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

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 DM-700 Gas Detector only covers the
use of the standard analog 4-20 mA output.
Safety-Certification of the DM-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, change of range, replacing plug-in electrochemical sensor, and
replacing ITM module.
4 VALID INPUT RANGE
DM-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 (<1.8 mA).
Note:
The DM-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 DM-700 will perform all critical diagnostic functions within 1 hour. This is the worst case diagnostic detection time.
6 CERTIFICATION
The DM-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 DM-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 DM-700 is SIL2 certified per IEC 61508-2010 with an HFT=0.
The DM-700 is a Proven-In-Use (PIU) device per IEC 61508-2010. The revision levels of the SIL 2 certified DM-700
sensor is noted as Main PCB Rev 1, Sensor Barrier PCB Rev 02, and Firmware V2.21M.
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 DM-700 S.
8 CONSTRAINTS
The safety function of the Detcon Model DM-700 Toxic Gas Sensor is limited by the following constraints:
- Shall not be used in continuous mode applications
- Toxic gas is not constantly present (e.g. for long periods of more than 24 hours)
- The maximum load on the 4-20mA output of the DM-700 is 1KΩ with 24VDC input power and 500Ω with
12VDC input power