Emerson Rosemount 751 User manual

Quick Start Guide
00825-0100-4378, Rev AE
February 2019
Rosemount™ 751 Field Signal Indicator

About this guide
This guide provides basic guidelines for Rosemount 751 Remote Indicator. It does not provide
instructions for configuration, diagnostics, maintenance, service, troubleshooting, Explosionproof,
Flameproof, or intrinsically safe (I.S.) installations. Refer to the Rosemount 751 Reference Manual for
more instruction. This manual is also available electronically on Emerson.com/Rosemount.
WARNING
Explosions could result in death or serious injury.
•Installation of this indicator in an explosive environment must be in accordance with the
appropriate local, national, and international standards, codes, and practices. Review the Product
Certifications section for any restrictions associated with a safe installation.
•In an explosion-proof/flameproof installation, do not remove the indicator cover when power is
applied to the unit.
Electrical shock could cause death or serious injury.
•Avoid contact with the leads and terminals. High voltage that may be present on leads can cause
electrical shock.
Contents
Installation.....................................................3
Configuration.................................................9
Product Certification....................................12
Declaration of Conformity............................18
China RoHS.................................................. 21
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2 Rosemount 751

1 Installation
1.1 Assembly
The Rosemount 751 Field Signal Indicator is comprised of the components
shown in Figure 1-1. The housing may contain an analog or LCD display meter.
Both meters are independent of component parts and are completely
interchangeable. Both meters plug into the terminal screws on the housing,
as shown in Figure 1-1.
The meter subassembly contains the components shown in Figure 1-2.
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Figure 1-1: Rosemount 751 Exploded View
A
BC
DE
FG
H
I
J
K
L
M
N
A. Terminal screws
B. Housing O-ring
C. Field Wiring Terminals
D. Loop Protection Diode
E. Tapped Mounting Boss
F. Optional Mounting Bracket
G. Mounting Bolt with Washer
H. U-Bolt for 2-in. Pipe
I. Housing
J. Optional ¾ to ½-in. Conduit Reducing bushing (if required)
K. Meter
L. Bushing
M. Foam Spacer
N. Housing Cover
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Figure 1-2: Meter Exploded View
A
B
C
D
K
J
I
H
G
F
E
A. Retaining Straps
B. Mounting Screw into Housing
C. Washer for Retaining Strap
D. Mounting Screws into Mounting Plate
E. Terminal Screws (2)
F. Mounting Plate
G. Spacer Plate
H. LCD Display
I. Bushing
J. Foam Spacer
K. Configuration Buttons
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1.2 Wiring diagrams
Use the following wiring diagrams to wire the Rosemount 751 Field Signal
Indicator, in series or in parallel, with Rosemount transmitters. Use shielded
cable for best results in electrically noisy environments.
It is recommended that the Rosemount 751 indicator be wired in a series
configuration when the 4-20 mA transmitter does not contain a test terminal.
The Rosemount 751 is designed so the analog or LCD display meter can be
removed from the housing without impacting the integrity of the 4-20 mA
loop. Removal of the entire Rosemount 751 device from the series
configuration will disrupt the loop.
Figure 1-3: Rosemount 751 Series Wiring Diagrams
+−
A B
C
3144P
+
−
751
+−
A B
C
2051
+−T
751
+
−
4–20 mA dc Input Signal for Rosemount
3144P
4–20 dc Input Signal for Rosemount 2051
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+−
A B
C
751
+
−
3051C
+−T
+−
AB
C
751
+
−
3051S + −T
4–20 mA dc Input Signal for Rosemount
3051C
4–20 dc Input Signal for Rosemount
3051S
A. Power supply
B. Load resistor
C. Optional ground
It is recommended that the Rosemount 751 indicator be wired in a parallel
configuration when the 4-20 mA transmitter includes a test terminal.
Utilization of the test terminal is required in a parallel configuration.
Connecting the 751 indicator across the positive and negative terminals of
the 4-20 mA transmitter could impact the loop.
A parallel configuration will allow the removal of the 751 indicator without
affecting the integrity of the 4-20 mA loop. Additionally, spare 751 indicators
can be added without disrupting the loop.
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Figure 1-4: Rosemount 751 Parallel Wiring Diagrams
A
+-
B
C
-
+
T3144P
-+
751
A
+ -
BC
+-T2051
751
- +
4–20 mA dc Input Signal for Rosemount
3144P
4–20 dc Input Signal for Rosemount 2051
A
+-
BC
+-T
3051C
751
-+
+-
A
BC
+-T 3051S
- +
751
4–20 mA dc Input Signal for Rosemount
3051C
4–20 dc Input Signal for Rosemount
3051S
A. Power supply
B. Load resistor
C. Optional ground
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2 Configuration
2.1 LCD display configuration
The 20-segment bar graph is factory calibrated and represents 4–20 mA
directly, but the end points of the LCD display are user-definable. The meter
requires a current between 4 and 20 mA in order to be scaled, but the actual
value of the current is not significant.
2.1.1 Remove the cover
WARNING
Explosions could result in death or serious injury.Do not remove the
transmitter cover in explosive atmospheres when the circuit is live.
Procedure
Unscrew and remove the transparent housing cover from the LCD display
body.
2.1.2 Position the decimal point and select the meter function
Procedure
1. Press the left and right configuration buttons simultaneously and
release them immediately.
2. To move the decimal point to the desired location, press the left
configuration button.
Note
The decimal point wraps around.
3. To scroll through the mode options, press the right configuration
button repeatedly until the meter displays the desired mode (SeeTable
2-1).
Note
The LCD display time-out is approximately 16 seconds. If you do not
press the configuration buttons within 16 seconds, the indicator will
revert to reading the current signal.
Table 2-1: LCD Display Mode Options
Options Relationship between Input Signal
and Digital Display
L in Linear
LinF Linear with five-second filter
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Table 2-1: LCD Display Mode Options (continued)
Options Relationship between Input Signal
and Digital Display
Srt Square root
SrtF Square root with five-second filter
Square root function only relates to the digital display. The bar graph output
remains
linear with the current signal.
Square root response
The digital display will be proportional to the square root of the input current
where 4 mA = 0 and 20 mA = 1.0, scaled per the calibration procedure. The
transition point from linear to square root is at 25 percent of full scale flow.
Filter response operates upon “present input” and “input received in the
previous five
second interval” in the following manner:
Display = (0.75 previous input) + (0.25 present input)
This relationship is maintained provided that the previous reading minus the
present
reading is less than 25 percent of full scale.
2.1.3 Store the information
Procedure
Press both configuration buttons simultaneously for two seconds.
Note
The meter displays “- -” for approximately 7.5 seconds while the information
is being stored.
2.1.4 Set the display equivalent to a 4 mA signal
Procedure
1. Press the left configuration button for two seconds.
2. To decrease the display numbers, press the left configuration button.
To increase the numbers, press the right configuration button. Set the
numbers between –999 and 1000.
3. To store the information, simultaneously press both configuration
buttons for two seconds.
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