EMERSON Rosemount 975 Flame Detectors User Guide

: June 3, 2024
: Emerson

Table of Contents

Rosemount 975 series
Certified product identification of the device
Applied standards
Safety parameters
Guidelines for configuring, installing, operating, and service
Conditions for safe operating
Documents / Resources

Safety Quick Start Guide
00825-0400-4975, Rev AA
Rosemount™975 Flame Detectors

Rosemount 975 series

The flame detectors series Rosemount 975 fulfills the requirements of the IEC 61508 for a Safety Integrity Level (SIL) 2 in a one-channel configuration or up to SIL 3 of IEC 61508 in a redundant configuration.

Certified product identification of the device

Kind of product: Infrared and ultraviolet flame detector series
Type designation: Rosemount 975HR4U, 975MR4U, 975UF4U, 975UR4U

Technical data:

Spectral response:	Infrared and ultraviolet bands
Supply voltage:	18-32 Vdc
Max. Power consumption:	300 mA
Max. current:	9.6 W
Output:	0-20 mA

Fault relay
Alarm relay
0-5 V

Applied standards

N1
IEC 61508 Part 1 – 7:2010
Functional safety of electrical/electronic/programmable electronic safety- related systems

N2
EN 54-10:2002 and EN 54-10/A1:2005
Fire detection and fire alarm systems Part 10: Flame detectors – Point detectors

Safety parameters

Safety function

The safety function of the Rosemount 975 flame detector series is to detect flames in which carbon dioxide (CO2) is produced in the combustion process and announce this over the 4-20 mA interface, analog output interface, and/or by opening the alarm-relay-contact.

Characteristics as per IEC 61508

Safety Integrity Level (SIL)| 2 (one-channel configuration) and 3 (redundant configuration)
---|---
HFT (intern)| 0
Device type| B
Mode of operation| Low demand mode and high demand or continues mode
Average ambient temperature| max. 55 °C
Main time to repair| 0 h
Proof-test interval| 365 days

Safety relevant parameters

| Rosemount 975HR4U, 975MR4U (IR)| Rosemount 975UF4U, 975UR4U (UV/IR
---|---|---
MAO| RYO| RY02| FDO| MAO| RYO| RYO2| FDO
As (fit)| 988| 1290| 1290| 835| 923| 1226| 1226| 770
AD (fit)| 988| 1285| 1285| 835| 923| 1221| 1221| 770
Am (fit)| 104| 107| 107| 102| 79| 82| 82| 77
ADD (fit)| 884| 1179| 1179| 732| 844| 1139| 1139| 693
5FF| 95%| 96%| 94%| 94%| 96%| 97%| 97%| 95%
DC| 89%| 92%| 88%| 88%| 91%| 93%| 93%| 90%
PFDavg (1001)| 5.E-04| 5.E-04| 4.5E-04| 4.5E-04| 3.5E-04| 4.E-04| 3.E-04| 3.E+04
PFD%sio| 5.%| 5.%| 5.%| 5.%| 4.%| 4.%| 3.%| 3.%
PFH (1oo1, 1/h)| 1.0E07| N/A| 1,0E07| N/A| 7.9E08| N/A| 7.7E08| N/A
PFH%_SIL2| 10.4%| N/A| 10.2%| N/A| 7.9%| N/A| 7.7%| N/A
PFDavg (1oo2)| 9.4E06| 9.6E06| 9,3E06| 9.2E06| 7.1E06| 7.3E06| 3.4E04| 6.9E06
PFD%SIL3| 0.9%| 1.0%| 0.9%| 0.9%| 0.7%| 0.7%| 3.4%| 0.7%
PFH (1oo2, 1/h)| 2.2E09| 2.2E09| 2.1E09| 2.1E09| 1.6E09| 1.7E09| 7.7E08| 1.6E09
PFH%SIL3| 2.2%| 2.2%| 2.1%| 2.1%| 1.6%| 1.7%| 7.7%| 1.6%

Remarks:

N/A.: Not allowed for high demand mode
RYO: Using only the alarm-relay for alarming
RYO2: Using alarm and acc-relay for alarming (serial connected contacts)
MAO: Using the 4-20 mA – Interface for alarming
FDO: Using the analog OUT interface for alarming
Failure rates of the electronic components as per Siemens SN 29500, calculated based upon an ambient temperature of 55 °C and statistical data of the sensor elements
The calculation was performed based on a proof-test interval T1 = 365 days.
Without knowledge of the partly redundant internal structure of the detector a calculation with other proof-test intervals (e.g., two years) leads only to an approximate result.

Guidelines for configuring, installing, operating, and service

The alert conditions according to SIL 2 can be implemented by an:

Alert signal via 20 mA current loop or
Alert signal via alarm relay and the fault relay

Conditions for safe operating

The flame detector shall consist only of the approved hardware and software modules.
The 24 V power supply must fulfill the requirements for PELV/SELV of EN 60950.
The automatic built-in test (BIT) must be activated.
The function of the Rosemount 975 Flame Detector (flame detector, function of the 0-20 mA interface, and relay functions) must be checked completely.

Using the 0-20 mA interface for alerting

The following parameters shall be set:

Automatic built-in test: On
Connected to 0-20 mA terminals

The following allowed output current must be supervised with an accuracy of ±5 percent.

Normal state: 4 mA
Warning state: 16 mA
Alarm state: 20 mA

Using the alarm relay contact for alerting

The following parameters shall be set:

Automatic built-in-test: On
Connected to normally closed (N.C.) contact of alarm relay terminals
Connected to fault relay terminals

The relay contacts (alarm and faulty relay) must be protected with a fuse rated at 0.6 of the nominal specified relay contact current.
The maximum contact rating that is allowed per SIL-2 is 30 Vdc.
The contact of the alarm relay opens if there is a fire alarm.
During the forwarding and evaluation of the alarm, the relay contact opens.

Using the alarm and acc-relay for alarming

The following parameters shall be set:

Automatic built-in-test: On
Connected to normally closed (N.C.) contact of alarm relay terminals and auxiliary relay terminals.
The contacts of alarm relay and auxiliary relay must connected serial.
Connected to fault relay terminals.
The relay contacts of auxiliary relay, alarm relay and faulty relay must be protected with a fuse rated at 0.6 of the nominal specified relay contact current.
The maximum contact rating that is allowed per SIL-2 is 30 Vdc.
The contacts of the alarm relay and the auxiliary relay open if there is a fire alarm.
During the forwarding and evaluation of the alarm, the relay contacts opens.

Using the analog voltage output for alerting

The following parameters shall be set:

Automatic built-in-test: On
Connected to analog voltage output terminal.
The following allowed output voltage must be supervised with an accuracy of ±20 percent.
- Normal state: 2 V
- Fault state: <1 V
- Alarm state: 5 V

The analog voltage output can be used as low demand only.

Other

The window of the sensor must be examined at appropriate time intervals for partial contamination.
The HART and the RS-485 interfaces must not be used for the transmission of the safety-related data.®

Emerson.com/Rosemount

Safety Quick Start Guide
00825-0400-4975, Rev. AA
June 2021

For more information: www.emerson.com

Rosemount