Emerson Rosemount OCX 8800, Instruction Manual

Page: 140 / 306

Section 7: Foundation
Fieldbus
April 2017
Instruction Manual
IM-106-880C, OI
11
4
Transducer Block
Simulate
7.10.5 Transducer Block Simulate
Setting PWA_SIMULATE to ON also allows simulating TB status and to check the correct
mapping onto the PWA’s FAILED_ACTIVE, MAINT_ACTIVE, and ADVISE_ACTIVE parameters.
7.10.6 Support Transducer Block Errors
Out of Service
• Set whenever the transducer block actual mode is OOS.
Input Failure
• Set whenever there is a communication error between the Fieldbus A2D card and the
OCX.
Simulation Active
• Set whenever the Fieldbus Simulate Switch is set to ON at the Fieldbus A2D card or
software simulate option is enabled.
Other Error
• Set whenever XD_ERROR is non-zero.
7.11 Analog Input (AI) Function Block
7.11.1 Introduction
The Hazardous Area OCX 8800 has four transducer block Input/Output channels ( Table 7-
21 ) for the AI function blocks. The status of channel values are defined in Table 7-23 .
The Analog Input (AI) function block ( Figure 7-5 ) processes field device measurements and
makes them available to other function blocks. The output value from the AI block is in
engineering units and contains a status indicating the quality of the measurement. The
measuring device may have several measurements or derived values available in different
channels. Use the channel number to define the variable that the AI block processes.
Figure 7-5 AI Function Block