PPC-2000 User’s Guide
Chapter 2: Hardware Installation
Doc.# 30002-00 Rev 2.3
Watlow Anafaze
73
Using Snubbers for Relay Outputs
Relay contacts can arc and/or generate EMI. Over time, arcing
will shorten the life of relay contacts and EMI can disrupt
system functions. Use snubbers—a resistor and capacitor in
series— to protect against EMI and lengthen relay life.
The capacitor should be non-polarized and may be metallized
polyester film or metallized polypropylene and the voltage
rating must be 600Vdc/250Vac. The resistor may be carbon
composition or carbon film. It should be 0.5 or 1 watt with 5%
tolerance. Use 1 watt if the contacts are used in a rapid cycling
application.
The following values are acceptable for most applications using
the PPC-2061 and PPC-2062 relay output modules:
•
Resistor: 120
Ω
•
Capacitor: 0.47
µ
F
Install the snubber across the contacts or the load. Generally,
it performs more reliably across the contacts.
Figure 2.61 Snubber Connections
H
120/240Vac
C
R
Preferred Method
Contacts
Load
Alternative
Method
N
Summary of Contents for Anafaze PPC-2000
Page 2: ......
Page 14: ...Table of Contents PPC 2000 User s Guide viii Watlow Anafaze Doc 30002 00 Rev 2 3...
Page 24: ...List of Tables PPC User s Guide xviii Watlow Anafaze Doc 30002 00 Rev 2 3...
Page 36: ...Chapter 1 Overview PPC 2000 User s Guide 12 Watlow Anafaze Doc 30002 00 Rev 2 3...
Page 112: ...Chapter 2 Hardware Installation PPC 2000 User s Guide 88 Watlow Anafaze Doc 30002 00 Rev 2 3...
Page 184: ...Chapter 4 Troubleshooting PPC 2000 User s Guide 158 Watlow Anafaze Doc 30002 00 Rev 2 3...
Page 296: ...Chapter 7 Specifications PPC 2000 User s Guide 268 Watlow Anafaze Doc 30002 00 Rev 2 3...
Page 310: ...Appendix A Modbus Protocol PPC 2000 User s Guide 282 Watlow Anafaze Doc 30002 00 Rev 2 3...
Page 311: ...Doc 30002 00 Rev 2 3 Watlow Anafaze 283 B Appendix B Declaration of Conformity...
Page 319: ...PPC 2000 User s Guide Glossary Doc 30002 00 Rev 2 3 Watlow Anafaze 291...
Page 320: ...Glossary PPC 2000 User s Guide 292 Watlow Anafaze Doc 30002 00 Rev 2 3...