Start-Up; Preliminary Checks; Zero Check; Dynamic Zero Compensation - ABB MAG-SM Instruction Bulletin

Electromagnetic Flowmeter Converter
3.

Start-Up

3.1

Preliminary Checks

Before turning on the instrument check that the
• coordination flowmeter primary/converter is correct
(essential for converters with fixed ranges and for flowmeter
primaries using ac magnetic fields); that the instruments
which are to be connected together have the same last
number; e.g. A1 connected to B1, X 001 to Y 001 or
A2 to B2, X 002 to Y 002 as noted on the Instrument Tag.
• wiring connections are in agreement with the
Interconnection Diagrams.
• flowmeter primary has been properly grounded (see
Instruction Bulletin for the Flowmeter Primary).
• ambient conditions are within the specified limits.
• supply power values agree with the values listed on the
Instrument Tag.
• flow direction coincides with the direction indicated by the
arrow on the flowmeter primary.
• parameters are configured for the operating conditions.
• system zero has been adjusted using the software, (see
Section 3.2 Zero Check).
• converter parameter "Operating mode" and "Primary type"
in the submenu Primary are set correctly. Check the
contrast setting on the display. A small screwdriven can be
used to adjust the contrast of the display for the local
ambient conditions, see Page 53.
• all meter location parameters have been stored in the ext.
EEPROM on the connection board. When interchanging a
converter module (failure) in the past it was necessary to
reenter all the parameters. This is no longer required if the
meter location parameters have been stored in the ext.
EEPROM on the connection board (see Pages 26 and 38
and Section 5.1.5).
!
Note:
The values of the settings and the options included with
the metering system can be recorded on Page 52 or on
the accompanying card. The card is located behind the
converter module in the field mount housing. The 4
housing screws must be unscrewed to gain access to
the module. The card is tied to the connection board on
converter card in the 19"-Insert.
16
General Information
• If there is no indication of flowrate it may be possible that the
singal cable connections are reversed. Interchange the
leads connected to terminals 1 and 1S with those at 2 and
2S at the flowmeter primary. For flowmeter primaries with
preamplifiers, only the leads connected to terminals 1 and 2
are to be interchanged.
• The locations of the fuses and the fuse values can be found
in Figs. 18 to 20.
3.2

Zero Check

At start-up or when checking the system the system zero of the
converter should be set. The flowrate in the flowmeter primary
must be brought to absolute zero. The metering tube must be
guaranteed to be completely filled with fluid. The zero can be
adjusted automatically or manually by using the parameter
"System zero". Select the parameter with ENTER and use the
arrow keys to select "automatic", if desired, and activate by
pressing the ENTER. During the automatic adjustment
procedure the converter counts from 0 to 256 and the counts
displayed in the 2nd line while the adjustment is executed 7
times. The system zero adjustment then terminates. The
adjusment prodedure takes approx. 20 seconds and the zero
value should be within the range of ±1500 Hz.
3.3

Dynamic Zero Compensation

An automatic zero adjustment can be initiated from the
converter input (terminals A1 – G2). The flowrate in the
flowmeter primary must be brought to absolute zero. The
metering tube must be guarantedd to be completely filled
with fluid.
During the automatic adjustment procedure the converter
counts from 2 to 256 and the counts displayed in the 2nd line
while the adjustment is executed 7 times. The zero value
should be within the range of ±1500 Hz.
If the adjustment value is outside of these limits – causes: large
noise signals (check ground connections), fluid level unsteady
(hydraulic problems, shut off device leaks), metering tube not
full (pipeline can drain, shut off device leaks) – the message
"Warning" is displayed in the 1st line of the converter. This
message can only be cleared by pressing the ENTER-key.
4.

Maintenance

The converter is maintenance free. Observe the "Introductory
Safety Notes for the EMF System" and the "Hazardous Material
Information" at the beginning of this Instruction Manual.