Detcon FP-700 SIL 2 Safety Manual - Manual (Page 2)

3 DESIGN
The Model FP-700 is a catalytic bead type combustible hydrocarbon gas detector that is classified as a Type B smart
device according to IEC61508. The FP-700 sensor provides a 4-20 mA output that is proportional to combustible gas
vapor concentrations in the ranges of 0-100% LEL The FP-700 contains extensive self-diagnostics and is programmed to
send the current output to a specified failure state (0 mA) upon internal detection of a failure. A Modbus RS485 serial
output is available in addition to the analog signal output. The Safety Certification for the FP-700 Gas Detector only
covers the use of the standard analog 4-20 mA output.
Safety-Certification of the FP-700 includes the 4-20 mA output. The RS-485 Modbus signal output is not part of
the SIL Certification.
Note: Proper analog signal loop resistance must be installed as documented in the instruction manual to enable proper
4-20 mA signal function. The end user must perform zero and span calibrations after any significant configuration
changes or repair events. These include: restore defaults, replacing plug-in sensor, and replacing ITM module.
4 VALID INPUT RANGE
FP-700 fault annunciation is provided on the 4-20mA signal output loop by signaling to 0mA current output level for at
least 5 seconds. The receiving device must be programmed to indicate an out-of-range condition when current levels reach
overcurrent (>21.5 mA) or undercurrent (< 1.3 mA).
Note: The FP-700 analog signal output is not safety-rated during detector warm-up, configuration mode, calibration
mode, and during signal output loop testing. Alternative means should be used at the jobsite to ensure facility safety
during these activities.
5 DIAGNOSTIC RESPONSE TIME
The FP-700 will perform all critical diagnostic functions within 2 hours. This is the worst case diagnostic detection time.
6 CERTIFICATION
The FP-700 Safety-Certified version is certified by exida® to IEC 61508 for single input use in low and high demand, SIL
2 Safety Instrumented Systems. The FP-700 sensor is SIL2 certified as an individual component, but it can be used as
part of a larger Safety Instrumented Systems as long as it is applied per the guidelines of this Safety Manual.
The FP-700 is SIL2 certified per IEC 61508-2010 with an HFT=0.
The revision levels of this SIL 2 certified FP-700 sensor is noted as Main PCB Rev 1, Amplifier PCB Rev 2, and
Firmware V10.23N.
7 SAFETY – CERTIFIED PRODUCT IDENTIFICATION
The model number printed on the label will include the character “S” in the model number string, indicating exida®
approval for SIL 2 standard. Example: Model FP-700 S.
8 CONSTRAINTS
The safety function of the Detcon Model FP-700 Combustible Gas Sensor is limited by the following constraints:
- Shall not be used in continuous mode applications
- The maximum load on the 4-20mA output of the FP-700 is 1KΩ with 24VDC input power and 500Ω with
12VDC input power. The minimum load on the 4-20mA output is 10Ω.