Watlow Mercury Relay or MDR Retrofit User Manual

Using This Retrofit Guide

This document is best viewed with Adobe Reader 6.0. To obtain the latest version of Adobe Reader, visit

http://www.adobe.com

Specification sheets on Watlow product may be obtained at http://www.watlow.com/literature/specsheets/
User Manuals on Watlow product may be obtained at http://www.watlow.com/literature/prodtechinfo/
Additional information on other Watlow products may be obtained by visiting http://www.watlow.com/

To locate a controller, search on the part number such as 965A-1CD0-00RG. Use the Help feature in Adobe Reader on
how to search documents.

If there are multiple listings, then the retrofit is conditional upon field use. Select the appropriate selection. The User’s
Manual is included at the bottom of this document when availab le.

Before selecting a replacement controller:

1. Know the application.

• Temperature range

• Sensor type

• Is the sensor upgradable if required?

• Additional input requirements – remote set points, secondary sensor or events

• Output required – control, alarm, event

• Is the power-switching device upgradable?

• Operating voltage of controller

• Mounting requirements – panel space

• Is a safety limit device required?

2. Know the product.

• Inputs – type and number of

• Control function – direct (cool) or reverse (heat )

• Outputs – switched DC, SSR, or mechanical relay

• Communication requirements

• Which control features are required? (cascade, slidewire, differential, remote control, other)

3. Use your best judgment for selecting a replacement controller. All applications require close examination of input,

output and the control mode needs to have the controller function properly.

4. Safety: Remember to make sure all redundant safety equipment is in place and working when retrofitting equipment.

If a system has been retrofitted without the proper safety equipment, you could be liable if an accident occurs.

This is only a guide to replacement controllers. If you have doubts, please call [phone]
and ask for technical support or email [e-mail]. We’re here to help. The
suggested replacement will differ in fit and form. Please review the replacement controller
specifications for suitability. Carefully check the notes for additional information that may
apply.

Your comments or suggestions on the Retrofit Guide are welcome. Please send comments or corrections to: Technical
Writer, Watlow Controls, 1241 Bundy Boulevard, P.O. Box 5580, Winona, MN 55987-5580; phone [phone]; fax
[phone].

This Retrofit Guide is copyrighted by Watlow Winona, Inc., © February 2004 with all rights reserved. (1455)

Abbreviation & Terminology

(as used in this document)

0.5 – 0.5 amperes of current switching capability

2A – 2 amperes of current switching capability

5A - 5 amperes of current switching capability

10A – 10 amperes of current switching capability

15A – 15 amperes of current switching capability

12-24 – Supply voltage can be between 12 to 24 Volts

100-240 – Supply voltage can be between 100 to 240 Volts

100 ohm DIN – refers to 100-ohm platinum RTD that has a DIN curve.

100 ohm JIS – refers to 100-ohm platinum RTD that has a JIS curve.

1/32 DIN – Deutsche Industrial Norm standard for panel mounted controller, hole size is cut to 1.78”w x 0.88”h.

1/16 DIN – Deutsche Industrial Norm standard for panel mounted controller, hole size is cut to 1.78”w x 1.77”h.

1/8V DIN – Deutsche Industrial Norm standard for panel mounted controller, hole size is cut to 1.78”w x 3.63”h.

1/8H DIN – Deutsche Industrial Norm standard for panel mounted controller, hole size is cut to 3.63”w x 1.77”h”

1/8S DIN – Deutsche Industrial Norm standard for panel mounted controller, hole size is cut to 2.68”w x 2.68”h.

¼ DIN – Deutsche Industrial Norm standard for panel mounted controller, hole size is cut to 3.63”w x 3.63”h.

Action – determines the direction of control. Heat (reverse acting) or Cool (direct acting).

Auto Reset – the limit will automatically reset on a power cycle but requires manual reset on limit trip.

Cascade – a control algorithm in which the output of one control loop provides a set point for another loop. The second

loop, in turn, determines the control action.

Ch – Channel refers to an analog input. There are single and dual channel controllers.

Control Mode – the method that a controller uses to switch the outputs such as PID, ON/OFF, and Manual.

Differential - control algorithm in which the output is based on the difference of the inputs plus set point.

DIN – Deutsche Industrial Norm, a set of technical, scientific and dimensional standards developed in Germany. RTD

sensors with the DIN curve change resistance at a rate of 0.00385 ohms/ohms/C.

DIN Rail – standard DIN EN50022 mounting method for attaching devices onto a metal rail.

Fixed – refers to a set point that is fixed at one value.

High Limit - device will deactivate output on a temperature rise above set point.

Inductive Load – any device that has a wire winding such as solenoids, electromechanical relays or transformers.

Input – refers to the sensor types that may be connected.

Integral – the set point in integral (on board) to the controller.

JIS – Joint Industrial Standards, a set of technical, scientific and dimensional standards developed in Japan. RTD sensors

with the JIS curve change resistance at a rate of 0.00396 ohms/ohms/C.

Line Voltage – the voltage required powering the electronics of the controller.

Low Limit - device will deactivate output on a temperature drop below set point.

On/Off – a method of control that turns the output full on until set point is reached and then off until the process error

exceeds the hysteresis.

Open Brd – the form factor of this controller is an open circuit board mounted on four standoffs.

Manual Reset – the limit must be reset on a power cycle and requires manual reset on limit trip.

Multi RSP – multiple remote set potentiometers were supported. Each allowed the set point to be selected and adjusted.

Relay – refers to an electromechanical relay.

Remote – set point is adjusted using a remote potentiometer.

Panel – the form factor of this controller is mounted through a hole cut in the panel.

PI – Proportional and Integral, a control mode with two functions: proportional action dampens the systems response,

and integral corrects for droop.

PID – Proportional, Integral, and Derivative, a control mode with three functions: proportional action dampens the

systems response, integral corrects for droop, and derivative prevents overshoot and undershoot.

Potted – the circuit board and electronics are encased in epoxy.

Proc – Process input may accept 0-5, 1-5, 0-10 volts or 0-20 and 4-20 mA.

Profiling – Controller will perform a sequence of programmed steps.

Programmable – The feature is changeable in the field through jumpers and/or parameter selection.

RTD – Resistance Temperature Detector, a sensor that is 100 ohms at 0 degrees C and made of platinum material.

SSR – Solid State Relay, these devices will switch AC voltage only and require a load to latch on.

Sw DC – Switched DC, a time proportioning DC output used to drive DC input solid state relays.

t/c – Thermocouple sensor device made by joining two dissimilar metals whose standards is identified by a letter.

Temp Range – the range over which the controller could have the set point adjustment.

Thermistor – a sensor that changes resistance as the temperature changes. Similar but not the same as an RTD.

Universal – Input can be a thermocouple, 100 ohm DIN RTD or process (volts or milliamperes)

VAC – Volts Alternating Current

VAC/DC- Volts Alternating Current or Direct Current

VDC – Volts Direct Current

VTB Sw DC – Variable Time Base Switched Direct Current, a time proportioning DC output where the cycle time is

variable.