Tecnetics Industries Tecweigh 20, Operation Manual

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Do not run power or communication wires near equipment that is a source of electrical
“noise”. This includes not only 240/480 VAC motor wires, but also 120 VAC
wires.
•
Always take static precautions when handling PCB’s (grounded wrist straps, static
bags, etc.)(See Section 1.08).
•
Never electrically weld near or on the scale or WP20, this can destroy the PCB’s,
load cells, or LVDTs (See Section 1.09).
•
Lightening storms can destroy PCBs. This can either be caused by electromagnetic
radiation or voltage spikes generated in the power conductors. If after a lightening
storm the WP20 fails to work, you might need to replace both the WP20 and SC
PCBs. Contact the
Tecweigh Service or Parts Departments (Section 2.01) to determine
replacement part requirements. Note that lightening strike damage is not covered
under the warranty.
Speed sensor options…
Low belt speed or high electrical “noise” environments might require using some of the SC300
or SC400 signal conditioner speed sensor options as defined below. Experiment with them one at
a time to determine which combination results in the smoothest belt speed reading. Contact the
Tecweigh Service Department (Section 2.01) for assistance if needed.
SW1
Pos1--ShuntR-- when ON, a portion of the voltage produced by standard and heavy duty speed
sensors is grounded out, which prevents damage caused by high speed belts. This switch must be
ON unless a magnetic pickup, open collector, or TTL type speed sensor is used.
Pos2--O.C.--turn ON to add a pull-up resistor when using an open collector type speed sensor.
Pos3--Noise--when ON, lower level electrical “noise” is grounded out, but a stronger speed
sensor signal is required.
Pos4--Filter--When ON, attempts are made to smooth the speed signal and ignore electrical
“noise”.
SW2
Pos1--when ON, the measured speed is multiplied times 10. Try using this option if the belt
speed is less than 15 feet per minute. The scale must be recalibrated per section 7.04.
Pos2--when ON, a fixed simulated SPEED for trouble shooting is produced. The SPEED value
displayed on the WP20 will equal 200 times the Speed Span Parameter (Section 6.02.18). Use
this option to remove the speed sensor as a potential problem when troubleshooting.
Pos3--when ON, the resistance to false belt speeds due to vibration is increased. However, lower
belt speeds (less than 20 feet per minute with the standard speed sensor) might not be detected.
Pos4—when ON, decreases the resolution of the load cell signal for backwards compatibility to
WP20’s with the WP20-02B main processor board. Contact the
Tecweigh Service Department
(Section 2.01) for further details when using this option.