ABB MT series, Руководство пользователя

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4.7.3.3 4–20mA Loop Check
Without HART
LOOP TEST is a function designed to simulate transmitter out-
put at various levels and confirm readings from a separate loca-
tion. The LOOP TEST may be performed at any mA OUTPUT be-
tween 3.61 and 21.00. To perform a LOOP TEST: 1. Press and hold
the SELECT button for 2 seconds. 2. Scroll UP or DOWN to select
each digit for the desired mA OUTPUT. 3. Press the SELECT but-
ton to set the digit and move to the next digit in sequence. 4.
After the last digit is set the mA OUTPUT will change to the de-
sired level. (Another mA OUTPUT may be selected by repeating
steps 1 through 4.) 5. Scroll DOWN to END MENU. (The mA OUT-
PUT will return to normal operation after pushing the DOWN
arrow) 6. Pressing the SELECT button now will return you to the
main screen.
With HART communications
With the transmitter installed, wired and powered in its field
location and power supplied to the loop, connect a HART
handheld device to the loop across a 250 ohm resistor. Using the
Loop Test feature of the HART handheld, drive the output of the
transmitter to 4mA and 20mA. Confirm the proper reading at the
indication or control side of the loop.
Minor adjustments to the output of the transmitter may be
made using the DAC Trim (Digital/Analog Convertor) feature.
During normal operation, it is not necessary to perform mainte-
nance on the MT5000 transmitter. Routine calibration of the
transmitter is not necessary. The MT5000 contains an EPROM
which will store calibration in case of an out-age or electronics
replacement.
4.8 Verify Proper Power-up of the Transmitter
Use a mA meter to measure the output current. When power is
applied, the output should go to 4.00 mA for at least 1 second,
and then to either the measured level or an alarm condition out-
put. If this does not happen, the transmitter may not be receiv-
ing enough power, or the main electronic is defective. Excessive
current above 21 mA is also an indication of improper power-up
or defective electronics.
4.9 Module Replacement or Upgrade
The MT5000 transmitter is equipped with modular electronics
which may be removed from the housing. An EPROM located in
the transmitter housing will maintain the settings of the trans-
mitter if the electronics are removed. This al-lows the replace-
ment of failed electronic modules and upgrading of electronics
or transmitter software without loosing calibration and setup
configuration.
Before removing the electronics module for replacement or up-
grade, the MT5000 transmitter should be taken out of service. To
remove the electronics module, simply loosen the 2 mounting
screws, unplugging the module from the housing and replace it
with the new module.
The software revision of a transmitter can be identified by a tag
on the back of the electronics module. The date code of the soft-
ware revision will appear as a series of numbers such as MT
090414.00.001. The type of module will be identified on the same
tag with a code such as M7A-MT5 or M7B-MT5.
4.10 Retirement Date for MT5X00 as a Functional Safety Device
MT5X00 instruments shall not be used in a Safety Instrumented
Function (SIF) after December 31
st
, 2022. After this date, MT5X00
instruments can only be used in applications where IEC 61508
functional safety rating is not required.