Watlow 998 User Manual [en, de, es, fr]

Series 998

Dual Channel, 1/8 DIN, Microprocessor-Based

Temperature/Process Controller

0600-0010-000 Rev G

February 2000
Supersedes: W998-XUMN Rev F

$10.00

Made in the U.S.A.

Printed on Recycled Paper 10% Postconsumer Waste

User’s Manual

Watlow Controls

1241 Bundy Boulevard, P.O. Box 5580, Winona, Minnesota USA55987-5580

Phone: [phone], Fax: [phone] http://www.watlow.com

User Levels:

• New User........................... go to Introduction

• Experienced User................... go to page 4.1

• Expert User............................. go to page 4.1

Installers:

• Set-up..................................... go to page 1.1

• Installation & Wiring ................go to page 2.1

CUS

CTI

TOTAL

CUS

TOMER

SATISFACTI

3 Year Warranty

ON

ISO 9001

Registered Company

Winona, Minnesota USA

Using the Manual

NOTE:
Details of a “Note”
appear here in the
narrow box on the
outside of each
page.

CAUTION:
Details of a
“Caution” appear
here in the narrow
box on the outside
of each page.

WARNING:
Details of a
“Warning”appear
here in the narrow
box on the outside
of each page.

Safety Information

We use note, caution and warning symbols throughout this book to draw
your attention to important operational and safety information.A bold text
“NOTE” marks a short message in the margin to alert you to an important
detail.

A bold text “CAUTION” safety alert appears with information that is
important for protecting your equipment and performance. Be especially
careful to read and follow all cautions that apply to your application.

A bold text “WARNING” safety alert appears with information that is
important for protecting you, others and equipment from damage. Pay
very close attention to all warnings that apply to your application.

The safety alert symbol, ç, (an exclamation point in a triangle) precedes
a general CAUTION or WARNING statement.

Technical Assistance

If you encounter a problem with your Watlow controller, review all of your
configuration information for each step of the setup to verify that your
selections are consistent with your applications.

If the problem persists, an Application Engineer can discuss your applica­tion with you.

Before calling, please have the complete model number and user’s manu­al available. You can get technical support by dialing 507/494-5656, 7
a.m. to 7 p.m. Central Standard Time.

Your Feedback

Your comments or suggestions on this manual are welcome, please send
them to: Technical Writer, Watlow Controls, P.O. Box 5580, Winona, MN
55987-5580, Phone: [phone], Fax: [phone]. The Series
998 User’s Manual is copyrighted by Watlow Winona, Inc., © February
2000, with all rights reserved. (1832)

Table of Contents

Introduction
Starting Out with the Watlow Series 998

i The Series 998
ii Display Loop
ii Operation Menus
iii Setup Menus
iii Factory Menus

Chapter 1
Hardware Setup

1.1 DIP Switch Locations and Functions

1.2 Input Type DIP Switches

1.3 External Power Supply DIP Switches

1.4 Setting the Lockout DIP Switch

Chapter 2
Installation and Wiring

2.1 Panel Cutout and Dimensions

2.2 Installing the Series 998

2.4 Wiring the Series 998

2.4 Power Wiring

2.4 Sensor Installation Guidelines

2.5 Event Input 1 Wiring

2.5 Wiring 0-20mA and 4-20mA
Process Inputs

2.6 Wiring Example

2.7 Wiring Notes

2.8 Channel A Input Wiring

2.9 Channel B Input Wiring

2.10 Channel A Output Wiring

2.11 Channel B Output Wiring

2.12 Output 3 Wiring

2.13 Output 4 Wiring

Chapter 5
The Operation Menus

5.1 Navigating the Operation Menus

5.2 The System Menu

5.3 The Set Point Menu

5.3 System Prompts

5.8 PID A Menu

5.13 PID B Menu

Chapter 6
The Factory Menus

6.1 Navigating the Factory Menus

6.2 Panel Lockout Menu

6.8 Diagnostics Menu

6.14 Calibration Menu

Chapter 7
Tuning, Manual Operation, Alarms and
Error Codes

7.1 Auto-tuning (Heat and/or Cool)

7.2 Manual Tuning

7.3 Manual and Automatic Operation

7.4 Changing the Output 3 Alarm Jumper

7.4 Using Alarms

7.6 Error Code E1 and E2 Messages

7.7 Error Code Actions

Chapter 8
Applications

8.1 Burst Fired, Zero Cross Output

8.2 Retransmit

8.3 Dead Band

8.3 Transmitter Power Supply

Chapter 3
Keys and Displays

3.1 Keys and Displays

3.2 Display Key and Loop

Chapter 4
The Setup Menus

4.1 Navigating the Setup Menus

4.2 Input Menu

4.16 Output Menu

4.32 Global Menu

Appendix

A.1 Warranty and Returns
A.2 Glossary
A.5 Index
A.7 Prompt Index
A.8 Specifications
A.9 Ordering Information
A.10 Declaration of Conformity

WATLOW Series 998 User’s ManualTable of Contents

Notes

Table of ContentsWATLOW Series 998 User’s Manual

WATLOW Series 998 User’s Manual i

Introduction

Starting Out With the Watlow Series 998

Figure i ­The Series 998.

TL

W

W

A

PROCESS

1A 2A 1B 2B

CH A
CH B

DISPLAY

SERIES 998

MODE

AUTO

MAN

Channel A Control Outputs
(Output 1A and 2A)

Channel B Control Outputs
(Output 1B and 2B)

Optional Outputs 3 and 4
(alarms, retransmit or
PC communications)

Channel A Input

(Input 1)

Channel B Input

(Input 2)

Event Input

Watlow’s Series 998 process controller is capable of two independent
channels of process control. Each channel can be configured and tuned
separately. Each alarm option (outputs 3 and 4) can be used to trigger an
alarm based on either channel. The retransmit option, available on output
3, can be used to retransmit the process or set point value of either chan­nel. The digital communications option can be used to configure and
monitor the controller with a personal computer from a remote location.

If you are unfamiliar with general controller operation, it’s a good idea to
read through the entire manual. The manual is organized in setup order,
with chapters on wiring, menus, operation and applications. If you under­stand the concept of process/temperature controls and feel comfortable
skipping around through the manual, use the black tabs at the top of
each page to quickly scan the pages and find the topic needed. The Menu
Overview on the next page is a great place to start. Also, refer to Chapter
3 for information on the keys and displays.

The menu map is an overview of all menus and prompts and how to navi­gate between them. There are three main menu sets: Setup menus

[`SEt]; Operation menus [OPEr]; and Factory menus [Fcty]. You can

return to the Display Loop from anywhere by pressing the Display key.
DIP switch locations and settings are explained later in Chapter 1.

Introduction

Introduction

Introduction

ii WATLOW Series 998 User’s Manual

From the Display Loop, press the Mode key µ to reach the Operation
menus.

To return to the Display Loop from any point in any menu, press the
Display key ∂.

From the Display Loop, press both the Up-arrow and Down-arrow keys

> and < for three seconds to reach the Setup menus. Hold them

down for another three seconds to reach the Factory menus.

Display Loop

Operation Menus

[`998]

[SP2A]

Set Point 2A

[`998]

[`SyS]

µ

[SP2b]

[OPEr]

[Ei1S]
[Ot3S]
[Ot4S]
[A3LO]
[A3HI]
[A4LO]
[A4HI]
[`AUt]

Set Point 2B

System Menu

Operation Menus
Event Input 1 Status
Output 3 Status

Output 4 Status
Alarm 3 Low
Alarm 3 High
Alarm 4 Low
Alarm 4 High
Auto-tune

µ

Channel A

Process

[`75]

[100]

Channel A

Set Point

[PiDA]

[Oper
[PB1A]
[rE1A]
[It1A]
[rA1A]
[dE1A]
[Ct1A]
[Pb2A]
[rE2A]
[It2A]
[rA2A]
[dE2A]
[Ct2A]
[db`A]

Channel B

Process

∂

[`80]

[125]

Channel B

Set Point

∂

>

PID A Menu

Operation Menus
Output 1 Proportional Band A

Output 1 Reset A
Output 1 Integral A
Output 1 Rate A
Output 1 Derivative A
Output 1 Cycle Time A
Output 2 Proportional Band A
Output 2 Reset A
Output 2 Integral A
Output 2 Rate A
Output 2 Derivative A
Output 2 Cycle Time A
Dead Band A

Channel A

Process

[`75]

[`80]

Channel B

Process

>>

∂

∂

µ

[```]

[`°F]

Process

Units

[PiDb]

[OPEr]

[Pb1b]
[rE1b]
[It1b]
[RA1b]
[dE1b]
[Ct1b]
[Pb2b]
[rE2b]
[It2b]
[rA2b]
[dE2b]
[Ct2b]
[db`b]

PID B Menu

Operation Menus
Output 1 Proportional Band B

Output 1 Reset B
Output 1 Integral B
Output 1 Rate B
Output 1 Derivative B
Output 1 Cycle Time B
Output 2 Proportional Band B
Output 2 Reset B
Output 2 Integral B
Output 2 Rate B
Output 2 Derivative B
Output 2 Cycle Time B
Dead Band B

Introduction

WATLOW Series 998 User’s Manual iii

Introduction

From the Setup menus, press both the Up-arrow and Down-arrow keys > and

< for three seconds to reach the Factory menus.

To return to the Display Loop from any point in any menu, press the Display key

∂.

Setup Menus

[InPt]

[`SEt]

µ µ

[`In1]
[dEC1]
[`rL1]
[`rH1]
[CAL1]
[rtd1]
[Ftr1]
[`In2]
[dEC2]
[`rL2]
[`rH2]
[CAL2]
[rtd2]
[Ftr2]
[Lin2]
[`Alt]

Input Menu

Setup Menus
Input 1

Decimal 1
Range Low 1
Range High 1
Calibration Offset 1
RTD Calibration Curve 1
Input 1 Software Filter
Input 2
Decimal 2
Range Low 2
Range High 2
Calibration Offset 2
RTD Calibration Curve 2
Input 2 Software Filter
Input 2 Linearization
Altitude

>

[OtPt]

[`SEt]

[Ot1A]
[HY1A]
[Ot2A]
[HY2A]
[PrcA]
[Ot1b]
[HY1b]
[Ot2b]
[HY2b]
[Prcb]
[`Ot3]
[`Al3]
[HYS3]
[LAt3]
[SIL3]
[`Ot4]
[`AL4]
[HYS4]
[LAt4]
[SIL4]
[Aout]
[Prc3]
[`ArL]
[`ArH]
[ACAL]

>

Output Menu

Setup Menus
Output 1A

Hysteresis 1A
Output 2A
Hysteresis 2A
Process A
Output 1B
Hysteresis 1B
Output 2B
Hysteresis 2B
Process B
Output 3
Alarm 3
Hysteresis 3
Latching 3
Silencing 3
Output 4
Alarm 4
Hysteresis 4
Latching 4
Silencing 4
Analog Output
Process 3
Retransmit Low Limit
Retransmit High Limit
Retransmit Calibration Offset

>

[gLbl]

[`Set]

µ µ

[`C_F]
[FAIL]
[`err]
[`Ei1]
[Anun]
[AtSP]
[rP`A]
[rt`A]
[rP`b]
[rt`b]

Global Menu

Setup Menus
Celsius-Fahrenheit

Failure Mode
Error Latching
Event Input 1
Annunciator
Auto-tune Set Point
Ramping Channel A
Ramp Rate Channel A
Ramping Channel B
Ramp Rate Channel B

>

[COM]

Communications Menu

[`SEt]

Setup Menus

[bAUd]

Baud Rate

[dAtA]

Data Bits and Parity

[Prot]

Protocol Type

[Addr]

Address

[IntF]

Interface Type

Factory Menus

[PLOC]

[Fcty]

µ

[`LOC]
[`SYS]
[PidA]
[Pidb]
[InPt]
[OtPt]
[gLbL]
[COM]
[diAg]
[`CAL]

Panel Lockout Menu

Factory Menus
User Lockout

System Menu Lockout
PID A Menu Lockout
PID B Menu Lockout
Input Menu Lockout
Output Menu Lockout
Global Menu Lockout
Communications Menu Lockout
Diagnostics Menu Lockout
Calibration Menu Lockout

>

[diAg]

[Fcty

µ µ

[dAtE]
[SOFt]
[Sn--]
[AMb]
[`gnd]
[`rEF]
[cnt1]
[cnt2]
[itY1]
[ity2]
[OtY1]
[OtY2]
[OtY3]
[OtY4]
[dISP]
[tout]

Diagnostics Menu

Factory Menus
Factory Ship Date

Software Revision
Serial Number
Ambient Temperature
Ground A/D Count
Ambient A/D Count
Input 1 A/D Count
Input 2 A/D Count
Input 1 Module
Input 2 Module
Output 1 Module
Output 2 Module
Output 3 Module
Output 4 Module
Test Displays
Test Outputs

>

[`CAL]

>

[Fcty]

[A`50]
[A`00]
[``tc]
[a`OH]
[A`20]
[A`15]
[A380]
[A10U]
[A`OU]
[A20A]
[A`4A]
[A`Ou]
[A100]
[b`50]
[b`00]
[b`OH]
[b`20]
[b`15]

Calibration Menu
Factory Menus

[b380]
[b10U]

µ

[b`OU]
[b`4A]
[b`Ou]
[b100]
[1`4`]
[1`20]
[1`10]
[110`]
[2`4`]
[2`20]
[2`0`]
[2`10]
[3`LO]
[3`HI]
[`rSt]
[`dFL]

Restore Factory Values
Default Prompts

iv WATLOW Series 998 User’s Manual

Notes

Introduction

Chapter 1 Hardware Setup

DIP Switch Locations and Functions

The Watlow Series 998 has at least one and as many as six dual in-line
package (DIP) switches inside the controller, depending on the model
number. They allow users to configure the controller for a variety of input
sensors, to provide power for external signal conditioners or to lockout
front panel access to some functions.

To set any DIP switch:

• Remove the controller from the case by pressing firmly on the two release
tabs on one side or the top of the bezel until they unsnap. Then firmly
press the two release tabs on the opposite side or the bottom of the
control until they unsnap. You will need to gently rock the bezel back
and forth to release it from the chassis.

• Use the illustrations on the following pages to locate and set each DIP switch.

Figure 1.1 - Press
the release tabs to
remove the con­troller chassis.

Release

Tabs

A

W

PROCESS

1A 2A 1B 2B

CH A
CH B

SERIES 998

W

TL

DISPLAY

AUTO

MAN

MODE

Release

Tabs

W

A

TL

W

PROCESS

1A 2A 1B 2B

Release

Tabs

CH A
CH B

DSPY

MODE

AUTO

MAN

SERIES 998

Hardware Setup, Chapter 1

Release

Tabs

WATLOW Series 998 User’s Manual 1.1

DIP Switches

˜

NOTE:
The input 2 DIP
switch is mounted
upside down.

˜

1 - Set the input DIP
switches to match the
sensors you are using
in your application.
Only controllers with
model number 99__­22__-____ have input
DIP switches.

Input 2 DIP
(Channel B)
DIP

Input 1 DIP
(Channel A)
DIP

ON

ON

Controller Chassis

Rear View

Input 1 (Channel A) Input 2 (Channel B)

(99__-2___-____) (99__-_2__-____)

NOTE:
Only controllers
with the indicated
model numbers
have these DIP
switches.

Figure 1.2 ­Input DIP switches.

RTD

thermocouple: R, S or B

thermocouple: J, K, T, N, E, C, D, Pt2

0-20 or 4-20mA; 0-5, 1-5 or 0-10V

123

O
N

↑

123

O
N

↑

123

O
N

↑

123

O
N

↑

↑

N
O

123

↑

N
O

123

↑

N
O

123

↑

N
O

123

1.2 WATLOW Series 998 User’s Manual

Hardware Setup, Chapter 1

NOTE:
For other voltages
or current settings
contact the factory.

NOTE:
Only controllers
with the indicated
model numbers
have these DIP
switches.

2 - Set DIP switches for
outputs equipped with
an external signal
conditioner power
supply. Only controllers
with model number
99__-____-T___ or
99__-____-_T__ have an
external signal condi­tioner power supply.

(99

DIP Switches

Lockout
DIP

Output 3

Option Board and Dip

Control Chassis

Top View (996 & 998)

Left-side View (997 & 999)

Output 3 Output 4

__-____-T___) (99__-____-_T__)

ON

OFF

ONOFF

ONOFF

Output 4

Option Board and Dip

Figure 1.3 ­External signal con­ditioner power sup­ply DIPs.

12

O
N

↑

12

O
N

↑

12

O
N

↑

20V ± 5% @ 30mA

12V ± 5% @ 30mA

5V ± 5% @ 30mA

12

O
N

↑

12

O
N

↑

12

O
N

↑

3 - When the DIP switches are set, gently insert the controller chassis into
the case and push it firmly into place until all four tabs snap into place.

Hardware Setup, Chapter 1

WATLOW Series 998 User’s Manual 1.3

DIP Switches

ç

CAUTION:
The lockout DIP
switch makes the
Setup and Factory
menus unavailable.
Configure all the
Setup and Factory
menus before lock­ing them out.
Failure to do so
could result in dam­age to equipment in
the event of a setup
error.

4 - The lockout DIP switch
hides the Setup Menus (Input,
Output, Global and
Communications) and the
Factory Menus (Panel
Lockout, Diagnostics and
Calibration). All units have a
lockout DIP switch.

All controllers leave the
factory with both switches set
to off.

Lockout
DIP

Control Chassis

Top View (996 & 998)

Left-side View (997 & 999)

ON

OFF

Figure 1.4 ­Lockout DIP switch.

12

O
N

no hardware lockout or

↑

(Switch 1 has no effect.)

12

O
N

lockout Setup and Factory menus or

↑

(Switch 1 has no effect.)

Input

Panel

Lockout

Output Global

Diagnostics Calibration

Commu­nications

12

O
N

↑

12

O
N

↑

1.4 WATLOW Series 998 User’s Manual

Hardware Setup, Chapter 1

TLTL

W

W

A

PROCESS

1A 2A 1B 2B

CH A

CH B

DISPLAY

SERIES 998

MODE

AUTO

MAN

4.03"

(102mm)

2.18"

(55mm)

TL

W

W

A

PROCESS

CH A
CH B

MODE

SERIES 998

DSPY

AUTO

MAN

1A 2A 1B 2B

4.03"

(102mm)

2.18"

(55mm)

Chapter 2 Installation and Wiring

NOTE:
A minimum of 1.66”
(42.2mm) spacing
between panel
cutouts is recom­mended.

Figure 2.1a ­Series 998
Panel Cutout
Dimensions.

Panel Cutout

Maximum Panel

Thickness

0.38" (9.65mm)

3.62" + 0.03 -0.00
(92mm + 0.8)

1.77 + 0.02 -0.00
(45mm + 0.6)

NOTE:
Adjustable mount­ing brackets can
also be side mount­ed.

Figure 2.1b ­Series 998
Dimensions.

Installation and Wiring, Chapter 2

0.68"

(17 mm)

Panel

4.06"

(103 mm)

Adjustable

Mounting Bracket

WATLOW Series 998 User’s Manual 2.1

Installing

Panel

Adjustable

Mounting Bracket

Bezel

External Gasket

Mounting Collar

Release Tabs

Top and Bottom (996 or 998)
or Side (997 or 999) View

Mounting Slots

Side (996 or 998)
or Top and Bottom (997 or 999) View

˜

Installing the Series 998

Installing and mounting requires access to the back of the panel.

NOTE:
Removing the con­troller chassis from
its case makes
mounting easier.

Figure 2.2 ­Side and top view.

1. Make a panel cutout.

2. To remove the controller chassis from its case, press in firmly on the two
tabs on one side or the top of the bezel until they unsnap, then unsnap
the two tabs on the opposite side or the bottom. Pull the chassis out of
the case by gently rocking it.

3. Slide the case into the panel cutout. Check to see that the gasket is
not twisted, and is seated within the case bezel flush with the panel.
Slide the mounting collar over the back of the control.

2.2 WATLOW Series 998 User’s Manual

Installation and Wiring, Chapter 2

ç

CAUTION:
Follow the installa­tion procedure
exactly to guaran­tee a proper NEMA
4X seal. Make sure
the gasket between
the panel and the
rim of the case is
not twisted and is
seated properly.
Failure to do so
could result in dam­age to equipment.

Installing

4. Loosen the mounting bracket screws enough to allow for the mounting
collar and panel thickness. Place each mounting bracket into the
mounting slots (head of the screw facing the back of the controller).
Push each bracket backward then down to secure it to the control
case. To guarantee a proper NEMA 4X seal, Series 996 and 998

units (vertical) must have the mounting brackets located on either
side of the unit. When installing Series 997 and 999 units (horizon­tal) the brackets must be on the top and bottom of the unit.

5. Make sure the case is seated properly. Tighten the installation screws
firmly against the mounting collar to secure the unit. To ensure a

NEMA 4X seal, there should be no space between the bezel and
panel. Overtightening the screws will distort the case and make it diffi-

cult to remove or replace the controller.

6. Insert the controller chassis into its case and press the bezel until all
four tabs snap. Make sure the inside gasket is seated properly and not
twisted.

7. To release the mounting brackets, loosen the mounting bracket screws
and push the brackets forward, then pull it up and out.

Installation and Wiring, Chapter 2

WATLOW Series 998 User’s Manual 2.3

Wiring

Fuse

22

21

Earth Ground

11

L2L1

ç

WARNING:
To avoid potential
electric shock, use
National Electric
Code (NEC) safety
practices when
wiring and connect­ing this unit to a
power source and
to electrical sen­sors or peripheral
devices. Failure to
do so could result
in injury or death.

NOTE:
Input-to-output iso­lation is defeated
when the external
signal conditioner
power supply is
used to power a
transmitter con­nected to input 1 or
input 2.

Wiring the Series 998

Wiring options depend on the model number and DIP switch settings.
Check the terminal designation stickers on either side of the controller
and compare your model number to those shown here and with the
model number breakdown on the inside back cover of this manual.

Input-to-output Isolation

The Series 998 uses optical isolation between the analog inputs and the
controller outputs/digital input. This isolation provides a 500VÅ (ac) bar­rier to prevent ground loops when using grounded sensors and/or
peripheral equipment.

Here is a breakdown of the isolation barriers:

• Analog inputs 1 and 2 are grouped together.

• Outputs 1 through 4 and the standard event input are grouped togeth­er. This does not apply to Output 4 when configured as communications.

• The digital communications output (4) is separate from the above
groups.

Power Wiring

100 to 240VÅÅ(ac) nominal, (85 to 264 actual)

Vertical Package 99 8
Horizontal Package 99 9

24 to 28 V‡‡(ac/dc) nominal, (20 to 30 actual)

_ - _ _ _ _ - _ _ _ _
_ - _ _ _ _ - _ _ _ _

Figure 2.4 ­Power wiring.

ç

CAUTION:
The Series 998 will
not function with
two grounded ther­mocouple inputs.
Avoid using a
grounded thermo­couple for both
input 1 and input 2.
Failure to follow
this guideline could
result in damage to
equipment.

Vertical Package 99 6

_ - _ _ _ _ - _ _ _ _

Horizontal Package 99 7 _ - _ _ _ _ - _ _ _ _

Sensor Installation Guidelines

Thermocouple input: Extension wire for thermocouples must be of the
same alloy as the thermocouple itself to limit errors.

Using grounded thermocouples for both input 1 and input 2 may create
ground loop problems. To correct this problem, replace at least one of the
grounded thermocouples with an ungrounded thermocouple. If the appli­cation requires grounded thermocouples, use an isolated transmitter,
such as a Watlow Gordon 5702 isolated transmitter.

RTD input: Each 1Ω of lead wire resistance can cause a +2°F error when
using a two-wire RTD. A three-wire RTD sensor overcomes this problem.
All three wires must have the same electrical resistance (i.e., same gauge,
same length, multi-stranded or solid, same metal).

Maintain isolation between input 1 and input 2 to prevent a ground loop.
A ground loop may cause incorrect readings, dashes across the upper
display or the display of error codes.

Process input: Isolation must be maintained between input 1 and input

2. If both input 1 and input 2 are used as process inputs, a separate
power supply and transmitter must be used for each input. Output
option T (external signal conditioner power supply) can be used to supply
power for only one input.

2.4 WATLOW Series 998 User’s Manual

Installation and Wiring, Chapter 2

24

23

+24VÎ (dc)

10KΩ

4.99KΩ

OPTO
ISOLATOR

750Ω

.01µf

4.99KΩ

Internal Circuitry

Wiring

23 24

23 24

+

-

Event Input 1

Standard on all units

14 - 36VÎ (dc) Event Input 1 off (open)
0 - 3VÎ (dc) Event Input 1 on (closed)

OR

Wiring 0-20 and 4-20mA Process Inputs

Certain “transmitters” used in process input applications are producing
internal resistor failures in the Watlow Series 988 family of controllers.
This is only apparent with the Series 988 family 1/8 DIN units with
Process Inputs selected (0-20mA or 4-20mA dc only).

We are noticing that an external resistor is required to prevent a high
in-rush current which burns out the Series 988 family controllers’ 7-ohm
internal resistor. This high in-rush current occurs initially on “power-up.”
If the transmitter turns full on for a split second during power-up, the
available current weakens or damages the internal resistor.

Example: 20V / 7 ohms = 2,857mA (too much!).
The wiring diagram example below shows an application where a cus-

tomer is using a 4-20mA dc transmitter and power supply to feed the
input of a Series 988 controller. The Rx range (100 to 400 ohms) for the
external resistor is recommended. We suggest starting with 250 ohms.

Example: Customer is using a 24VÎ (dc) power supply to power up the
4-20mA dc transmitter that inputs to the Series 988 terminals 8 (-) and 10
(+). To figure out what the internal Series 988’s handling current is for the
0-20mA or 4-20mA dc input to the Series 988 controllers, we need to apply
Ohm’s Law: The square root of Watts divided by Resistance equals Current.
Applying that formula to the example below produces the following: Square
Root of (0.125 Watts / 7 ohms) = 134 mA dc (handling input current). This
is the acceptable input current for the Series 988 universal input board.

988 Process

Input Control

Figure 2.5 ­Process wiring
example.

Installation and Wiring, Chapter 2

4-20mA dc

Transmitter

R

Internal

Resistor

7Ω

1/8 Watt

+

—

x

100 to 400

ohms

—

+

+

24VÎ (dc)

Power Supply

—

Reminder, the input impedance of 7 ohms handles the majority of our
customer applications; the external resistor (Rx) is only for certain trans­ducers/transmitters that spike on power-up or power-down. Please make
sure your customer’s transmitter / transducer fall within our Series 988
family (1/8 DIN) of controllers’ Process Input specification of 7 ohms
input impedance.

WATLOW Series 998 User’s Manual 2.5

Wiring Example

➥

Series 146
Limit Control
146E-1601-3000

High­Temperature
Light

High-Limit
Mechanical
Control

Fuse

Mercury

Relay

Humidify

Dehumidify

Earthground

Fuse

L1
L2

L1
L2

12
13
14
15
16
17
18
19
20

8
9

10

21 22 11

Coil

123456789

10 11 12 131415 16 17

CNONC

Reset

L2

L2

L1

L2

L1

L2

Heater

Cooling
Fan

Wet Bulb

RTD Sensor

Dry Temp

RTD Sensor

Limit Sensor

Environmental

Chamber

Figure 2.6 ­System Wiring
Examples.

ç

WARNING:
To avoid potential
electric shock, use
National Electric
Code (NEC) safety
practices when
wiring and connect­ing this unit to a
power source and
to electrical sensors
or peripheral
devices. Failure to
do so could result
in injury or death.

ç

CAUTION:
To avoid damage to
property and equip­ment, use National
Electric Code (NEC)
standard wiring
practices to install
and operate the
series 998. Failure
to do so could
result in such dam­age.

2.6 WATLOW Series 998 User’s Manual

Installation and Wiring, Chapter 2

ç

WARNING:
To avoid damage to
property and equip­ment, and/or injury
or loss of life, use
National Electric
Code (NEC) stan­dard wiring prac­tices to install and
operate the Series

998. Failure to do so
could result in such
damage, and/or
injury or death.

Wiring Notes

L1 L2

earth ground

11

21 22

power

NOTE:
Sketch in your
application on this
page or a copy of
it. See wiring exam­ples in this chapter
and in the Appen­dix.

Figure 2.7 ­Wiring notes.

Installation and Wiring, Chapter 2

WATLOW Series 998 User’s Manual 2.7

9

10

+

-

9

10

8

S2

S1

S3

9

10

8

S2

S1

10

9-+

V

DC

O
N

↑

123

O
N

↑

123

O
N

↑

123

O
N

↑

123

O
N

↑

123

Channel A Input Wiring

NOTE:
Using a grounded
thermocouple for
both input 1 and
input 2 can cause
ground loop prob­lems.

NOTE:
Model number
99_ _-1 _ _ _-_ _ _ _
has no input 1 DIP
switch.

Figure 2.8a

— Thermocouple

Thermocouple only
99 _ _ - 1

_ _ _ - _ _ _ _

Universal signal conditioner
99 _ _ - 2 _ _ _ - _ _ _ _

Figure 2.8b

— RTD, 2- or 3-wire

Universal signal conditioner
99 _ _ - 2

_ _ _ - _ _ _ _

Dip Switch Setting

Jumper 9 to 10
for 2-wire RTD

J, K, T, N, C, E, Pt2, D
Dip Switch Setting

R, S, B
Dip Switch Setting

ç

CAUTION:
An external resistor
is required for
0-20mA and 4-20mA
process wiring to
prevent a high in­rush current which
could burn out the
controller’s 7-ohm
resistor. See page

2.4. for recommen­dations.

Figure 2.8c

— 0-5VÎÎ, 1-5VÎÎor 0-10VÎÎ(dc) Process

Universal signal conditioner
99 _ _ - 2 _ _ _ - _ _ _ _

Input impedance: 10KΩ

Figure 2.8d

— 0-20mA or 4-20mA Process

Universal signal conditioner
99 _ _ - 2 _ _ _ - _ _ _ _

Input impedance: 7Ω

Dip Switch Setting

Dip Switch Setting

mA

-

8

10

+

2.8 WATLOW Series 998 User’s Manual

Installation and Wiring, Chapter 2

Channel B Input Wiring

19
20

+

-

19

20

18

S2

S1

19

20

18S2S1

S3

20

18

-

+

mA

20

19-+

V

DC

O
N

↑

123

O
N

↑

123

O
N

↑

123

O
N

↑

123

O
N

↑

123

NOTE:
Using a grounded
thermocouple for
both input 1 and
input 2 can cause
ground loop prob­lems.

NOTE:
Model number
99_ _-_ 1 _ _-_ _ _ _
has no In1 DIP
switch.

Figure 2.9a — Thermocouple

Thermocouple only
99 _ _ - _ 1 _ _ - _ _ _ _

J, K, T, N, C, E, Pt2, D

Universal signal conditioner

Dip Switch Setting

99 _ _ - _ 2 _ _ - _ _ _ _

R, S, B
Dip Switch Setting

Figure 2.9b

— RTD, 2- or 3-wire

99 _ _ - _ 2 _ _ - _ _ _ _

Dip Switch Setting

Jumper
19 to 20

for 2-wire

RTD

ç

CAUTION:
An external resistor
is required for
0-20mA and 4-20mA
process wiring to
prevent a high in­rush current which
could burn out the
controller’s 7-ohm
resistor. See page

2.4. for recommen­dations.

Figure 2.9c

99 _ _ - _ 2

— 0-5VÎÎ, 1-5VÎÎ, 0-10VÎÎ(dc) Process

_ _ - _ _ _ _

Input impedance: 10KΩ

Dip Switch Setting

Figure 2.9d — 0-20mA or 4-20mA Process

99 _ _ - _ 2 _ _ - _ _ _ _

Input impedance: 7Ω

Dip Switch Setting

Installation and Wiring, Chapter 2

WATLOW Series 998 User’s Manual 2.9

Channel A Output Wiring

14

-

+

12

14

-

+

13

Figure 2.10a — AC Outputs

• Dual Electromechanical Relays without
Contact Suppression

Dual Form A, 2 Amps
Off-state impedance: 31MΩ

99 _ _ - _ _ E _ - _ _ _ _

• Dual Solid-state Relay without
Contact Suppression

Dual Form A, 0.5 Amps
Off-state impedance: 31MΩ

99 _ _ - _ _ K

Figure 2.10b

_ - _ _ _ _

— Dual Switched DC

99 _ _ - _ _ C _ - _ _ _ _

12

NO

13

COM

14

NO

12

+

-

13

14

23.5 to 30.6VÎ (dc)

+ VÎ

Internal Circuitry

External

External

External
Load 1A

Load

Fuse

Load

1500

1500

1A
L2

L1
L2
2A

+

External

-

Load 2A

12

Ω

13

Ω

14

Figure 2.10c

— 0-20mA and 4-20mA Process

Load impedance: 800Ω max.

99 _ _ - _ _ F

Figure 2.10d

_ - _ _ _ _

— 0-5VÎÎ, 1-5VÎÎand 0-10VÎÎ(dc) Process

Load impedance: 500Ω min.

99 _ _ - _ _ F

_ - _ _ _ _

2.10 WATLOW Series 998 User’s Manual

Installation and Wiring, Chapter 2

Channel B Output Wiring

15

+

-

17

16

+

-

17

External

Load

COM

L1

L2

Fuse

NO

15
16

17

NO

External

Load

L2

1B

2B

Figure 2.11a — AC Outputs

• Dual Electromechanical Relay without
Contact Suppression

Dual Form A, 2 Amps
Off-state impedance: 31MΩ

99 _ _ - _ _ _ E - _ _ _ _

• Dual Solid-state Relay without
Contact Suppression

0.5 Amps
Off-state impedance: 31MΩ

99 _ _ - _ _ _ K

Figure 2.11b

99 _ _ - _ _ _ C

Figure 2.11c

- _ _ _ _

— Dual Switched DC

- _ _ _ _

— 0-20mA and 4-20mA Process

Load impedance: 800Ω max.

99 _ _ - _ _ _ F

- _ _ _ _

15
16
17

+

Load

1b

-

23.5 to 30.6VÎ (dc)

+ VÎ

Internal Circuitry

1500

1500

+

Load

2b

-

15

Ω

16

Ω

17

Installation and Wiring, Chapter 2

Figure 2.11d

— 0-5VÎÎ, 1-5VÎÎand 0-10VÎÎ(dc) Process

Load impedance: 500Ω min.

99 _ _ - _ _ _ F

- _ _ _ _

WATLOW Series 998 User’s Manual 2.11

Output 3 Wiring

External

Load

COM

L1

L2

Fuse

NO Form A

1
2

NC Form B

or

1
2

External

Load

-

+ VÎ

Internal Circuitry

1
2

790Ω

19 to 32VÎ (dc)

+

1
2

+

-

1
2

+

-

+V

-V

Transmitter
4-20mA out

Input

1 or 2

+

-

Figure 2.12a — AC Outputs

• Solid-state Relay with

Contact Suppression

0.5 Amps
Off-state impedance: 20KΩ min.

99 _ _ - _ _ _ _ - B

• Electromechanical Relay without

Contact Suppression

Form A or B, 5 Amps
Off-state impedance: 31MΩ

99 _ _ - _ _ _ _ - J _ _ _

Figure 2.12b

Minimum load resistance: 500Ω

99 _ _ - _ _ _ _ - C

_ _ _

Form A or B
Alarm Jumper Settings
(Top View)

— Switched DC

_ _ _

• Solid-state Relay without

Contact Suppression

0.5 Amps
Off-state impedance: 31MΩ

99 _ _ - _ _ _ _ - K _ _ _

Form B

Form A

Figure 2.12c

0-20mA, 4-20mA

Load impedance: 600Ω max.

99 _ _ - _ _ _ _ - M _ _ _

0-5VÎÎ, 1-5VÎÎor 0-10VÎÎ(dc)

NOTE:
Input-to-output iso­lation is defeated
when the external
transmitter power
supply is used to
power a transmitter
connected to input
1 or input 2.

Load impedance: 500Ω min.

99 _ _ - _ _ _ _ - N

Figure 2.12d — External Transmitter Power Supply

99 _ _ - _ _ _ _ - T _ _ _
See Chapter 1 for DIP switch location and set-

tings.

2.12 WATLOW Series 998 User’s Manual

— Process Retransmit

_ _ _

Installation and Wiring, Chapter 2

Output 4 Wiring

External

Load

COM

L1

L2

Fuse

NO

5
6

NC

(7 for D & E outputs only)

7

5

External

Load

6

+

+ VÎ

Internal Circuitry

5
6
7

790

19 to 32VÎ (dc)

7

-

COM

Ω

5

6

+

-

+V

-V

Transmitter
4-20mA out

Input

1 or 2

+

-

Figure 2.13a

— AC Outputs

• Solid-state Relay with

Contact Suppression

0.5 Amps
Off-state impedance: 20KΩ min.

99 _ _ - _ _ _ _ - _ B

_ _

• Solid-state Relay without

Contact Suppression

0.5 Amps
Off-state impedance: 31MΩ

99 _ _ - _ _ _ _ - _ K

_ _

• Electromechanical Relay with

Contact Suppression

(On NO and COM contacts only)
Form C, 5 Amps
Off-state impedance: 20KΩ min.

99 _ _ - _ _ _ _ - _ D _ _

• Electromechanical Relay with­out

Contact Suppression

Form C, 5 Amps
Off-state impedance: 31MΩ

99 _ _ - _ _ _ _ - _ E

_ _

NOTE:
Input-to-output iso­lation is defeated
when the external
transmitter power
supply is used to
power a transmitter
connected to input
1 or input 2.

Installation and Wiring, Chapter 2

Figure 2.13b

— Switched DC, Open Collector

Minimum load resistance: 500Ω

99 _ _ - _ _ _ _ - _ C _ _

Figure 2.13c

— External Transmitter Power Supply

99 _ _ - _ _ _ _ - _ T _ _
See Chapter 1 for DIP switch location and settings.

For data communications wiring refer to How to Use
Data Communications with the Watlow Series 988 Family Controls.

WATLOW Series 998 User’s Manual 2.13

Notes

2.14 WATLOW Series 998 User’s Manual

Installation and Wiring, Chapter 2

Chapter 3 Keys and Displays

Upper Display

Indicates either actual process
value for channel A or channel
B, the operating prompt values,
or error codes. When powering
up, the display will be blank for
3 seconds. Red or green, 0.4”
(10mm) high, seven-segment,
four-digit LED display.

CH A Indicator Light

When lit, if the CH B light is not
on, the channel A process value
is shown in the upper display
and the channel A set point
value is shown in the lower dis­play. When both CH A and CH
B lights are on, the upper dis­play shows the channel A

1A 2A 1B 2B

CH A
CH B

process value and the lower dis­plays shows the channel B
process value.

CH B Indicator Light

When lit, if the CH A light is not
on, the channel B process value
is shown in the upper display

SERIES 998

and the channel B set point
value is shown in the lower dis­play. When both CH A and CH
B lights are on, the upper dis­play shows the channel A
process value and the lower dis­play shows the channel B
process value.

Up-arrow Key >

Increases the value of the displayed prompt. A
light touch increases the value by one. Holding the
key down increases the value at a rapid rate. New
data does not take effect for five seconds or until
the Mode µ or Display ∂ key is pressed.

Down-arrow Key <

Decreases the value of the displayed prompt. A
light touch decreases the value by one. Holding the
key down decreases the displayed value at a rapid
rate. New data does not take effect for five seconds
or until the Mode µ or Display ∂ key is
pressed.

Up-arrow + Down-arrow Keys

Press simultaneously for three seconds to enter
the Setup Menu. Continue to press both keys for
another three seconds to enter the Factory Menu.

A

TL

W

PROCESS

DISPLAY

Lower Display

Indicates the channel A or
channel B set point, or channel
B process value, menu
prompts, or alarm codes. Red
or green, 0.3” (8mm) high,

W

seven-segment, four-digit LED
display.

1A, 2A, 1B, 2B Indicator
Lights

These lights indicate when out­put 1A, 2A, 1B or 2B is active.

Display Key ∂

The Display key is used to
select which channel A and/or
B parameter to displayed. On
initial power-up the upper dis­play shows the channel A

AUTO

MAN

MODE

process value and the lower
display shows the channel A set
point value and the CH A light
is on. One press of the Display
key lights CH B and the upper
display shows the channel B
process value and the lower
display shows the channel B
set point value. A second press
of the key lights both CH A and
CH B, and the upper display
shows the channel A process
value and the lower display
shows the channel B process
value. See the next page for

more information on the Display Loop.

Auto/Man Key å

Used to switch from auto to manual control or vice
versa. Also used to reset alarms.

Mode Key µ

Steps the control through the menus. New data is
entered once the Mode key is pressed.

Mode+Up-arrow Key µ + >

To move backwards through the menus, hold
down the Mode key, then press the Up-arrow key
to scroll. The Mode key must be pressed first and
held before the Up-arrow key will begin scrolling.
Scrolling is disabled once the keys are released or
you reach the top of the menu.

Keys and Displays, Chapter 3

Figure 3.1 ­Series 998 Keys and
Displays.

WATLOW Series 998 User’s Manual 3.1

Display Loop

NOTE:
Lower display alter­nately flashes
[`rP`] and lower
display value when
ramping is in
process.

Display Key and Loop

On power up, the Series 998 displays the channel A set point value in the
lower display and the channel A process value in the upper display and
the CH A (channel A) indicator light is on. Press the Display key once to
view the channel B set point and process values (CH B will be lit). Press
the Display key once again and channel A process value is displayed in
the upper display and channel B process value is displayed in the lower
display. At this point, both CH A and CH B will be lit. Press the Display
key again to display units.

Any point in any menu, if no key is pressed for one minute the display
returns to displaying the channel A process and set point.

Figure 3.2 ­The Display Loop.

Display Loop

Channel A

Process

[`75]

[100]

Channel A

Set Point

∂

Channel B

Process

[`80]

[125]

Channel B

Set Point

∂

Channel A

Process

[`75]

[`80]

Channel B

Process

Display Loop Parameters

Channel A Process and Set Point: The channel A process value is shown
in the upper display. The set point is shown in the lower display, it sets
the operating set point for the channel A control outputs. If channel A is
in manual mode the set point is in percent output.

Range: [`rL1] to [`rH1] in auto mode

[-100] % to [`100] % in manual mode (heat/cool)
[```0] % to [`100] % in manual mode (heat only)
[-100] % to [```0] % in manual mode (cool only)

Default: depends on input 1 range and type

Channel B Process and Set Point: The channel B process value is
shown in the upper display. The set point is shown in the lower display, it
sets the operating set point for the channel B control outputs. If channel
B is in manual mode the set point is in percent output.

Range: [`rL2] to [`rH2] in auto mode

[-100] % to [`100] % in manual mode (heat/cool)
[```0] % to [`100] % in manual mode (heat only)
[-100] % to [```0] % in manual mode (cool only)

Default: depends on input 2 range and type

Process A and Process B: The channel A process value is displayed in
the upper display with channel B process value displayed in the lower
display.

Range: depends on input types
Default: none

Units: Shows the units associated with the temperature value. This para­meter shows what the [`C-F] (Global Menu) is set to.

Range: [``°F] or [``°C]
Default: none
Hidden if: input 1 and input 2 are process inputs

∂

∂

[```]

[`°F]

Process

Units

3.2 WATLOW Series 998 User’s Manual

Keys and Displays, Chapter 3

TL

W

W

A

PROCESS

1A 2A 1B 2B

CH A
CH B

DISPLAY

SERIES 998

MODE

AUTO

MAN

TL

W

W

A

PROCESS

DISPLAY

MODE

1A 2A 1B 2B

CH A
CH B

SERIES 998

AUTO

MAN

Chapter 4 The Setup Menus

Navigating the Setup Menus

To reach the Setup Menus, begin in the Display Loop and press both the
Up-arrow > and Down-arrow < keys for three seconds. The Setup
Menu prompt [`SEt] will appear in the lower display, and the Input Menu
prompt [InPt] will appear in the upper display. The four Setup Menus
are: Input [InPt]; Output [OtPt]; Global [GLbL]; and Communications
[COM]. Use the Up-arrow > or Down-arrow < key to select a menu
and the Mode key µ to step through a menu. The Communications

NOTE:
Press the Display
key ∂ to return to
the Display Loop
from any point in
any menu.

Menu appears only on units equipped with the data communications
option (99__-____-_R__ or 99__-____-_S__).

You will not see every prompt in any of these menus. The unit’s configura­tion and model number determine which prompts appear. After stepping
through each menu, the Series 998 returns to the Setup Menu prompt.
Use the Up-arrow or Down-arrow key to select the next menu, or use the
Mode key to advance through the same menu again. To move backwards
through the menu hold the Mode key down and press the Up-arrow key.
Use the Up-arrow or Down-arrow key to change the prompt setting.

Refer to the Appendix for model number options. For additional informa­tion about communications and the communications prompts, refer to the
supplemental manual Data Communications with the Watlow Series 988

Family of Controllers.

❶ Begin in the Display Loop, and press the Up-arrow

> and Down-arrow < keys simultaneously to
reach the Setup menus.

NOTE:
The lockout DIP
switch hides the

>>

>

>

Setup menus. See
Chapter 1.

[Inpt]

[`SEt]

[Otpt]

[`SEt]

[GLbl]

[`SEt]

[COM]

[`SEt]

Input Output Global Communications
Menu Menu Menu Menu
p. 4.2 p. 4.16 p. 4.32 p. 4.38

❷ Press the Up-arrow key > to select one of the

Setup menus.

Figure 4.1 ­Navigating the
Setup menus.

Setup Menus, Chapter 4

WATLOW Series 998 User’s Manual 4.1

Setup-Input

TLTL

W

W

A

PROCESS

DISPLAY

MODE

1A 2A 1B 2B

CH A
CH B

SERIES 998

AUTO

MAN

Reaching the Input Menu

❸ Select the Input Menu, then

press the Mode key µ to step
through the prompts.

>>

>

[```)]

[DEC1]

❹ Press the Up-arrow key > or

the Down-arrow key < to select
one of the prompt values.

[``)0]

[DEC1]

[`)00]

[DEC1]

[)000]

[DEC1]

>

→ [InPt] Input Menu

[`SEt] Setup Menus

µ

?

↓

[`In1] Input 1 (page 4.5)

µ

↓ ?

[dEC1] *Decimal 1

µ

↓ ?

[`rL1] Range Low 1

µ

↓ ?

[`rH1] Range High 1

µ

↓ ?

[CAL1] Calibration Offset 1

µ

↓ ?

[rtd1] *RTD Calibration Curve 1

µ

↓ ?

[Ftr1] Input 1 Software Filter

µ

↓ ?

[`In2] *Input 2 (page 4.10)

µ

↓ ?

[deC2] *Decimal 2

µ

↓ ?

[`rL2] *Range Low 2

µ

↓ ?

[`rH2] *Range High 2

µ

↓ ?

[CAL2] *Calibration Offset 2

µ

↓ ?

[rtd2] *RTD Calibration Curve 2

µ

↓ ?

[Ftr2] *Input 2 Software Filter

µ

↓ ?

[Lin2] *Input 2 Linearization

µ

↓ ?

←µ [`Alt] *Altitude

Enter your settings,
from the controller’s
upper display.

Figure 4.2 ­The Input Menu.

4.2 WATLOW Series 998 User’s Manual

*Prompts may not appear, depending
on controller configuration.

Setup Menus, Chapter 4