VAF instruments OILCON MARK 6M, Техническое руководство

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9.5 DIFFERENTIAL PRESSURE TRANSMITTER – ABB
Do not open the cover from the amplifier with active DC power supply in hazardous ara.
9.5.1 Zero adjustment of DPT – ABB
1. Keep the transmitter energised for at least 10 minutes.
2. Remove the covers from the DPT electronics housing and slide away the tagplate.
3. Connect an ammeter to the “TEST” terminals (ext.meter + and -) of the transmitter as shown
is drawing
0810-2010
.
4. Check that the “Write protection switch” is switched to “DISABLED”.
Refer to the illustrations in drawing
0899-1259
.
5. Apply the lower pressure value.
6. Wait for the pressure to stabilise.
7. Press the “Z” button (under the tagplate on the DPT) for a few seconds as shown in drawing
0899-1259
.
The lower pressure value should then correspond with an output of 4mA.
8. Remove the ammeter, set the “Write protection switch” to “ENABLED” and close the covers.
Ensure that the sealing ring is installed otherwise the transmitter is not in accordance with
IP67.
NOTE:
After adjustment, the transmitter should be kept energized for about 10 seconds to write
the
adjustment results into the memory.
9.5.2 Span adjustment of DPT – ABB
1. Keep the transmitter energised for at least 10 minutes.
2. Remove the covers from the DPT electronics housing, slide away the tagplate and read the
calibration data plate affixed to the inside of the cover.
3. Connect a suitable pressure gauge and air supply to “+” side of the DPT. Make sure that “-”
side vents to atmosphere.
4. Connect an ammeter to the “TEST” terminals (ext.meter + and -) of the transmitter as shown
is drawing
0810-2010
.
5. Check that the “Write protection switch” is switched to “DISABLED”
Refer to the illustrations in drawing
0899-1259
.
6. Apply pressure shown as “upper calibration value” on calibration data plate of the DPT.
7. Wait for the pressure to stabilise.
8. Press the “S” button (under the tagplate on the DPT) for a few seconds as shown in drawing
0899-1259
.
The upper pressure value should then correspond with an output of 20mA
9. Set the pressure back to the lower pressure value and check that the output is 4mA.
10. After adjusting the span as mentioned above, set the “Write protection switch” to
“ENABLED” and close the tagplate.
11. Remove air tools and ammeter and close the covers. Ensure that the sealing ring is installed
otherwise the transmitter is not in accordance with IP67.
NOTE:
After adjustment, the transmitter should be kept energized for about 10 seconds to write
the adjustment results into the memory.
WARNING:
IN HAZARDOUS ZONES WITH EXPLOSION PROOF REQUIREMENTS THE COVER
MUST BE HAND TIGHTENING AND SECURING WITH THE LOCKING SCREW.