Rosemount Model 8800C Vortex Flowmeter
A-10
Failure Mode Alarm
If self-diagnostics detect a gross flowmeter failure, the analog signal
will be driven either below 3.75 mA or above 21.75 mA to alert the user.
Also, high or low alarm signal is user-selectable through the fail mode
alarm jumper on the electronics.
NAMUR-compliant alarm limits are available through the C4 or CN
Option. NAMUR-compliant limits are 3.6 mA (low) or 22.5 mA (high).
Saturation Output Values
When the operating flow is outside the range points, the analog output
continues to track the operating flow until reaching the saturation
value listed below; the output does not exceed the listed saturation
value regardless of the operating flow.
The 4–20 mA Saturation Values are 3.9 mA (low) or 20.8 mA (high).
The NAMUR-Compliant Saturation Values (Option C4 or CN) are 3.8
mA (low) or 20.5 mA (high).
Damping
Adjustable between 0.2 and 255 seconds
Response Time
Three vortex shedding cycles or 0.2 seconds, whichever is greater,
maximum required to reach 63.2% of actual input with the minimum
damping (0.2 seconds).
Turn-on Time
Less than four (4) seconds plus the response time to rated accuracy
from power up.
Transient Protection
The optional transient terminal block prevents damage to the
flowmeter from transients induced by lightning, welding, heavy
electrical equipment, or switch gears. The transient protection
electronics are located in the terminal block.
The transient terminal block meets the following specifications:
ASME B16.5 (ANSI)/IEEE C62.41 - 1980
(IEEE 587) Categories A, B
3 kA crest (8 20
m
s)
6 kV crest (1.2 50
m
s)
6 kV/0.5 kA (0.5
m
s, 100 kHz, ring wave)
Security Lockout
When the security lockout jumper is enabled, the electronics will not
allow you to modify functions that affect flowmeter output.
Output Testing
Current Source
Flowmeter may be commanded to set the current to a specified value
between 4 and 20 mA.
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