LWT
5-2-55, Minamitsumori, Nishinari-ku, Osaka 557-0063 JAPAN
Phone: +81(6)6659-8201 Fax:
+81(6)6659-8510 E-mail: [email protected]
EM-1975 Rev.4 P. 3 / 3
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TERMINAL ASSIGNMENTS
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2 3 4 5 6 7
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9 10 11 12 13 14 15 16
WIRING INSTRUCTIONS
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SCREW TERMINAL
Torque
: 0.8 N·m
CHECKING
1 ) Terminal wiring: Check that all cables are correctly
connected according to the connection diagram.
2 ) Auxiliary power input voltage: Check voltage across
terminal 9 – 10 with a multimeter.
3 ) Input: Calculate the calibration range and check that
the result is within the usable range.
Calibration Range [W] =
Measuring Wattage
(VT Ratio) × (CT Ratio)
4 ) DC output: Check that the load resistance meets the
described specifications.
5 ) Pulse output: Check that the load connected to the open
collector output is within 35 V DC @ 100 mA.
ADJUSTMENT PROCEDURE
This unit is calibrated at the factory to meet the ordered
specifications, therefore you usually do not need any cali-
bration.
For matching the signal to a receiving instrument or in case
of regular calibration, adjust the output as explained in the
following.
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HOW TO CALIBRATE THE OUTPUT SIGNAL
Use a signal source and measuring instruments of suffi-
cient accuracy level. Turn the auxiliary power supply on
and warm up for more than 10 minutes.
1 ) ZERO: Apply 0% input and adjust output to 0%.
2 ) SPAN: Apply 100% input and adjust output to 100%.
3 ) Check ZERO adjustment again with 0% input.
4 ) When ZERO value is changed, repeat the above proce-
dure 1) – 3).
MAINTENANCE
Regular calibration procedure is explained below:
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CALIBRATION
Warm up the unit for at least 10 minutes. Apply 0%, 25%,
50%, 75% and 100% input signal. Check that the output
signal for the respective input signal remains within accu-
racy described in the data sheet. When the output is out of
tolerance, recalibrate the unit according to the “ADJUST-
MENT PROCEDURE” explained earlier.
LIGHTNING SURGE PROTECTION
M-System offers a series of lightning surge protector for
protection against induced lightning surges. Please contact
M-System to choose appropriate models.