Emerson Rosemount Apex, Reference Manual

Page: 38 / 124

Reference Manual
00809-0100-4731, Rev FA
April 2003
APEX
™
and APEX Sentry
™
Radar Gauge
2-22
ELECTRICAL
INSTALLATIONS
Check Processor
Switches
Electronic boards are electrostatically sensitive. Failure to observe proper
handling precautions for static-sensitive components can result in damage to
the electronic components. Do not remove the APEX or APEX Sentry
electronic boards. The gauges are calibrated with particular boards; swapping
boards will negatively affect accuracy.
The gauge monitors its own operation. This automatic diagnostic routine is a
timed series of checks repeated continuously. If the diagnostic routine detects
a failure in the gauge, the 4–20 mA output is driven upscale (high) to 21 mA or
downscale (low) to 3.75 mA, depending on the position of Switch 1.
Security write protection prevents unauthorized access to configuration data
through the optional integral display or HART Communicator.
Figure 2-18. Radar Gauge
Processor Switch Settings
Table 2-3.
APEX Radar Gauge Switch Settings
Switch Bank Description Default Setting Position Settings
Switch 1 4–20 mA Alarm Output High (ON) ON = High, OFF = Low
Switch 2 Security Write Protection Disabled (OFF) ON = Enabled, OFF = Disabled
Table 2-4.
Analog Output: Standard Alarm Values vs. Saturation Values
Level 4–20 mA Saturation Values 4–20 mA Alarm Value
Low 3.9 mA 3.75 mA
High 20.8 mA 21.75 mA
Table 2-5.
Analog Output: NAMUR-Compliant Alarm Values vs. Saturation Values
(option codes C4 or CN)
Level 4–20 mA Saturation Values 4–20 mA Alarm Value
Low 3.8 mA 3.6 mA
High 20.5 mA 21.0 mA
ON
1 2
Microprocessor
Chip
4–20 mA Alarm
Output Switch
Security Write
Protection
Switch
PROCESSOR BOARD
LEVEL-0025A