Emerson Rosemount 925FGD User manual

Quick Start Guide
00825-0100-4925, Rev AC
April2023
Rosemount™ 925FGD Fixed Gas
Detector
Integrated Gas Detection

Safety information
WARNING
Explosions
Explosions could result in death or serious injury.
Installation of device in an explosive environment must be in accordance with
appropriate local, national, and international standards, codes, and practices.
Before connecting a hand-held communication device in an explosive atmosphere,
ensure the instruments are installed in accordance with Intrinsically Safe or non-
incendive field wiring practices.
Verify that the operating atmosphere of the transmitter is consistent with the
appropriate hazardous location certifications.
When connecting an external device to transmitter's discrete output in a hazardous area,
ensure that the external device is installed in accordance with Intrinsically Safe or non-
incendive field wiring practices.
WARNING
Physical access
Unauthorized personnel may potentially cause significant damage to and/or
misconfiguration of end users’ equipment. This could be intentional or unintentional and
needs to be protected against.
Physical security is an important part of any security program and fundamental to protecting
your system. Restrict physical access by unauthorized personnel to protect end users’ assets.
This is true for all systems used within the facility.
WARNING
Explosion hazard
Substitution of components may impair suitability for Class I, Division 1.
WARNING
AVERTISSEMENT - Risque d'explosion
La substitution de composants peut rendre ce materiel inacceptable pour les emplacements
de Classe I, Division 1.
CAUTION
Refer to the Product Certification section of this Quick Start Guide for documentation.
CAUTION
For safety reasons this equipment must be operated and serviced by qualified personnel
only. Read and understand the instruction manual completely before operating or servicing.
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CAUTION
ATTENTION
Pour des raisons de sécurité, cet equipment doit être utilisé, entretenu, et réparé
uniquement par un personnel qualifié. Étudier le manuel d'instructions en entier avant de
utiliser, entretenir, ou de réparer l'equipment.
NOTICE
Nuclear applications
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 nuclear-qualified products, contact an Emerson sales representative.
Contents
Device overview............................................................................................................................5
Installation.................................................................................................................................... 6
Configuration............................................................................................................................. 22
Sensor calibration...................................................................................................................... 24
Functional specifications...........................................................................................................28
Product certifications................................................................................................................ 30
Declaration of Conformity........................................................................................................ 34
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1 Device overview
The Rosemount 925FGD is a fixed gas detector compatible with the
Rosemount 625 Sensor Module.
The Rosemount 925FGD is a fully-assembled unit for only sensor-
direct-mount installations. For this configuration, you can order the
Rosemount 925FGD with or without the sensor module for instances
where sensor modules will be installed after the initial transmitter
installation.
The Rosemount 925FGD Transmitter consists of the transmitter
electronics, an LOI display, and infrared touch buttons contained
in an explosion-proof housing. The transmitter provides outputs,
including 4-20 mA analog signal, fault relay, alarm relays (2),
and HART® protocol. The transmitter is also equipped with status
indication LEDs.
All Rosemount 625 Sensors are smart sensors, meaning all
configuration, calibration, and gas sensing data is stored directly
on or generated directly from the sensor. This data is then
communicated to the Rosemount 925 Transmitter, which displays
information on the local operator interface (LOI) and generates
outputs for communication with site control systems.
For combustible hydrocarbon gas detection, the Rosemount 925FGD
incorporates the Rosemount 625ND Sensor Module. The Rosemount
625ND Sensor Module uses non-dispersive infrared technology
to measure combustible hydrocarbon gas using absorption
spectroscopy in the infrared sensor bands.
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2 Installation
2.1 Safety messages
Instructions in this section may require special precautions to ensure
the safety of personnel performing the operations.
WARNING
Follow installation guidelines
Failure to follow these installation guidelines could result in death or
serious injury.
Ensure that only qualified personnel perform the installation.
WARNING
If the equipment is used in a manner not specified by the
manufacturer, the protection provided by the equipment may be
impaired.
WARNING
Explosions
Before connecting a handheld communication device in an explosive
atmosphere, ensure that the instruments are installed in accordance
with Intrinsically Safe or non-incendive field wiring practices.
Verify that the operating atmosphere of the transmitter is consistent
with the appropriate hazardous locations certifications.
When connecting an external device to the Rosemount 925FGD's
discrete output in a hazardous area, ensure that the external device
is installed in accordance with Intrinsically Safe or non-incendive field
wiring practices.
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2.2 Mounting
The Rosemount 925FGD Gas Transmitter must be mounted with the
sensor directly attached to the transmitter as in Figure 2-1. You can
also mount the transmitter either on the surface or on a pole.
For the surface mounting with direct-mount sensors, refer to Figure
2-1.
Figure 2-1: Surface Mount with Direct-Mount Sensor
For pole mounting with direct-mount sensors, select the BP optional
model code, which includes the necessary pole mount bolts in the
box with the transmitter. Refer to Figure 2-2.
Figure 2-2: Pole Mount with Direct-Mount Sensor
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2.3 Wiring
2.3.1 Analog output, isolated supply, non-isolated supply, and
jumper configuration
The analog output may be powered from the main instrument power
supply or a separate, isolated power supply, in which case an isolated
wiring configuration is necessary.
An isolated loop uses 4-wires, 2 to power the device, and 2 for the
analog output. A non-isolated loop uses 3-wires, as the analog output
is tied into the power supply loop. Ensure the loop jumper is correctly
set for the wiring configuration you are using. See Figure 2-3
Figure 2-3: 925 Transmitter Terminal Block
2.3.2 Field wiring
The power to the transmitter is supplied over the signal wiring. Signal
wiring must be shielded, twisted pair. Do not run unshielded signal
wiring in conduit or open trays with power wiring or near heavy
electrical equipment because high voltage may be present on the
leads and may cause an electrical shock.
To meet EMC requirements, for the transmitter power wiring (V+
and COM) and signal wiring (mA+ and mA-) it is required to use
twisted shielded pair wires between the user power supply and the
925 transmitter. All flameproof entry devices, including plugs, must
be rated to a pressure greater than 2450 kPa (356 psi).
Seal all threads with an approved thread sealant, such as silicone or
PTFE tape (if required). When attaching the cover; tighten at least
one-third turn after the O-ring contacts the transmitter housing. The
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transmitter cover must be fully engaged to meet explosion proof
requirements
Note
Do not apply high voltage (e.g., AC line voltage) to the power or
sensor terminals, since high voltage can damage the unit
To wire the transmitter:
Table 2-1: Sensor terminals
Sensor terminals
Sensor wires Transmitter sensor board terminal designation
Red +Vdc (from transmitter)
Blue Signal A
White Signal B
Black Communication
Green Earth ground
Table 2-2: Transmitter power terminals
Transmitter power terminals
Transmitter terminal
designation
Function
V+ 18-30Vdc Power (+)
COM Power (-)
RST Remote reset
mA+ Current loop output
mA- Current loop output
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Figure 2-4: Direct mount wiring diagram
Note
Ground wire from 625 sensor must be connected to ground inside of
925 transmitter housing.
Isolated four-wire loop wiring
For a four-wire loop setup, ensure the loop jumper is set to the
ISOLATE position and that shielded, twisted pairs are used.
Figure 2-5: Isolated four-wire wiring diagram
A. Power supply (18-30 VDC)
B. 200 ≤ RL ≤ 800
C. Power/4-20 mA analog loop terminals
D. HART® modem
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Non-isolated three-wire loop wiring
For a four-wire loop setup, ensure the loop jumper is set to the NON
ISO position and that shielded, twisted pairs are used.
Figure 2-6: Non-isolated three-wire wiring diagram
A. Power supply (18-30 VDC)
B. 200 ≤ RL ≤ 800
C. Power/4-20 mA analog loop terminals
D. HART® modem
2.4 Verify operating atmosphere
Verify that the operating atmosphere of the transmitter and the
sensor is consistent with the appropriate hazardous locations
certifications.
Table 2-3: Temperature guidelines
Operating limit Transmitter storage
limit
Sensor storage
recommendation
-40°F (-40°C) to 140°F
(60°C)
-40°F (-40°C) to 185°F
(85°C)
34°F (1°C) to 45°F
(7°C)
Note
The electrochemical cells in the sensor have a limited shelf life. Store
sensor modules in a cool location that is not excessively humid or
dry.
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2.5 Local operator interface (LOI)
The Rosemount 925 Transmitter uses through-the-glass infrared (IR)
touch buttons to navigate the LOI display.
Figure 2-7 shows the location of the IR buttons on the left, right, and
bottom of the LOI.
Figure 2-7: Front view of LOI
For best results when activating the IR touch buttons, ensure that
your finger covers the complete surface of the glass above the
button.
The IR buttons have automatically adjusting sensitivity, meaning that
they will adjust to installation conditions, such as the cover being
removed.
2.5.1 Unlock local operator interface (LOI)
The Rosemount 925 Transmitter comes with a screen lock feature as
a default to inhibit accidental operation and potential environmental
stimulus that might activate the infrared (IR) touch buttons.
For added safety, you can enable a four-digit passcode instead of the
following standard unlock sequence. You can do this through the LOI
or via HART®.
For more information on this safety feature, refer to the Rosemount
925FGD Safety Manual.
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Procedure
1. Press any IR button to initiate the unlock sequence.
2. Press the check mark.
3. Press the up arrow.
4. Press the check mark.
5. Press the down arrow.
2.6 Power on and start-up
Once you have made all necessary wiring connections and applied
power, the transmitter will power on.
During this start-up process, the display will show a progress bar as
well as the firmware versions for all components of the Rosemount
925FGD system. The status indicator LEDs will cycle through all
colors: green, amber, and red.
Figure 2-8: Local operator interface (LOI) at start-up
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When a new sensor module is detected, either upon initial
installation or replacement of a sensor module, the configuration
settings are shown on the LOI. At this point, you have the option of
accepting configuration settings or selecting new settings.
Figure 2-9: New Sensor Detected Screen
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Following the configuration prompt, an additional prompt appears
stating that a field calibration is recommended. Refer to Calibration
options.
Figure 2-10: Field Calibration Recommended screen
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Unless one or more faults are present, the LOI will go to the Primary
Variable screen, displaying the gas type and current concentration
being measured by the sensor.
Figure 2-11: Primary Variable Screen Using Methane
Note
If the operator removes and reapplies power to the transmitter
without replacing the sensor module, and no faults are present upon
start-up, the display will go directly to the Primary Variable screen
following the Start-up screen.
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Note
If the 4-20 mA analog output has not been connected, a current
loop failure fault will be present after the other prompts have been
cleared. You can clear this fault either by terminating the 4-20 mA
output to the appropriate control system input or by placing a 250 Ω
resistor between the analog output terminals.
Figure 2-12: Current Loop Fault Screen
2.7 Outputs
The outputs from the Rosemount 925 Transmitter include the current
loop, HART signal, and relay outputs. The current loop and relay
outputs are updated every 200 milliseconds.
The 4-20 mA analog output is capable of both sink or source
configuration.
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The HART® protocol is accessible over the 4-20 mA analog wiring or
through the HART specific connection points found on the front of
the transmitter electronics, as shown in Figure 2-13.
Figure 2-13: HART Connection Points
Status indication LEDs are installed on the local operator interface
(LOI), located behind the check mark, up arrow, and down arrow
characters.
Table 2-4: Status Indication LEDs
Color Style Detector operation
mode
Green Alternating 3 seconds
On, 1 second Off
Normal mode
Amber Solid On Warning or Fault mode
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Table 2-4: Status Indication LEDs (continued)
Color Style Detector operation
mode
Red Solid On Gas concentrations
have reached Alarm 1
and/or Alarm 2 values.
Table 2-5: Device outputs status conditions
Status Current
loop
level
Fault
relay
output
Alarm 1
relay
output
Alarm 2
relay
output
Display Button
LED
color
Event
logged
Startup Less
than 0.5
mA
De-
energize
d
De-
energize
d
De-
energize
d
925 Red,
Amber,
Green,
Startup
sequen
ce
Yes
Sensor
initializat
ion
2.5 mA Fault Not
changed
Not
changed
Icons:
Sensor fault
icon
Fault
message
text:
"Sensor
Initializing"
Amber Yes
Signal
range
4.0 to
20.0 mA,
reflectin
g the gas
value
Not
changed
Not
changed
Not
changed
PV screen Green No
Hardwar
e failure
0 mA Fault Not
changed
Not
changed
Icons:
Sensor fault
icon
Fault
message
text:
"Transmitte
r electronic
failure"
Required
user action
text:
"Replace
module"
Amber Yes
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Table 2-5: Device outputs status conditions (continued)
Status Current
loop
level
Fault
relay
output
Alarm 1
relay
output
Alarm 2
relay
output
Display Button
LED
color
Event
logged
Diagnost
ic faults
2.0 mA Fault Not
changed
Not
changed
Icons:
Sensor fault
icon
Fault
message
text: "varies
base on
fault"
Required
user action
text: "varies
base on
fault"
Amber Yes
Diagnost
ic faults
with
active
alarm
If no
alarm is
active
then 2.5
mA, 4-20
mA if
alarm is
active
Fault Alarm
conditio
n
Alarm
conditio
n
Icons: Fault
icon
Fault
message
text: "varies
base on
fault"
Required
user action
text: "varies
base on
fault"
Red No
Sensor
calibrati
on
3.0 mA Not
changed
Not
changed
Not
changed
Message
text: "varies
based on
calibration
status"
Amber No
Under
range
2.0 mA Fault Not
changed
Not
changed
Icons:
Sensor fault
icon
Fault
message
text:
"Sensor
negative
drift"
Required
user action
text:
"Calibrate
sensor"
Amber Yes
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