Watlow PM LEGACY PM3 User manual

User Guide
Registered Company
Winona, Minnesota USA
ISO 9001
ISO 9001
TOTAL
3 Year Warranty
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Limit Controller
10-42072 Rev. -, July 2020, Made in the U.S.A.
1241 Bundy Boulevard., Winona, Minnesota USA 55987
Phone: [phone], Fax: [phone]
http://www.watlow.com
1/32 DIN
Available Soon
PM6
PM3
For Configurations:
PM(3,6)(L,M)_ _ _-_A_ _G_ _

Warranty Information
The PM LEGACY™ Limit Controller is manufactured by ISO 9001-registered processes and is backed
by a three-year warranty to the first purchaser for use, providing that the units have not been mis-
applied. Since Watlow has no control over their use, and sometimes misuse, we cannot guarantee
against failure. Watlow’s obligations hereunder, at Watlow’s option, are limited to replacement, repair
or refund of purchase price, and parts which upon examination prove to be defective within the war-
ranty period specified. This warranty does not apply to damage resulting from transportation, alter-
ation, misuse or abuse. The purchaser must use Watlow parts to maintain all listed ratings.
Technical Assistance
If you encounter a problem with your Watlow controller, review your configuration information to verify
that your selections are consistent with your application: inputs, outputs, alarms, limits, etc. If the prob-
lem persists, you can get technical assistance from your local Watlow representative (see back cover),
by e-mailing your questions to [e-mail] or by dialing [phone] between 7
a.m. and 5 p.m., Central Standard Time (CST). Ask for an Applications Engineer. Please have the follow-
ing information available when calling:
Complete model number
All configuration information
User's Guide
Factory Page
Return Material Authorization (RMA)
1. If you are an End User, and this PM is installed in an OEM System, please contact the OEM to get
the PM repaired. If you are an OEM or Watlow Distributor, please go to www.watlow.com/rma to
start the RMA process. Watlow Customer Service will then respond back with the RMA number
via an email.
2. A Return Merchandise Authorization number from the Customer Service Department is required
when returning any product for credit, repair or evaluation. Make sure the Return Merchandise
Authorization number is on the outside of the carton and on all paperwork returned. Ship on a
Freight Prepaid basis.
3. After we receive your return, we will examine it and try to verify the reason for returning it.
4. In cases of manufacturing defect, we will enter a repair order, replacement order or issue credit
for material returned. In cases of customer misuse, we will provide repair costs and request a pur-
chase order to proceed with the repair work.
5. To return products that are not defective, goods must be in new condition, in the original boxes
and they must be returned within 120 days of receipt. A 20 percent restocking charge is applied
for all returned stock controls and accessories.
6. If the unit cannot be repaired, you will receive a letter of explanation and be given the option to
have the unit returned to you at your expense or to have us scrap the unit.
7. Watlow reserves the right to charge for no trouble found (NTF) returns.
Copyrights - Patents Pending
This PM LEGACY™ Limit User’s Guide is copyrighted by Watlow Electric, Inc., © July 2020 with all
rights reserved.

Watlow PM LEGACY™ Limit Controller •3 • Table of Contents
TC
Table of Contents ..............................................3
Chapter 1: Overview ...........................................6
Available PM LEGACY™ Limit Literature and Resources .............6
Introduction.................................................6
Feature Benefits ............................................6
A Conceptual View of the PM ..................................7
Overview .................................................7
Inputs ...................................................7
Internal Functions ..........................................8
Outputs ..................................................8
Input Events and Output Events..............................10
Chapter 2: Install & Wiring .....................................12
Installation.................................................12
Dimensions ................................................14
1/32 DIN (PM3) ...........................................14
1/32 DIN (PM3) Recommended Panel Spacing ..................14
1/16 DIN (PM6) ..........................................15
1/16 DIN (PM6) Recommended Panel Spacing ..................15
Wiring ..................................................16
Chapter 3: Keys and Displays............................34
Responding to a Displayed Message ...........................35
Chapter 4: Home Page ........................................36
Changing the Set Point......................................38
Modifying the Home Page ...................................38
Modifying the Display Pairs ..................................38
Conventions Used in the Menu Pages ..........................40
Display...................................................40
Communication Protocols....................................41
Modbus Introduction to the Modbus Protocol ....................41
Profibus DP ...............................................42
Chapter 5: Operations Page ...................................43
Analog Input Menu .........................................44
Digital Input/Output Menu....................................45
Limit Menu. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Alarm Menu...............................................46
Chapter 6: Setup Page ........................................48
Analog Input Menu .........................................51
Digital Input/Output Menu....................................54
Limit Menu. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Output Menu ..............................................60
Alarm Menu...............................................60
Function Key ..............................................64
Global Menu ..............................................65
Communications Menu......................................66
Table of Contents

Watlow PM LEGACY™ Limit Controller •4 • Table of Contents
TC
Chapter 7: Factory Page.......................................74
Custom ..................................................75
Lock Menu ...............................................76
Unlock Menu..............................................78
Diagnostics Menu ..........................................79
Calibration Menu...........................................81
Chapter 8: Features ...........................................83
Changing PM Integrated Model Number to PM Express..............83
Saving and Restoring Settings ..................................84
Programming the Home Page ..................................85
Inputs .....................................................85
Calibration Offset ..........................................85
Calibration ................................................86
Filter Time Constant ........................................88
Sensor Selection ...........................................88
Scale High and Scale Low ...................................88
Range High and Range Low..................................89
Outputs ....................................................89
Retransmitting a Process Value or Set Point .....................89
Resetting a Tripped Limit ......................................89
Alarms.....................................................90
Process Alarms ............................................90
Set Points ................................................90
Hysteresis ................................................90
Latching..................................................91
Silencing .................................................91
Blocking .................................................91
Using Lockout and Password Security ...........................91
Using Lockout Method 1 (Read and Set Lock) ...................91
Using Lockout Method 2 (Password Enable) .....................93
Modbus - Using Programmable Memory Blocks....................95
CIP - Communications Capabilities ..............................96
CIP Implicit Assemblies .....................................97
Profibus DP - (Decentralized Peripherals) .........................96
Software Configuration........................................97
Using PM LEGACY™ Limit Configurator Software ................98
Chapter 9: Appendix ....................................... 102
Troubleshooting Alarms, Errors and Control Issues.................102
Modbus - Programmable Memory Blocks ........................107
CIP Implicit Assembly Structures...............................110
PM Specifications...........................................112
Ordering Information for Limit Controller Models...................118
Declaration of Conformity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Bluetooth Enabled Product Statement. . . . . . . . . . . . . . . . . . . . . . . . . . 121
Table of Contents (cont.)

Safety Information
We use note, caution and warning symbols throughout this book to draw your attention to important
operational and safety information.
A “NOTE” marks a short message to alert you to an important detail.
A “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 applica-
tion.
A “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 electrical hazard symbol, (an exclamation point in a triangle) precedes an electric shock hazard
CAUTION or WARNING safety statement.
Symbol Explanation
CAUTION – Warning or Hazard that needs further explanation than label on unit
can provide. Consult User's Guide for further information.
ESD Sensitive product, use proper grounding and handling techniques when
installing or servicing product.
Unit protected by double/reinforced insulation for shock hazard prevention.
Do not throw in trash, use proper recycling techniques or consult manufacturer for
proper disposal.
Enclosure made of Polycarbonate material. Use proper recycling techniques or
consult manufacturer for proper disposal.
Unit can be powered with either alternating current (ac) voltage or direct current
(dc) voltage.
Unit is a Listed device per Underwriters Laboratories®. It has been evaluated to
United States and Canadian requirements for Process Control Equipment. UL
61010 and CSA C22.2 No. 61010. File E185611 QUYX, QUYX7. See: www.
ul.com
Unit is compliant with European Union directives. See Declaration of Conformity
for further details on Directives and Standards used for Compliance.
Unit has been reviewed and approved by Factory Mutual as a Temperature Limit
Device per FM Class 3545 standard. See: www.fmglobal.com
Unit has been reviewed and approved by CSA International for use as
Temperature Indicating-Regulating Equipment per CSA C22.2 No. 24. See: www.
csa-international.org
Unit has been reviewed and approved by ODVA for compliance with DeviceNet
communications protocol. See: www.odva.org

Watlow PM LEGACY™ Limit Controller •6 •Chapter 1 Overview
Chapter 1: Overview
1
Introduction
The Watlow® LEGACY™ SERIES panel mount controller is an industry leading PID controller that al-
lows optimal performance utilizing simple control and menu functionality without complex features. It
is ideally suited for basic applications and usage levels.
The LEGACY™ includes one universal input and an option for up to two outputs and is available in
1/32, and 1/16 DIN panel mount packages. It can be ordered as a PID process controller or as a ded-
icated over and under-temperature limit controller. A single PM controller can carry out several func-
tions at the same time, for instance (but not limited to), PID control, checking for a limit condition,
monitoring for several different alarm situations, etc... To ensure that the application requirements are
being met, it is important to first give thought to each external process and then configuring the con-
troller’s internal functions to properly accommodate the application requirements.
Available PM LEGACY™ Limit Literature and Resources
Document Title and Part Number Description
Contact Watlow Directly: For technical assistance contact Watlow at:
www.watlow.com Or call at: 1-800-WATLOW2 Or
(1-800-928-5692) Or email at: [e-mail]
PM6 LEGACY™ Express Limit Con-
troller Quick Start Guide Document
No. 10-41692,
Part No. 2126-4403
A Quick Start Guide to help you get your controller set up is
available for download at https://www.watlow.com/resourc-
es-and-support/Technical-Library/. Many other documents
are available in Watlow’s Technical library.
PM LEGACY™ Series Panel Mount
Controller Specification Sheet
This Specifications Sheet describes the PM LEGACY™ Se-
ries hardware options, features, benefit ts and techni-
cal specifications. Available at: https://www.watlow.com/re-
sources-and-support/Technical-Library/. Many other helpful
documents are available in Watlow’s Technical library.

Watlow PM LEGACY™ Limit Controller •7 •Chapter 1 Overview
Figure 2: Input Terminal Connections
Shown Here
Overview
A Conceptual View of the PM
The flexibility of the PM software and hardware
allows for a large range of configurations. Ac-
quiring a better understanding of the controller’s
overall functionality and capabilities while at the
same time planning out how the controller can be
used will deliver maximum effectiveness in your
application.
It is useful to think of the controller in terms of
functions; there are internal and external func-
tions. An input and an output would be considered
external functions where the limit, PID or alarm
function would be an internal function. Information
flows from an input function to an internal func-
tion to an output function when the controller is
properly configured. A single PM controller can
carry out several functions at the same time, for
instance (but not limited to), checking for a limit
condition, monitoring for several different alarm
situations, etc... To ensure that the application
requirements are being met, it is important to first
give thought to each external process and then
configuring the controller’s internal functions to
properly accommodate the application require-
ments.
Inputs
The inputs terminal connections are located on the
back side of the controller. See Figure 2. The con-
troller, properly wired and configured will provide
the information that any given programmed proce-
dure can act upon. In a simple form, this informa-
tion may come from an operator pushing a button
or from a sensor monitoring the temperature of a
part being heated or cooled.
Each analog input typically uses a thermocouple
or RTD to read the process temperature. It can
also read volts, current or resistance, allowing it to
use various devices to read a wide array of val-
ues. The settings in the Analog Input Menu (Setup
Page) for each analog input must be configured to
match the device connected to that input.
Figure 1: PM6 Controller Shown Here
A PM with digital input/output (DIO) hardware in-
cludes two sets of terminals where each of which
can be used as either an input or an output. Each
pair of terminals must be configured to function
as either an input or output with the direction pa-
rameter in the Digital Input/Output Menu (Setup
Page). Each digital input reads whether a device
is active or inactive.
The Reset Key on the front panel of the PM also
operates as a digital input by toggling the func-
tion assigned to it in the Digital Input Function
parameter in the Reset Key Menu (Set-up Page).

Watlow PM LEGACY™ Limit Controller •8 •Chapter 1 Overview
Figure 3: Output Wiring Example
(Overview Continued)
Internal Functions
The controller will use input signals to calculate
a value and then perform an operation. A sample
of some functions may be as simple as:
• Detect a failure of the primary sensing device
and trip a contactor to remove power from the
heating element.
• Reading a digital input to set a state to true or
false.
• Evaluate an incoming temperature to determine
an alarm state (on or off).
• Compare an input value to the set point and
calculate the optimal power for a heater.
To set up a function, it’s important to define the
source, or instance, to use. For example, if the
control is equipped with DIO they can be con-
figured to respond to an alarm. If configured
as such, the digital output must be tied to the
desired alarm instance (1 to 4). Using this as
an example, the Function for the digital output
would be defined as an Alarm where the Instance
would be selected as 1, 2, 3, or 4 corresponding
to the alarm instance that will drive the output.
Keep in mind that a function is a user-pro-
grammed internal process that does not execute
any action outside of the controller. To have any
effect outside of the controller, an output must be
configured to respon
Outputs
The Output Wire Terminals are located on the
back side of the controller. See Figure 3. The
Outputs properly wired and configured can
perform various functions or actions in response
to information provided by a function such as,
removal of the control voltage to a contactor;
operating a heater, turning a light on or off, un-
locking a door, etc.
Assign a Function to any available output on the
Setup Page within the Output Menu or Digital
Input/Output Menu. Then select which instance
of that function will drive the selected output.
For example, you might assign an output to
respond to alarm 4 (instance 4).
You can assign more than one output to re-
spond to a single instance of a function. For ex-
ample, alarm 2 could be used to trigger a light
connected to output 1 and a siren connected to
digital output 5.

Watlow PM LEGACY™ Limit Controller •9 •Chapter 1 Overview
Features and Benefits
Simplified Menu
• Fits basic applications with a user-friendly
interface supported by two menus and a stream-
lined list of parameters.
• Eliminates user complexity often experienced
with more advanced controllers and unnecessary
features.
• Reduces user training costs and user program-
ming errors
PID Auto-Tune
• Provides auto-tune for fast, efficient start-up
Standard Bus Communications
• Allows easy product configuration via PC com-
munications protocol and free software.
• Saves time, simplifies programming process
and improves reliability of controller setup
Factory Mutual (FM) Approved Over and Un-
der Limit with Auxiliary Outputs.
• Increases user and equipment safety for over
and under-temperature conditions.
Function Key
• Enables simple, one-touch operation of us-
er-defined, repetitive activities
Touch-Safe Package
• Increases installer and operator safety
• Complies with IP2X requirements
EZ-LINK™ Mobile Application for iPhone®
and Android™
• Expedites controller setup with intuitive naviga-
tion
• Simplifies setting parameters with plain text
names and descriptions
• Connects quickly and easily via Bluetooth®
wireless communications
SMOOTH TOUCH™ Keypad
• Eliminates contamination points on the front of
the controller.
• Prevents premature failure of mechanical com-
ponents
• Creates a better seal on front panel.
• Ensures an easy to clean surface.
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
P3T Armor Sealing System
• Compiles to NEMA 4X, IP66 and IP67 specifi-
cations
• Allows controller to be cleaned and washed
• Certified UL® 50 Type X4X indoor applica-
tions.
Consistent Termination Labeling (CTL)
Connection System
• Simplifies switching between products
• Speeds up user’s system documentation
Three-Year Warranty
• Demonstrates Watlow’s reliability and product
support
High-Amperage Power Control Output (1/16
DIN only)
• Drives 15 ampere resistive loads direct
• Reduces component count
• Saves panel space and simplifies wiring
• Reduces cost of ownership

Watlow PM LEGACY™ Limit Controller •10 •Chapter 1 Overview
PM LEGACY™ Limit PM Models - System Diagram
(with communications options 2, 3, 5 or 6)
Universal Sensor Input, Configuration Communications,
Red/Green 7-Segment Display
Note:
Number of inputs and outputs and various combinations of the same will vary
depending upon part number; see ordering matrix for more detail.
Output Status
Indicators
5
6
1
3
2
4
Zone
Address
Indicators
Channel
Indicates Zone
Address & Channel*
Indicates I/O
Status
* Channel indicator available
on PM4/8/9 only
Supervisory
&
Power
Board
Slot C
Limit
Controller
Board
Slot A Output 2
Form A mechanical (5 A) relay
Output 1
None, Switched dc/open collector,
Form C mechanical (5 A) relay
Off, Limit,
Alarm
EZ-ZONE PM Enhanced Limit Controller System Diagram
with Communications
Function Key
Programmable Functions
Digital Output (or Input) 5 & 6
(optional) None, Switched dc
Off,
Alarm
Network
Remote User Interface
Personal Computer
Programmable Logic Controller
Human Machine Interface
EIA 485 Communications
Standard Bus, Modbus RTU (optional)
Communi-
cations
Board
(optional)
Slot B
Analog Input 1
Off, Thermocouple, RTD (100Ω, 1kΩ),
Thermistor (5kΩ, 10kΩ, 20kΩ, 40kΩ),
Process (V, mV, mA, 1k potentiometer)
Digital Input (or Output) 5 & 6
(optional) none, switch, volts dc
None
Limit reset
Loop & alarms off
Silence alarm
Force Alarm
Lock keypad
Restore user settings
Input Sensor
Input
Functions
Output
Functions
Communications
EIA-232/485 Modbus RTU, Ethernet/IP,
DeviceNet, Modbus TCP, Profibus
Limit
Input Events and Output Events
Input events are internal state input event 2. The setting of Digital Input Function (Setup Page, Digital Input/Out-
put Menu) does not change the relationship between the input and the event. An input will still control the input
event state, even if Digital Input Function is set to None.

Watlow PM LEGACY™ Limit Controller •11 •Chapter 1 Overview
PM LEGACY™ Limit PM Models - Input/Output
(no communications options 2, 3, 5 or 6)
Universal Sensor Input, Configuration Communications,
Red/Green 7-Segment Display
Note:
Number of inputs and outputs and various combinations of the same will vary
depending upon part number; see ordering matrix for more detail.
Output Status
Indicators
5
6
1
3
2
4
Zone
Address
Indicators
Channel
Indicates Zone
Address & Channel*
Indicates I/O
Status
* Channel indicator available
on PM4/8/9 only
Analog Input 1
Off, Thermocouple, RTD (100Ω, 1kΩ),
Thermistor (5kΩ, 10kΩ, 20kΩ, 40kΩ),
Process (V, mV, mA, 1k potentiometer)
Output 3
None, Switched dc/open collector, Form
C mechanical relay (5 A), Form A solid-
state relay (0.5 A), Process (V, mA)
Output 4
None, Switched dc/open collector, Form
A solid-state relay (0.5 A), or Form A
mechanical relay (5 A)
EZ-ZONE™ PM Enhanced Limit Controller
Off,
Alarm
Input
Functions
Output
Functions
Off, Alarm,
Retransmit
Network
Remote User Interface
Personal Computer
Programmable Logic Controller
Human Machine Interface
None
Limit reset
Loop & alarms off
Silence alarm
Force Alarm
Lock keypad
Restore user settings
Input Sensor
Function Key
Programmable Functions
Supervisory
&
Power
Board
Slot C
Limit
Controller
Board
Slot A
Output
Board
(optional)
Slot B
Output 2
Form A mechanical (5 A) relay
Output 1
None, Switched dc/open collector,
Form C mechanical (5 A) relay
Off, Limit,
Alarm
Digital Output (or Input) 5 & 6
(optional) None, Switched dc
Off,
Alarm
Limit
Digital Input (or Output) 5 & 6
(optional) none, switch, volts dc
EIA 485 Communications
Standard Bus, Modbus RTU (optional)

Watlow PM LEGACY™ Limit Controller •12 •Chapter 1 Overview
PM LEGACY™ Limit All Models System Diagram
(No communications options 2, 3, 5 or 6)
Universal Sensor Input, Configuration Communications,
Red/Green 7-Segment Display
Analog Input 1
Off, Thermocouple, RTD (100Ω, 1kΩ),
Thermistor (5kΩ, 10kΩ, 20kΩ, 40kΩ),
Process (V, mV, mA, 1k potentiometer)
Output Status
Indicators
5
6
1
3
2
4
Zone
Address
Indicators
Channel
Indicates Zone
Address & Channel*
Indicates I/O
Status
* Channel indicator available
on PM4/8/9 only
Note:
Number of inputs and outputs and various combinations of the same will vary
depending upon part number; see ordering matrix for more detail.
Supervisory
&
Power
Board
Slot C
Limit
Controller
Board
Slot A
EZ-ZONE™ PM Limit Controller
Input
Functions
Output
Functions
Network
Remote User Interface
Personal Computer
Programmable Logic Controller
Human Machine Interface
None
Limit reset
Loop & alarms off
Silence alarm
Force Alarm
Lock keypad
Restore user settings
Input Sensor
EIA 485 Communications
Standard Bus, Modbus RTU (optional)
Function Key
(Not available on 1/32 DIN)
Programmable Functions
Digital Input (or Output) 5 & 6
(optional) none, switch, volts dc
Output 2
Form A mechanical (5 A) relay
Output 1
None, Switched dc/open collector,
Form C mechanical (5 A) relay
Off, Limit,
Alarm
Digital Output (or Input) 5 & 6
(optional) None, Switched dc
Off,
Alarm
Limit

Watlow PM LEGACY™Limit Controller •13 •Chapter 2 Install and Wire
2Chapter 2: Install & Wiring
INSTALLTION
1. For a PM3 Controller, make the panel cutout
using the measurements shown on page 6.
2. For a PM6 Controller, make the panel cutout
using the measurements shown on page 7.
3. Remove the green terminal connectors and
the mounting collar assembly.
4. Insert the controller into the panel cutout from
the front. See Figure 2. The controller shown
is a PM6 Controller.
5. Orient the collar base so the flat side faces
front and the screw openings are on the sides
(see Figure 2), then slide the base over the
back of the controller.
6. Slide the mounting bracket over the controller
with the screws aligned to the collar base.
See Figure 2. Push the bracket gently but
firmly until the hooks snap into the slots in
the case.
7. Tighten the two #6-19 x 1.5 in. screws with a
phillips screwdriver until the device is flush to
the panel (3 to 4 in-lbs torque). See Figure 3.
8. Reinstall the terminal connectors to their
original locations.
PM6 Controller
Mounting Screw
Mounting Panel
Figure 1: PM6 Installation
Figure 2: Slide Mounting Bracket
over Controller
Figure 3: Tighten the Mounting
Screws

Watlow PM LEGACY™Limit Controller •14 •Chapter 2 Install and Wire
Dimensions
1/32 DIN (PM3)
107.2mm
4.22in
10.2mm
0.40in
1.38in
35.2mm
Mounting Panel
2.10in
53.3mm
1.22in
30.9mm
1/32 DIN (PM3) Recommended Panel Spacing
21.6 mm
(0.85 in)
Minimum
44.96 to 45.47 mm
(1.77 to 1.79 inches)
Recommended panel spacing
panel thickness 1.53 to 9.52 mm
(0.060 to 0.375)
21.6 mm
(0.85 in)
Minimum
22.2 to 22.5 mm
(0.87 to0.89 inches)

Watlow PM LEGACY™Limit Controller •15 •Chapter 2 Install and Wire
10.16
0.40
107.18
4.22
1.38
35.16
Mounting Panel
2.10
53.34
2.10
53.34
1/16 DIN (PM6)
Recommended panel spacing
panel thickness 1.53 to 9.52 mm
(0.060 to 0.375)
44.96 to 45.47 mm
(1.77 to 1.79 inches)
44.96 to 45.47 mm
(1.77 to 1.79 inches)
21.6 mm
(0.85 in)
minimum
21.6 mm
(0.85 in)
minimum
1/16 DIN (PM6) Recommended Panel Spacing

Watlow PM LEGACY™Limit Controller •16 •Chapter 2 Install and Wire
Slot A Slot B Terminal Function Configuration
Inputs Universal, RTD and Thermistor Inputs
T1
S1
R1
S2 (RTD) or current +
S3 (RTD), thermocouple -, current -, volts -
or potentiometer wiper, thermistor
S1 (RTD), thermocouple + or volts +,
thermistor, potentiometer
Universal Sensor
Input 1: all configurations
Outputs Switched dc/open collector
1 2 3 4
X1
W1
Y1
X3
W3
Y3
Common (Any switched dc output can use
this common.)
dc- (open collector)
dc+
Output 1: PM6[L,M] _[C] J-AA _ _G_ _
Output 3: PM6[L,M] _ _J-AA[C] _ G_ _
Switched dc
W4
Y4
dc-
dc+
Output 4: PM6[L,M] _ _J-AA_ [C] G_ _
Universal Process
F3
G3
H3
voltage or current -
voltage +
current +
Output 3: PM6[L,M] _ _J-AA[F]_G_ _
Mechanical Relay 5 A, Form C
L1
K1
J1
L3
K3
J3
normally open
common
normally closed
Output 1: PM6[L,M] _ [E] J-AA_ _G_ _
Output 3: PM6[L,M] _ _J-AA[E] _G_ _
Mechanical Relay 5 A, Form A
L2
K2
L4
K4
normally open
common
Output 2: PM6[L,M] _ _[J] -AA_ _G_ _
Output 4: PM6[L,M] _ _J-AA_[J] G_ _
Solid-State Relay 0.5 A, Form A
L3
K3
L4
K4
normally open
common
Output 3: PM6[L,M] _ _J-AA[K] _G_ _
Output 4: PM6[L,M] _ _J-AA _ [K] G_ _
Communications Modbus RTU 232/485 Communications
CB
CA
CC
CB
CA
C5
C3
C2
CB
CA
CC
CB
CA
C5
C3
C2
Modbus RTU EIA-485 T+/R+
Modbus RTU EIA-485 T-/R-
Modbus RTU EIA-485 common
Modbus RTU EIA-485 T+/R+
Modbus RTU EIA-485 T-/R-
Modbus RTU EIA-232 common
Modbus RTU EIA-232 to DB9 pin 2
Modbus RTU EIA-232 to DB9 pin 3
Slot B:
PM6[L,M] _ _ J-[F,2] AAAG_ _
DeviceNet™Communications
Wiring

Watlow PM LEGACY™Limit Controller •17 •Chapter 2 Install and Wire
V+
CH
SH
CL
V-
V+
CH
SH
CL
V-
DeviceNet™ power
Positive side of DeviceNet™ bus
Shield interconnect
Negative side of DeviceNet™ bus
DeviceNet™ power return
DeviceNet™ Communications
Slot B:
PM6[L,M] _ _ J-[H,5] AAAG_ _
Slot A Slot B Terminal Function Configuration
Communications
(cont.)
EtherNet/IP™ and Modbus®TCP
E8
E7
E6
E5
E4
E3
E2
E1
E8
E7
E6
E5
E4
E3
E2
E1
EtherNet/IP™ and Modbus TCP unused
EtherNet/IP™ and Modbus TCP unused
EtherNet/IP™ and Modbus TCP receive -
EtherNet/IP™ and Modbus TCP unused
EtherNet/IP™ and Modbus TCP unused
EtherNet/IP™ and Modbus TCP receive +
EtherNet/IP™ and Modbus TCP transmit -
EtherNet/IP™ and Modbus TCP transmit +
Slot B:
PM6[L,M] _ _ J-[G,3] AAAG_ _
Profibus DP Communications
VP
B
A
DG
trB
B
A
trA
VP
B
A
DG
trB
B
A
trA
Voltage Potential
EIA-485 T+/R+
EIA-485 T-/R-
Digital ground (common)
Termination resistor B
EIA-485 T+/R+
EIA-485 T-/R-
Termination resistor A
Slot B:
PM6[L,M] _ _ J-[J,6] AAAG_ _
Terminal Definitions for Slot C
Slot C Terminal Function Configuration
Power
98
99
Power input: ac or dc+
Power input: ac or dc-
all
Standard Bus or Modbus EIA-485
CC
CA
CB
Standard Bus or Modbus RTU EIA-485 Common
Standard Bus or Modbus RTU EIA-485 T-/R-
Standard Bus or Modbus RTU EIA-485 T+/R+
Standard Bus or Modbus
PM6[L,M] _ _ J-[E,1] A_ _ G_ _
Standard Bus EIA-232/485
CF
CD
CE
Standard Bus EIA-485 common
Standard Bus EIA-485 T-/R-
Standard Bus EIA-485 T+/R+
PM __ _ _ _-[A, 2 or 3] _ _ _ AAA
2 - Digital I/O Points
B5
D6
D5
Digital input-output common
Digital input or output 6
Digital input or output 5
PM6[L,M] [2,4] _ J-[F,2] A_ _G_ _
Wiring (cont.)

Watlow PM LEGACY™Limit Controller •18 •Chapter 2 Install and Wire
Slot Orientation - Back View
1/32 DIN Horizontal PM3 1/16 DIN Vertical PM6
Note: Slot B above can also be configured with a communications card.
C
A
Power 485 Comms Dig I/O 5 & 6
Output 1Output 2 Input 1
C
Dig I/O 5 & 6 485 Comms Power
A
Output 2
Output 1 Input 1
B
Output 3 Output 4
PM Isolation Block
Digital Inputs & Outputs
5-6
Switched DC, Open Collector,
Process outputs
Analog Input 1
Communications Ports
Controller
Low Voltage Power Bus
Mechanical Relay,
Solid-State Relay
Outputs
Low-voltage Isolation: 42V peak
Safety Isolation: 2300V (ac)
Safety Isolation
No Isolation
Low-voltage
Isolation
No Isolation
Low-voltage
Isolation
Controller Power Supply
12 to 40V (dc)
20 to 28V (ac)
100 to 240V (ac)
Safety Isolation
Safety Isolation

Watlow PM LEGACY™Limit Controller •19 •Chapter 2 Install and Wire
Warning: ç
Use National Electric (NEC) or
other country-specific standard
wiring and safety practices when
wiring and connecting this con-
troller to a power source and to
electrical sensors or peripheral
devices. Failure to do so may
result in damage to equipment
and property, and/or injury or
loss of life.
Note:
Maximum wire size termination
and torque rating:
• 0.0507 to 3.30 mm2(30 to 12
AWG) single-wire termination
or two 1.31 mm2(16 AWG)
• 0.56 Nm (5.0 in-lb.) torque
Note:
Adjacent terminals may be la-
beled differently, depending on
the model number.
Note:
To prevent damage to the con-
troller, do not connect wires to
unused terminals.
Note:
Maintain electrical isolation
between analog input 1, digital
input-outputs, switched dc/open
collector outputs and process
outputs to prevent ground loops.
Low Power PM6[L,M] [3,4} _ J-_ A_ _G_ _
Power
power
power
98
99
CF
CD
CE
B5
D6
D5
Slot C
fuse
• Minimum/Maximum Ratings
• 12 to 40V (dc)
• 20 to 28V (ac) Semi Sig F47
• 47 to 63 Hz
• 10VA maximum power consumption (PM6)
High Power PM6[L,M] [1,2} _ J-_ A_ _G_ _
Power
power
power
98
99
CF
CD
CE
B5
D6
D5
Slot C
fuse
• Minimum/Maximum Ratings
• 85 to 264V ac)
• 100 to 240V (ac) Semi Sig F47
• 47 to 63 Hz
• 10VA maximum power consumption (PM6)
Digital Input 5 - 6 PM6[L,M] [2,4] _ J-_ A_ _G_ _
98
99
CF
CD
CE
B5
D6
D5
Slot C
DC Input
common
DC Input
Digital Input
• Update rate 10 Hz
• Dry contact or dc
voltage
DC Voltage
• Input not to exceed
36V dc) at 3mA
• Input active when >
3V (dc) @ 0.25mA
• Input inactive when <
2V
Dry Contact
• Input inactive when >
500Ω
• Input active when <
100Ω
• Maximum short circuit
13mA
Voltage Input
common
Vdc
D
_
B
_
Dry Contact
common
24 Vdc
B
_
_
D

Watlow PM LEGACY™Limit Controller •20 •Chapter 2 Install and Wire
Warning: ç
Use National Electric (NEC) or
other country-specific standard
wiring and safety practices when
wiring and connecting this con-
troller to a power source and to
electrical sensors or peripheral
devices. Failure to do so may
result in damage to equipment
and property, and/or injury or
loss of life.
Note:
Maximum wire size termination
and torque rating:
• 0.0507 to 3.30 mm2(30 to 12
AWG) single-wire termination
or two 1.31 mm2(16 AWG)
• 0.56 Nm (5.0 in-lb.) torque
Note:
Adjacent terminals may be la-
beled differently, depending on
the model number.
Note:
To prevent damage to the con-
troller, do not connect wires to
unused terminals.
Note:
Maintain electrical isolation
between analog input 1, digital
input-outputs, switched dc/open
collector outputs and process
outputs to prevent ground loops.
Input 1 Thermocouple PM6[L] _ _ J-_ _ _ _G_ _
-
+
L1
K1
J1
L2
K2
T1
S1
R1
Slot A • 2kΩ maximum source resistance
• >20MΩ input impedance
• 3µA open-sensor detection
• Thermocouples are polarity sensitive. The negative
lead (usually red) must be connected to S1
• To reduce errors, the extension wire for thermocou-
ples must be of the same alloy as the thermocouple
Input 1 RTD PM6[L] _ _ J-_ _ _ _G_ _
L1
K1
J1
L2
K2
T1
S1
R1
S1
S3
Slot A
2-wire
L1
K1
J1
L2
K2
T1
S1
R1
S1
S2
S3
Slot A
3-wire
• Platinum, 100 and 1kΩ @ 0°C
• Calibration to DIN curve (0.00385
Ω/Ω/°C)
• 20Ω total lead resistance
• RTD excitation current of 0.09mA
typical. Each ohm of lead resistance
may affect the reading by 0.03°C.
• For 3-wire RTDs, the S1 lead (usually
white) must be connected to R1 and/
or R2
• For best accuracy use a 3-wire RTD
to compensate for lead-length resis-
tance. All three lead wires must have
the same resistance
Input 1 Process PM6[L] _ _ J-_ _ _ _G_ _
-
+
L1
K1
J1
L2
K2
T1
S1
R1
Slot A
Volts
-
+T_
S_
Amperes
Slot A • 0 to 20mA @ 100Ω input impedance
• 0 to 10V (dc) @ 20kΩ input impedance
• 0 to 50mV (dc) @ 20kΩ input imped-
ance
• Scalable