitoring. Limits monitor the process value where thermal system protection is needed, closing a contact output for normal operation and opening that contact to shut down the process or equipment when the value is outside the safe range.

Various configurations offer user-selectable or fixed-configuration sensor options including thermocouple, process, RTD and thermal switch inputs as well as user-settable or fixed limit values. Models with displays have user-selectable temperature units. Other features include sensor break protection, industry standard I/O options and UL® and CSA approval. All limits and scanners are RoHS compliant. Limits have FM approval for performance in limit (Over Temperature) applications. Watlow limits are designed and manufactured to withstand harsh industrial environments and come with a three-year warranty.

EZ-ZONE® PM LIMIT CONTROLLER

The EZ-ZONE PM panel mount limit controllers from Watlow® offer control options to reduce system complexity and the cost of thermal loop ownership. The EZ-ZONE PM limit controller provides high amperage power controller output and over/under limit control in one space saving, panel mount package.

Because EZ-ZONE PM limit controllers are scalable, the customer only pays for what is needed. This controller is available in 1/32, 1/16, 1/8 and 1/4 DIN panel mount packages.

RM LIMIT MODULE

The EZ-ZONE®RM high-density limit module used in conjunction with the EZ-ZONE RM temperature control module and high-density control module offer agency approved over and under temperature limit function to ensure system safety. The EZ-ZONE RM high-density limit controls 4, 8, or 12 limit loops per module or up to 192 limit loops per system.

SERIES LF TEMPERATURE LIMIT

Watlow's family of micro processor-based temperature limit controllers provide an economical solution for applications requiring temperature limit control. Temperature limit controllers are available in a broad range of packaging options, allowing selection of the best version for an individual application. Temperature limit 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 controllers 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 temperature limit controllers are factory mutual (FM) approved with special UL® approval for the open board potted versions. Watlow's temperature limit controllers include industry leading service and support and are protected by a three-year warranty.

SERIES LV TEMPERATURE LIMIT CONTROLLER

Watlow's microprocessor-based temperature limit controller 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. The temperature limit controller Series LV is available with an operator interface and can be ordered in 1⁄8 DIN-square panel mount or DIN-rail mount design configurations.

The variable SERIES LV temperature limit controller 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 temperature 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® PM EXPRESS LIMIT CONTROLLER

The EZ-ZONE PM Express panel mount limit controller from Watlow’s family of limit controls is an industry leading limit controller that allows for optimal performance utilizing simple over/under limit control and menu functionality without complex features. The EZ-ZONE PM Express limit controller is ideally suited for basic applications and usage levels.

The EZ-ZONE PM Express limit controller is the next generation of controllers leveraging the strong legacy of Watlow's SERIES 94, SERIES 945 and SERIES SD limit controllers where easy-to-use features are needed for basic applications. It includes one universal input and the option for up to two outputs and is available in 1⁄32 and 1⁄16 DIN panel mount limit controls packages.

The EZ-ZONE PM Express limit controls are a great addition to the EZ-ZONE PM family which includes two other controller versions, the EZ-ZONE PM integrated controller and the EZ-ZONE PM temperature and process controller. This family provides an ideal platform to perform many applications.

RM SCANNER MODULE

The EZ-ZONE® RM high-density scanner module can be used in conjunction with any EZ-ZONE RM family module as a monitor or to provide additional logic function to a system. The scanner module can also be used as a stand alone product for multiple inputs of monitoring applications. The EZ-ZONE RM high-density scanner module provides 4, 8, 12 or 16 loops of monitoring per module or up to 256 monitoring loops per system.

Anderson-Bolds
216-360-9800
Contact Anderson-Bolds

Watlow 1/4 DIN Temperature Controllers

Watlow Process 1/4 DIN Controllers from Anderson-Bolds

The Watlow SERIES F4 1⁄4 DIN temperature process controller offers performance features to meet a wide range of industrial processing needs. The F4 process controller is ideal for semiconductor manufacturing equipment, plastic processing and packaging equipment and industrial process control applications.

The F4 Watlow process controller features a four line, high definition LCD interface display, in addition to an information key that enables easy set up and control operation, minimizing the chance for error. Its 16-bit microprocessor ensures accuracy and delivers performance advantages you can count on from a Watlow controller.

Four digital inputs remotely modify the F4’s operation or enable display of pre-defined operator messages. Advanced process controller features include cascade, ratio, differential, duplex slide wire and retransmit options.

Serial communication and dual alarm relays are included in the base unit. The WATLOW SERIES F4 is packaged with a
NEMA 4X front face to withstand harsh environments anda four-inch (101.6 mm) deep case with removable connectors for wiring convenience. It is manufactured by Watlow, ISO 9001 registered and protected by a three-year warranty.

Use our Watlow Parts form to get a quote.

Watlow F4 Process Controller

Features and Benefits

Guided setup

• Removes “guess work” from the setup process 
• Saves time by reducing programming errors 
• High definition four-line LCD display 

• Simplifies setup process and operations 
• Quickly and easily identifies process, alarm and
  set point values 
• Information “I” Key 

• Displays essential elements from the user manual on board

Customized menuing

• Quickly displays up to 16 parameters 
• Allows users to create custom messaging and easily
  identify key events or alarms 
• High performance 16-bit microprocessor 

• Provides precise process control with 20Hz update rate on input 1. (10Hz on inputs 2 and 3) 
• Calibration accuracy of ±0.1 percent of span 
• Universal input 
• • Embedded software provides application versatility 
• • Eliminates the need for dip switches 
• Modbus® communications ready 

• Equipped to handle RS232 or EIA485 communications

Example Watlow F4P Temperature Controller Part numbers:

F4PH-EEA-01RG - Watlow Process Temperature Controller

Controller with 2 relay outputs and standard control operation.

F4PH-EEB-01RG - Watlow Process Temperature Controller

Controller with 2 relay outputs and enhanced control operation (dual universal inputs, cascade, ratio, duplex, differential, slide wire)

F4PH-FEA-11RG - Watlow Process Temperature Controller

Controller with analog output and a relay output and standard control operation and retransmit analog signal.

F4PH-FEB-11RG - Watlow Process Temperature Controller

Controller with analog output and a relay output and enhanced control operation (dual universal inputs, cascade, ratio, duplex, differential, slide wire) and retransmit analog signal.

The Watlow EZ-ZONE®PM panel mount 1/4 DIN controller offers control options that reduce system complexity and thermal loop ownership cost. It can be ordered as a PID controller, an over/under limit controller or its functions can be combined into an integrated controller. An option to integrate a high amperage power controller output with a high-performance PID controller and an over/under limit controller in one space-saving, panel mount package is also available. Many communications options are offered to support connectivity needs.

Because the Watlow EZ-ZONE PM panel mount controller is highly scalable, you pay only for what is needed. This controller is available in 1⁄32,1⁄16,1⁄8 and1⁄4 DIN panel mount packages. The Watlow EZ-ZONE PM controller is easy to use and is ideal for PID controller, over/under limit controller or integrated controller needs.

Watlow PM EZ-Zone Controllers

Features and Benefits

Integrated PID and limit controller

• Reduces wiring time and termination complexity

compared with connecting discrete products

• Decreases required panel space

• Lowers installation costs

• Increases user and equipment safety for over/under

temperature conditions

High amperage power control output

• Drives 15 ampere resistive loads directly

• Reduces component count

• Decreases cost of ownership

Current monitoring

• Detects heater current flow and provides alarm indication

of a failed output device or heater load

• Drives output on open or shorted heater

Serial communication capabilities

• Provides a wide range of protocol choices including

Modbus(R) RTU, EtherNet/IP™, Modbus(R) TCP, PROFIBUS

DP and DeviceNet™

• Supports network connectivity to a PC or PLC

Dual-channel controller

• Provides two PID controllers in one space-saving package

Enhanced control options

• Easily handles complex process problems such as

cascade, ratio, differential, square-root, motorized valve

control without slidewire feedback, wet-bulb/dry-bulb,

compressor control and peltier loads

Countdown timer option

• Provides batch process control

• Supports set point change during countdown

Advanced PID control algorithm

• Offers TRU-TUNE(R)+ adaptive control to provide tighter

control for demanding applications

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

Configuration communications with software

• Includes Watlow standard bus communications and

EZ-ZONE configurator software

• Saves time and improves reliability of controller setup

Ten-point linearization curve

• Improves sensor accuracy

Built-in sensor compensation curves

• Saves cost of buying compensated sensors

• Includes Vaisala RH and altitude (pressure) curves

Remote set point operation

• Supports convenient set point manipulation from a

remote device such as a master control or PLC

Profile capability

• Offers pre-programmed process control

• Allows ramp/soak programming with 40 total steps,

battery backup and real time clock

Retransmit Output

• Supports industry needs for recording

Factory Mutual (FM) approved over/under limit with

auxiliary outputs

• Increases user and equipment safety for over/under

temperature conditions

Memory for saving and restoring parameter settings

• Decreases service calls and time down

Agency approvals: UL® listed, CSA, CE, RoHS, W.E.E.E.,

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

models

• Assures prompt product acceptance

• Reduces end product documentation costs

Touch-safe package

• Increases safety for installer/operator

• Complies with IP2X requirements

Consistent termination labeling connection system

• Simplifies switching between products

• Speeds up user’s system documentation

EZ-KEY

• Enables simple, one-touch operation of user-defined,

repetitive activities

Programmable menu system

• Reduces setup time and increases operator efficiency

Three-year warranty

• Provides product support and reliability

Watlow EZ-ZONE PM PM4C1EA-AAAAAAA Integrated PID Digital Display Temperature Control, 1/4 DIN, PID Control, Two 4 digit digital displays, Universal input, 100-240 VAC

Output 1: 5 amp Form C Mechanical Relay

Watlow EZ-ZONE PM PM4C1EJ-AAAAAAA Integrated PID Digital Display Temperature Control, 1/4 DIN, PID Control, Two 4 digit digital displays, Universal input, 100-240 VAC

Output 1: 5 amp Form C Mechanical Relay 

Output 2: 5 amp Form A Mechanical Relay

Watlow EZ-ZONE PM PM4R1EJ-AAAAAAA PID Digital Display Temperature Control, 1/4 DIN, PID Control with RAMP SOAK capability, Two 4 digit digital displays, Universal Sensor input, 100-240 VAC

Output 1: 5 amp Form C Mechanical Relay 

Output 2: 5 amp Form A Mechanical Relay

Watlow EZ-ZONE PM PM4C1EJ-AAEAAAA Integrated PID Digital Display Process/Temperature Control, 1/4 DIN, PID Control, Two 4 digit digital displays, Universal input, 100-240 VAC

Output 1: 5 amp Form C Mechanical Relay 

Output 2: 5 amp Form A Mechanical Relay

Output 3: 5 amp Form C Mechanical Relay

Watlow EZ-ZONE PM PM4C1EJ-AAEKAAA Integrated PID Digital Display Temperature Control, 1/4 DIN, PID Control, Two 4 digit digital displays, Universal Sensor input, 100-240 VAC

Output 1: 5 amp Form C Mechanical Relay 

Output 2: 5 amp Form C Mechanical Relay

Output 3: 5 amp Form C Mechanical Relay

Output 4: SSR Form A, 0.5A

Watlow EZ-ZONE PM PM4C4KH-ALEJAAA Integrated PID Digital Temperature Control, 1/4 DIN, PID Control, Two 4 digit digital displays, Universal input, 20-28 VAC and 12-40 VDC

Output 1: SSR Form A, 0.5A

Output 2: NO-ARC 15 A power control

Output 3: 5 amp Form C Mechanical Relay

Output 4: 5 amp Form A Mechanical Relay

Watlow EZ-ZONE PM PM4C1KK-ALEJAAA Integrated PID Digital Display Temperature Control, 1/4 DIN, PID Control, Two 4 digit digital displays, Universal input, 100-240 VAC

Output 1: SSR Form A, 0.5A

Output 2: SSR Form A, 0.5A

Output 3: 5 amp Form C Mechanical Relay

Output 4: 5 amp Form A Mechanical Relay

Watlow EZ-ZONE PM PM4C4FJ-6AAAAAA Integrated PID Digital Temperature Control, 1/4 DIN, PID Control, Two 4 digit displays, Universal input, 20-28 VAC and 12-40 VDC

Output 1: Universal Process - 4-20mA, 0-10vdc, 0-20mA

Output 2: None

Output 3: None

Output 4: None

Communications: PROFIBUS DP

Watlow EZ-ZONE PM PM4C4FJ-3AAAAAA Integrated PID Digital Display Temperature/Process Control, 1/4 DIN, PID Control, Two 4 digit digital displays, Universal input, 20-28 VAC and 12-40 VDC

Output 1: Universal Process - 0-10vdc, 0-20mA, 4-20mA

Output 2: 5 amp Form A Mechanical Relay

Output 3: None

Output 4: None

Communications: EtherNet/IP/Modbus TCP

For questions/quotes/comments email to wallow@anderson-bolds.com

216-360-9800 / 614-885-3933

Process Temperature Controls

Process Temperature Control from Anderson-Bolds

Temperature and process controllers are used over a vast range of industrial, scientific and commercial applications. These controllers automatically adjust outputs based on sensor feedback working in concert to control process variables such as temperature, flow, pressure and relative humidity, as well as, to achieve an optimized and stable process.

Temperature Control in manufacturing is a quintessential part of proper product formation. If the temperature slips above or below the ideal range needed for a particular stage in a manufacturing process, the results can be harmful—improperly adhered coatings, a weakened base material, or an overall compromised component—so it becomes increasingly important that the manufacturer not only determine the proper temperature for each stage, but also monitor the temperature inside the machine and receive appropriate feedback. 

Temperature controllers in manufacturing operations serve exactly this function: they ensure that a machine is running properly by gauging the temperature at different stages in the process and comparing the data to the programmed temperature specifications. As a result, manufacturers can quickly and easily discover temperature related machine malfunctions, and treat them as necessary. 

A temperature controller is a device used to hold a desired temperature at a specified value.

In a typical application, sensors measure the actual temperature. This sensed temperature is constantly compared to a user set point. When the actual temperature deviates from the set point, the controller generates an output signal to activate other temperature regulating devices such as heating elements or refrigeration components to bring the temperature back to the set point.

Temperature controllers have inputs. The inputs are used to measure a variable in the process being controlled. In the case of a temperature controller, the measured variable is temperature.

In addition to inputs, a temperature controller also has an output. Each output can be used to do several things including control a process (such as turning on a heating or cooling source), initiate an alarm, safe guard a process with a HI or LOW Limit shutdown or to retransmit the process value to a programmable logic controller (PLC) or recorder.

Limit controllers provide safety limit control over process temperature. They have no ability to control temperature on their own. Put simply, limit controllers are independent safety devices to be used alongside an existing control loop. They are capable of accepting thermocouple, RTD, or process inputs with limits set for high or low temperature just like a regular controller. Limit control is latching and part of redundant control circuitry to positively shut a thermal system down in case of an over-limit condition. The latching limit output must be reset by an operator; it will not reset by itself once the limit condition does not exist. A typical example would be a safety shut off for a furnace. If the furnace exceeds some set temperature, the limit device would shut the system down. This is to prevent damage to the furnace and possibly any product that may be damaged by excessive temperatures. Or to Prevent dangerous situations like explosions or fires.

On/Off Temperature Controls

An on/off temperature control is the least expensive of the control types, and also the most simple in terms of how it works. The control is either on or off—if the temperature drops below a certain point, the control signals to the machine to turn raise the temperature. Likewise, if a temperature goes above a certain point, the control is triggered to tell the machine to lower the temperature. A common example of on/off systems is a household thermostat. When the temperature drops below a certain point, the controller triggers the heater to raise the temperature back to the programmed value. With air-conditioning it works the other way: if the temperature rises past a certain point, the controller triggers the air-conditioner, dropping the temperature back to the programmed norm.

On/off controls are often used in processes where the temperature change is very slow, and precise control of temperature isn’t necessary.

Proportional Control

Unlike on/off controls, which only respond when a set limit is reached, proportional controls are designed to respond to temperature change before it slips out of the desired range. Essentially, proportional controls increase or decrease the power supply as the temperature reaches its upper or lower limit, or setpoint, which slows or speeds the heater and helps stabilize the temperature. 

The temperature range in which proportional controls either lessen or increase the power supply to slow or speed heating is known as the “proportional band.” If a temperature reaches the lower or upper setpoints, the control then functions as a full on/off control—the temperature is either turned fully on to increase the temperature, or fully off to drop the temperature. When the temperature is within the proportional band, and the power supply is decreased or increased, the heat is raised or lowered in relation to how far the temperature is from the set point. 

There are many types of temperature loops that are in everyday life. The most common would be the home temperature loop to keep a home warm or cool.  The Thermostat measures temperature and then decides to turn on the heating or cooling to satisfy the SET temperature.  When the setting is matched the system will turn off until there is a mis-match again. 
Another temperature loop involves taking a shower.  The person taking he shower becomes the sensor and adjusts the temperature of the water based on its hotness or coldness against the skin and mixing the hot and cold water from the spigot. Other temperature loops are hot water tanks, tankless water heaters, ovens and cars/trucks (engine cooling and cabin temperature regulation (AC or heat).

In industry, more sophisticated means are needed as more precise temperature control is needs.  Thus the rise of the Process Temperature controller.  Using PID control and very small time intervals, Process controllers can control to tenths of degrees by switching electric heaters on or off in microseconds or by adjusting voltages to control wattage output (like a dimmer switch.)  

We can help size a thermal system with the right heater, sensor type and placement and temperature controller.  Contact Anderson-Bolds for expert help with process heating applications.  We can definitely enhance your process.

216-360-9800
info@anderson-bolds.com