Emerson Rosemount 752 FOUNDATION, Справочное руководство

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8
Reference Manual
00809-0100-4377, Rev CA
Configuration
January 2018
Configuration
2.5.1 Grounding the indicator case
Always ground the indicator case in accordance with national and local electrical codes. The most
effective indicator case grounding method is a direct connection to earth ground with minimal
impedance. Methods for grounding the indicator case include:

Internal ground connection
: The internal ground connection screw is inside the terminal side of the
electronics housing. The screw is identified by a ground symbol ( ), and is standard on the
Rosemount 752 Remote Indicators.

External ground assembly
: Ground screw is located at the bottom of the mounting bracket.
Note
Grounding the indicator case using the threaded conduit connection may not provide a sufficient
ground. The transient protection terminal block (Option Code T1) will not provide transient protection
unless the indicator case is properly grounded. Use the above guidelines to ground the indicator case. Do
not run transient protection ground wire with signal wiring; the ground wire may carry excessive current
if a lightning strike occurs.
2.6 General block information
2.6.1 Modes
The Resource, Transducer, and all function blocks in the device have modes of operation. These modes
govern the operation of the block. Every block supports both automatic (AUTO) and out of service (OOS)
modes. Other modes may also be supported.
Changing modes
To change the operating mode, set the MODE_BLK.TARGET to the desired mode. After a short delay, the
parameter MODE_BLOCK.ACTUAL should reflect the mode change if the block is operating properly.
Permitted modes
It is possible to prevent unauthorized changes to the operating mode of a block. To do this, configure
MODE_BLOCK.PERMITTED to allow only the desired operating modes. It is recommended to always
select OOS as one of the permitted modes.
Types of modes
For the procedures described in this manual, it will be helpful to understand the following modes:
AUTO
The functions performed by the block will execute. If the block has any outputs, these will continue to
update. This is typically the normal operating mode.
Out of service (OOS)
The functions performed by the block will not execute. If the block has any outputs, these will typically
not update and the status of any values passed to downstream blocks will be “BAD”. To make some
changes to the configuration of the block, change the mode of the block to OOS. When the changes are
complete, change the mode back to AUTO.