Spectrex Quasar 900 Open-Path Gas Detection System - Manual (Page 28)

SafEye TM Quasar 900 Gas Detector
16 System Setup
Table 5: Standard (default) 0-20mA Current for the Gas Channel
Current Reading Status and Description
0mA +0.3mA Fault in 0-20mA loop
1mA ±0.3mA Zero Calibration (In Progress), Fault 2
2mA ±0.3mA Fault 1 (non-Critical)
2.5mA ± 0.3mA Misalignment fault
3mA ±0.3mA “Maintenance Call”
4mA±0.5mA No gas present
4-20mA Continuous measuring of gas concentration at a
range between 0 and full scale. For methane and
propane
This translates to 3.2mA per LEL.m and for ethylene
to 2mA per LEL.m.
21mA Concentration is over the range limit (more than full-
scale concentration).
3.3.2 RS-485 Interface
The RS-485 input/output sends complete data information to a PC and
receives data or control commands from the PC. The protocol is Modbus
compatible. The communication with the PC that is operated through the
interface is executed only when used with appropriate host software.
3.4 System Setup
This section includes the following topics:
 Detection Function Programming, page 16
 Detection Setup Function, page 17
 Detector Default Setup, page 18
3.4.1 Detection Function Programming
The SafEye Quasar 900 incorporates several functions that can be set by the
customer using:
 Host software. Refer to manual TM 888050 for programming
instructions.
 Handheld unit (P/N 799810). Refer to manual TM 799060 for
programming instructions. The connection of the handheld to the
detector is fast and intrinsically safe and allows function change with no
need to open the detector.