Rosemount 752 User manual

www.rosemount.com
Reference Manual
00809-0100-4377, Rev BA
September 2010
Rosemount 752 Remote Indicator
with FOUNDATION™fieldbus protocol

Reference Manual
00809-0100-4377, Rev BA
September 2010 Rosemount 752
www.rosemount.com
Rosemount 752 Remote
Indicator with FOUNDATION™
fieldbus protocol
NOTICE
Read this manual before working with the product. For personal and system safety, and for
optimum product performance, make sure you thoroughly understand the contents before
installing, using, or maintaining this product.
Within the United States, Rosemount Inc. has two toll-free assistance numbers:
Customer Central
Technical support, quoting, and order-related questions.
1-800-999-9307 (7:00 am to 7:00 pm CST)
North American Response Center
Equipment service needs.
1-800-654-7768 (24 hours—includes Canada)
Outside of the United States, contact your local Emerson Process Management
representative.
The products described in this document are NOT designed for nuclear-qualified
applications. Using non-nuclear qualified products in applications that require
nuclear-qualified hardware or products may cause inaccurate readings.
For information on Rosemount nuclear-qualified products, contact your local Emerson
Process Management Sales Representative.

Reference Manual
00809-0100-4377, Rev BA
September 2010 Rosemount 752
www.rosemount.com
Table of Contents
SECTION 1
Introduction Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Using This Manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Service Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Device Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Node Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Foundation fieldbus function blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
SECTION 2
Configuration Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Safety Messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Installation of the Rosemount 752. . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Set Switches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Connect Wiring and Power Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
General Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Tagging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Hazardous Locations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Grounding the Indicator Case. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
General Block Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Link Active Scheduler. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Block Instantiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Capabilities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Resource Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
FEATURES and FEATURES_SEL . . . . . . . . . . . . . . . . . . . . . . . . 2-9
MAX_NOTIFY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
PlantWeb™Alarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
LCD Transducer Block. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13
Custom Meter Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14
SECTION 3
Operation and
Maintenance
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Safety Messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Resource Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Master Reset Method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Software Upgrade in the Field. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
SECTION 4
Troubleshooting Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Safety Messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Troubleshooting Guides. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Resource Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
LCD Transducer block. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6

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APPENDIX A
Reference Information Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1
Functional Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1
Performance Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1
Physical Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1
Dimensional Drawings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-2
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-3
APPENDIX B
Product Certificates Approved Manufacturing Locations. . . . . . . . . . . . . . . . . . . . . . . . . . .B-1
European Directive Information . . . . . . . . . . . . . . . . . . . . . . . . . . .B-1
Hazardous Locations Certifications. . . . . . . . . . . . . . . . . . . . . . . . . . .B-1
North American Certifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . .B-1
Canadian Standards Association (CSA). . . . . . . . . . . . . . . . . . . . .B-2
European Certifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B-2
IECEx Certifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B-4
Approval Drawings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B-5
APPENDIX C
Block Information Resource Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C-1
Parameters and Descriptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . .C-1
LCD Transducer Block. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C-7

Reference Manual
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September 2010 Rosemount 752
www.rosemount.com
Section 1 Introduction
OVERVIEW This manual was developed with the assumption that the user will have a
basic understanding of FOUNDATION Fieldbus concepts and wiring practices.
Information is available at www.plantweb.emersonprocess.com/university or
check with your system integrator about resources for your specific host
system.
USING THIS MANUAL The sections in this manual provide information on configuring,
troubleshooting, operating and maintaining the Rosemount 752 Remote
Indicator with FOUNDATION fieldbus protocol.
The sections in this manual are organized as follows:
•Section 2: Configuration provides instruction on configuration of the
Rosemount 752 Remote Indicator with FOUNDATION fieldbus protocol.
Information on software functions, configuration parameters, and other
variables are also included.
•Section 3: Operation and Maintenance contains operation and
maintenance techniques.
•Section 4: Troubleshooting provides troubleshooting techniques for
the most common operating problems.
•Appendix A: Reference Information supplies reference and
specification data, as well as ordering information.
•Appendix B: Product Certificates contains intrinsic safety approval
information, European ATEX directive information, and approval.
•Appendix C: Block Information supplies reference block information
such as parameter tables.

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Service Support To expedite the return process outside of the United States, contact the
nearest Rosemount representative.
Within the United States, call the Rosemount National Response Center using
the 1-800-654-RSMT (7768) toll-free number. This center, available 24 hours
a day, will assist you with any needed information or materials.
The center will ask for product model and serial numbers, and will provide a
Return Material Authorization (RMA) number. The center will also ask for the
process material to which the product was last exposed.
Rosemount National Response Center representatives will explain the
additional information and procedures necessary to return goods exposed to
hazardous substances.
DEVICE DESCRIPTION Before configuring the device, ensure the host has the appropriate Device
Description file revision for this device. The device descriptor can be found on
www.rosemount.com.
NODE ADDRESS The indicator is shipped at a temporary (248) address. This will enable
FOUNDATION fieldbus host systems to automatically recognize the device and
move it to a permanent address.
Individuals who handle products exposed to a hazardous substance can avoid injury if
they are informed of and understand the hazard. If the product being returned was
exposed to a hazardous substance as defined by OSHA, a copy of the required Material
Safety Data Sheet (MSDS) for each hazardous substance identified must be included
with the returned goods.

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Rosemount 752
FOUNDATION FIELDBUS
FUNCTION BLOCKS For reference information on the LCD Transducer and Advanced Diagnostics
Transducer blocks refer to “Foundation Fieldbus Block Information” on
page A-1. Reference information on the ISEL, INT, ARTH, SGCR and PID
blocks can be found in the Function Block manual document number
00809-0100-4783.
Resource Block (1000)
The Resource block contains diagnostic, hardware and electronics
information. There are no linkable inputs or outputs to the Resource Block.
LCD Transducer Block (1100)
The LCD Transducer Block is used to configure the LCD meter.
PID Block (1200)
The PID Function Block combines all of the necessary logic to perform
proportional/integral/derivative (PID) control. The block supports mode
control, signal scaling and limiting, feed forward control, override tracking,
alarm limit detection, and signal status propagation.
The block supports two forms of the PID equation: Standard and Series. You
can choose the appropriate equation using the MATHFORM parameter. The
Standard ISA PID equation is the default selection.
Input Selector Block (1300)
The Input Selector (ISEL) Function Block can be used to select the first good,
Hot Backup, maximum, minimum, or average of as many as eight input
values and place it at the output. The block supports signal status
propagation.
Signal Characterizer Block (1400)
The Signal Characterizer (SGCR) Function Block characterizes or
approximates any function that defines an input/output relationship. The
function is defined by configuring as many as twenty X,Y coordinates. The
block interpolates an output value for a given input value using the curve
defined by the configured coordinates. Two separate analog input signals can
be processed simultaneously to give two corresponding separate output
values using the same defined curve.
Arithmetic Block (1500)
The Arithmetic (ARTH) Function Block provides the ability to configure a
range extension function for a primary input. It can also be used to compute
nine different arithmetic functions.
Integrator Block (1600)
The Integrator (INT) Function Block integrates one or two variables over time.
The block compares the integrated or accumulated value to pre-trip and trip
limits and generates discrete output signals when the limits are reached.

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Reference Manual
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September 2010 Rosemount 752
www.rosemount.com
Section 2 Configuration
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .page 2-1
Safety Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .page 2-1
General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . .page 2-5
Connect Wiring and Power Up . . . . . . . . . . . . . . . . . . . . .page 2-3
Hazardous Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . .page 2-6
General Block Information . . . . . . . . . . . . . . . . . . . . . . . . .page 2-7
Resource Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .page 2-9
LCD Transducer Block . . . . . . . . . . . . . . . . . . . . . . . . . . . .page 2-13
OVERVIEW This section covers basic operation, software functionality, and basic
configuration procedures for the Rosemount 752 Remote Indicator with
FOUNDATION fieldbus protocol. This section is organized by block information.
For detailed information about the function blocks used in the Rosemount 752
Remote Indicator, refer to “Block Information” on page C-1 and the
Foundation fieldbus Block manual (00809-0100-4783).
SAFETY MESSAGES Procedures and instructions in this section may require special precautions to
ensure the safety of the personnel performing the operations. Information that
raises potential safety issues is indicated by a warning symbol ( ). Refer to
the following safety messages before performing an operation preceded by
this symbol.
Warnings
Explosions can result in death or serious injury.
• Do not remove the indicator covers in explosive environments when the circuit
is live.
• Indicator covers must be fully engaged to meet explosion proof requirements.
• Before connecting a configuration tool in an explosive atmosphere, make sure
the instruments in the loop are installed in accordance with intrinsically safe or
nonincendive field wiring practices.
Electrical shock can result in death or serious injury.
• Avoid contact with the leads and terminals. High voltage that may be present
on leads can cause electrical shock.

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INSTALLATION OF THE
ROSEMOUNT 752
Set Switches Security (Write Protect)
Changes can be prevented to the indicator configuration data with the write
protection PlantWeb housing switches. Security is controlled by the security
(write protect) switch/jumper located on the interface assembly or terminal
block. Position the switch/jumper in the “ON” position to prevent accidental or
deliberate change of configuration data.
If the indicator write protection switch/jumper is in the “ON” position, the
indicator will not accept any “writes” to its memory. Configuration changes
cannot take place when the indicator security is on.
To reposition the switches/jumpers, follow the procedure described
below. (Simulate = fieldbus protocol)
1. Set the loop to manual and remove power.
2. Remove the electronics compartment cover, opposite the field terminal
side on the PlantWeb housing. Do not remove the indicator covers in
explosive atmospheres when the circuit is live.
3. Slide the security and simulate switches into the preferred position by
using a small screwdriver.
Re-install the indicator cover. Indicator covers must be fully engaged to meet
explosion-proof requirements.
Figure 2-1. PlantWeb Housing
Switches
Security Alarm/Simulate

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Rosemount 752
Connect Wiring and
Power Up Wiring for fieldbus protocol
1. Remove the housing cover on terminal compartment side. Do not
remove the cover in explosive atmospheres when the circuit is live.
Signal wiring supplies all power to the indicator.
2. Connect the power leads to the terminals marked “FIELDBUS WIRING”
as shown in Figure 2-2. The power terminals are not polarity sensitive.
3. Plug and seal unused conduit connections on the indicator housing to
avoid moisture accumulation in the terminal side. If you do not seal
unused connections, mount the indicator with the electrical housing
positioned downward for drainage. Install wiring with a drip loop. Arrange
the drip loop so the bottom is lower than the conduit connections and the
indicator housing.
NOTE
Do not apply high voltage (e.g. ac line voltage) to the indicator terminals.
Abnormally high voltage can damage the unit. (Indicator power terminals are
rated to 32 V dc).
Figure 2-2. Fieldbus terminal
block
Electrical Considerations
Proper electrical installation is necessary to prevent errors due to improper
grounding and electrical noise. Shielded, twisted pair cable should be
used for best results in electrically noisy environments. Cable Type A is
recommended by FOUNDATION®fieldbus.
Power Supply
The indicator requires between 9 and 32 V dc (9 and 15 V dc for FISCO) to
operate and provide complete functionality. The dc power supply should
provide power with less than 2% ripple.
Power Conditioner
A fieldbus segment requires a power conditioner to isolate the power
supply filter and decouple the segment from other segments attached to
the same power supply.
Grounding
Signal wiring of the fieldbus segment can not be grounded. Grounding out
one of the signal wires will shut down the entire fieldbus segment.
See “Safety Messages” on page 2-1 for complete warning information.

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Shield Wire Ground
To protect the fieldbus segment from noise, grounding techniques for
shield wire usually require a single grounding point for shield wire to avoid
creating a ground loop. The ground point is typically at the power supply.
Figure 2-3. Fieldbus indicator
field wiring
Surges/Transients
The indicator will withstand electrical transients of the energy level usually
encountered in static discharges or induced switching transients. However,
high-energy transients, such as those induced in wiring from nearby
lightning strikes, can damage the indicator.
Optional Transient Protection Terminal Block
The transient protection terminal block can be ordered as an installed
option (Option Code T1 in the indicator model number) or as a spare part.
The spare part number is 03151-4134-0002. The lightning bolt symbol
shown identifies it as a transient protection terminal block.
NOTE
The fieldbus physical layer specification requires indicator communication
during extreme operating conditions of 250 V rms common mode signal. The
transient terminal block was designed to limit common mode voltages to 90 V
and cannot be used in these extreme operating conditions.
Power
Supply
FOUNDATION
fieldbus
Configuration
Tool
Terminators
Integrated Power
Conditioner
and Filter
(Trunk)
(Spur)
(Spur)
(The power supply, filter, first
terminator, and configuration tool are
typically located in the control room.)
Signal
Wiring
Fieldbus
Segment
6234 ft (1900 m) max
(depending upon cable
characteristics)
*Intrinsically safe installations may allow fewer devices per I.S. barrier due to current limitations.
fieldbus
devices on
segment

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Rosemount 752
GENERAL
CONSIDERATIONS
Tagging Commissioning (Paper) Tag on a fieldbus segment
When commissioning more than one device on a fieldbus segment, it can be
difficult to identify which device is at a particular location. A removable tag
provided with the indicator can aid in this process by linking the Device ID and
a physical location. The Device ID is a unique code that identifies a particular
device in the absence of a device tag. The device tag is used by the customer
as an operational identification for the device and is usually defined by the
Piping and Instrumentation Diagram (P & ID).
The installer should note the physical location in both places on the
removable commissioning tag and tear off the bottom portion. This should be
done for each device on the segment. The bottom portion of the tags can be
used for commissioning the segment in the control system, providing a direct
link between the Device ID and the tag location.
COMMISSIONING TAG
Device ID:
00XXXXXXXX010001440-121698091725
PD Tag:
PT- 101
Revision: 7.2
Support files available at
www.rosemount.com
Revision: 7.2
Support files available at
www.rosemount.com
Device Serial Number:
XXXXXXXXXX
Device ID:
00XXXXX010001440-121698091725
PD Tag:
PT- 101
Tear Here

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HAZARDOUS
LOCATIONS The 752 Remote Indicator has explosion-proof housing and circuitry suitable
for intrinsically safe and non-incendive operation. Individual indicators are
clearly marked with a tag indicating the certifications they carry. See
Appendix B: Product Certificates for installation drawings.
NOTE
Once a device labeled with multiple approvals is installed, it should not be
reinstalled using any other approval type(s). Permanently mark the
certification label to distinguish the installed approval type from unused
approval types.
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 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.

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Rosemount 752
GENERAL BLOCK
INFORMATION
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.
MAN
In this mode, variables that are passed out of the block can be manually
set for testing or override purposes.
Other Types of Modes
Other types of modes are Cas, RCas, ROut, IMan and LO. Some of these
may be supported by different function blocks in the 752. For more
information, see the Function Block manual, document 00809-0100-4783.
NOTE
When an upstream block is set to OOS, this will impact the output status of all
downstream blocks. The figure below depicts the hierarchy of blocks:
Resource
Block
Transducer
Block
Analog Input
(AI Block)
Other
function
blocks

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Link Active Scheduler The 752 can be designated to act as the backup Link Active Scheduler (LAS)
in the event that the LAS is disconnected from the segment. As the backup
LAS, the 752 will take over the management of communications until the host
is restored.
The host system may provide a configuration tool specifically designed to
designate a particular device as a backup LAS. Otherwise, this can be
configured manually as follows:
1. Access the Management Information Base (MIB) for the 752.
2. To activate the LAS capability, write 0x02 to the
BOOT_OPERAT_FUNCTIONAL_CLASS object (Index 605). To
deactivate, write 0x01.
3. Restart the processor.
Block Instantiation Rosemount devices are pre-configured with function blocks at the factory, the
default permanent configuration for the Rosemount 752 is listed below. The
Rosemount 752 can have up to nine additional instantiated function blocks.
• 1 Proportional/Integral/Derivative Block (tag name PID_1600)
• 1 Input Selector Block (tag name ISEL_1700)
• 1 Signal Characterizer Block (tag name CHAR_1800)
• 1 Arithmetic Block (tag name ARITH_1900)
• 1 Integrator Block (tag name INTEG_2000)
The Rosemount 752 supports the use of Function Block Instantiation. When a
device supports block instantiation, the number of blocks and block types can
be defined to match specific application needs.The number of blocks that can
be instantiated is only limited by the amount of memory within the device and
the block types that are supported by the device. Instantiation does not apply
to standard device blocks like the Resource and LCD Transducer Block.
By reading the parameter “FREE_SPACE” in the Resource block you can
determine how many blocks you can instantiate. Each block that you
instantiate takes up 4.5573% of the “FREE_SPACE”.
Block instantiation isdone by the host control system or configuration tool, but
not all hosts are required to implement this functionality. Please refer to your
specific host or configuration tool manual for more information.

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Rosemount 752
Capabilities Virtual Communication Relationship (VCRs)
There are a total of 20 VCRs. One is permanent and 19 are fully configurable
by the host system. Thirty link objects are available.
Host timer recommendations
T1 = 96000
T2 = 1920000
T3 = 480000
Block Execution times
PID = 10 ms
Arithmetic = 10 ms
Input Selection = 10 ms
Signal Characterizer = 10 ms
Integrator = 10 ms
RESOURCE BLOCK
FEATURES and
FEATURES_SEL The parameters FEATURES and FEATURE_SEL determine optional
behavior of the Rosemount 752.
FEATURES
The FEATURES parameter is read only and defines which features are
supported by the Rosemount 752. Below is a list of the FEATURES the 752
supports.
UNICODE
All configurable string variables in the Rosemount 752, except tag names, are
octet strings. Either ASCII or Unicode may be used. If the configuration device
is generating Unicode octet strings, you must set the Unicode option bit.
REPORTS
The Rosemount 752 supports alert reports. The Reports option bit must be
set in the features bit string to use this feature. If it is not set, the host must
poll for alerts.
Network Parameter Value
Slot Time 6
Maximum Response Delay 4
Maximum Inactivity to Claim LAS Delay 60
Minimum Inter DLPDU Delay 7
Time Sync class 4 (1ms)
Maximum Scheduling Overhead 21
Per CLPDU PhL Overhead 4
Maximum Inter-channel Signal Skew 0
Required Number of Post-transmission-gab-ext Units 0
Required Number of Preamble-extension Units 1

Reference Manual
00809-0100-4377, Rev BA
September 2010
Rosemount 752
2-10
SOFT W LOCK and HARD W LOCK
Inputs to the security and write lock functions include the hardware security
switch, the hardware and software write lock bits of the FEATURE_SEL
parameter, the WRITE_LOCK parameter, and the DEFINE_WRITE_LOCK
parameter.
The WRITE_LOCK parameter prevents modification of parameters within the
device except to clear the WRITE_LOCK parameter. During this time, the
block will function normally updating inputs and outputs and executing
algorithms. When the WRITE_LOCK condition is cleared, a WRITE_ALM
alert is generated with a priority that corresponds to the WRITE_PRI
parameter.
The FEATURE_SEL parameter enables the user to select a hardware or
software write lock or no write lock capability. To enable the hardware security
function, enable the HW_SEL bit in the FEATURE_SEL parameter. When this
bit has been enabled the WRITE_LOCK parameter becomes read only and
will reflect the state of the hardware switch. In order to enable the software
write lock, the SW_SEL bit must be set in the FEATURE_SEL parameter.
Once this bit is set, the WRITE_LOCK parameter may be set to “Locked” or
“Not Locked.” Once the WRITE_LOCK parameter is set to “Locked” by either
the software or the hardware lock, all user requested writes as determined by
the DEFINE_WRITE_LOCK parameter shall be rejected.
The DEFINE_WRITE_LOCK parameter allows the user to configure whether
the write lock functions (both software and hardware) will control writing to all
blocks, or only to the resource and transducer blocks. Internally updated data
such as process variables and diagnostics will not be restricted by the
security switch.
The following table displays all possible configurations of the WRITE_LOCK
parameter.
FEATURES_SEL
FEATURES_SEL is used to turn on any of the supported features. The default
setting of the Rosemount 752 does not select any of these features. Choose
one of the supported features if any.
MAX_NOTIFY The MAX_NOTIFY parameter value is the maximum number of alert reports
that the resource can have sent without getting a confirmation, corresponding
to the amount of buffer space available for alert messages. The number can
be set lower, to control alert flooding, by adjusting the LIM_NOTIFY
parameter value. If LIM_NOTIFY is set to zero, then no alerts are reported.
FEATURE_SEL
HW_SEL bit FEATURE_SEL SW_SEL bit SECURITY SWITCH WRITE_LOCK WRITE_LOCK Read/Write DEFINE_WRITE_LOCK Write access to blocks
0 (off) 0 (off) NA 1 (unlocked) Read only NA All
0 (off) 1 (on) NA 1 (unlocked) Read/Write NA All
0 (off) 1 (on) NA 2 (locked) Read/Write Physical Function
Blocks only
0 (off) 1 (on) NA 2 (locked) Read/Write Everything None
1 (on) 0 (off)(1) 0 (unlocked) 1 (unlocked) Read only NA All
1 (on) 0 (off) 1 (locked) 2 (locked) Read only Physical Function
Blocks only
1 (on) 0 (off) 1 (locked) 2 (locked) Read only Everything None
(1) The hardware and software write lock select bits are mutually exclusive and the hardware select has the highest priority. When the HW_SEL bit if set to 1
(on), the SW_SEL bit is automatically set to 0 (off) and is read only.