Rockwell Automation T80001 Application Note Termination of Class 1 Division 2 Outputs - Manual

Trusted TM
AN-T80001
Issue 1 Sep 06 AN-T80001 1
Application Note
Termination of Class 1 Division 2 Outputs
Underwriters Laboratories Inc have confirmed that suitable non UL recognised termination resistors
may be used in Trusted systems, configured for Class 1 Division 2 applications.
The value of terminating resistors should be sized to provide the minimum load for the type of output
module; be capable of dissipating at least 2.5W and not have a surface temperature in excess of 50
degrees Centigrade above ambient temperature, when operating at maximum applied voltage.
For example, an 8451 requires a minimum load of 50mA, therefore a 680R +/- 5% resistor rated at
2.5W, mounted such that its maximum surface temperature does not exceed 50C above ambient,
when operating at a field voltage of 32Vdc, will comply with the requirements of Class 1 Division 2.
All termination resistors must be mechanically secured into terminal blocks or similar and need the
use of a tool to remove or disconnect them.
Issue Record
Issue
Number Date Revised by Technical
Check Authorised by Modification
1 Jan 07 Pete Stock Ray Brown Pete Stock Initial Issue