Ohmart Vega W-4510, Техническое руководство по аппаратному обеспечению

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Setup
72 W-4510 Weigh Scale Technical Reference Manual
Measurement cutoff
Some belt scale applications have the belt scale running empty for prolonged periods. If there
is a buildup of product sticking to the belt, the gauge measures and totalizes this product
when the not actually receiving the product. The measurement cutoff feature turns the
measurement off in the frequency input block when the measurement drops below a setpoint.
The Measurement Cutoff Setpoint is entered in Standardize Compensated Counts.
Note
The setpoint is entered as counts above the zero point. The gauge keeps track of the zero
point, you enter the counts. For example, if the cutoff should trigger at 20 counts above the
cutoff, enter 20 in the setpoint location.
Some applications have a large noise factor or very light loading. This makes it hard to
distinguish between an empty belt and a low product. The Cutoff Time Constant feature
provides for those cases requiring filtering of the raw counts used to trigger the cutoff
function. This filtering is independent of the measurement process and does not affect the
measurement in any way. As the Cutoff Time Constant is raised, the noise factor is reduced
and the cutoff response time is increased. A Cutoff Time Constant entry is required if using
the Measurement Cutoff feature. An entry of 1 gives the fastest response just as in the
normal measurement time constant entry. The Measurement Cutoff function will not operate
with an entry of zero for the Cutoff Time Constant.
Note: The cutoff time constant should be set as low as possible while still getting reliable
cutoff indications.
When the measurement is actually cut off, there are two indications of the condition. The
measurement processing in the frequency Input block will be zeroed from the normalized
count location on and the Cutoff Flag will contain a one. The Cutoff Flag will be zero with the
channel is in normal operation. You can use the Cutoff Flag to set an alarm, indicate an “end
of batch”, and so forth.
Refer to page 130 for the Frequency Input Block locations.