Sensor Electronics SEC Millenium Series Instruction And Operation Manual page 470

Warm-up
When power is applied to the detector, it enters a one (1) minute warm-up mode. The output current will be
0.8 mA during the warm up time period. At the end of the warm-up period with no faults present, the
detector automatically enters the normal operating mode (4 mA). If a fault is present after warm-up, the
detector current output will indicate a fault. See the following chart for fault code status.
Normal
In the normal operating mode, the 4 to 20 mA signal levels correspond to the detected gas concentration.
The detector continuously checks for system faults or initiation of calibration and automatically changes to
the appropriate mode.
The 4 to 20 mA output of the SEC MILLENIUM is a non-isolated current source.
Once the fault is cleared the SEC MILLENIUM will atomatically resume normal operation.
Current Output and Corresponding Status
Current Output
0-20 mA Normal measuring mode
0.0 mA Unit Fault
0.2 mA Reference channel fault
0.4 mA Analytical channel fault
0.8 mA Unit warm up
1.0 mA Optics fault
1.2 mA Zero drift fault
1.6 mA Calibration fault
2.0 mA Unit spanning
2.2 mA Unit zeroing
4.0 mA Zero gas level
20.0 mA Full scale
20.1- 23 mA Over-range (> 100% full scale)
7
Status.