5-5
Specifications and Reference Data
DNV Type Approval for Shipboard and Offshore Installations
If DNV Type approval is required, you must specify the Transient
Protector option (Option Code T1).
Transient Protection (Option
Code T1)
The transient protector helps to prevent damage to the transmitter
from transients induced on the loop wiring by lightning, welding, heavy
electrical equipment, or switch gears. The transient protection
electronics are contained in an add-on assembly that attaches to the
standard transmitter terminal block. The transient protector has been
tested per the following standard:
ASME B 16.5 (ANSI)/IEEE C62.41-1991 (IEEE 587)/ Location
Categories A2, B3.
1kV peak (10
3
1000 mS Wave)
6kV/3kA peak (1.2
3
50 mS Wave 8
3
20 mS Combination Wave
6kV/0.5kA peak (100 kHz Ring Wave)
4kV peak EFT (5
3
50 nS Electrical Fast Transient)
Loop resistance added by protector: 22 ohms max.
Nominal clamping voltages: 90 V (common mode), 77 V (normal mode)
Failure Mode
The Model 3144 and 3244MV transmitters feature software-driven
alarm diagnostics as well as an independent circuit designed to provide
separate, backup alarm output in case the microprocessor electronics
hardware or software fails.
The alarm levels are user selectable by the Failure Mode Jumper (see
“Failure Mode Jumper” on page 2-7). The position of the jumper
determines the direction in which the output is driven (HI or LO) in
case of alarm. The jumper switch feeds into the D/A converter, which
drives the proper alarm output even if the microprocessor fails.
The values to which the transmitter drives its output in failure depend
on whether it is factory configured to standard or NAMUR-compliant
operation. The values for each are as follows:
Location Classes:
Temperature D
Vibration B/C
Humidity B
Enclosure D
Standard Operation
Linear Output:
3.9
≤
I
≤
20.5
mA
Fail High:
21.0
≤
I
≤
23.0
mA
Fail Low:
I
≤
3.75 mA
NAMUR-Compliant Operation
Linear Output:
3.8
≤
I
≤
20.5
mA
Fail High:
21.0
≤
I
≤
23.0
mA
Fail Low:
I
≤
3.6 mA