Hardy HI 2151/30WC Single-Scale Controller - Manual (Page 81)

Chapter 6 - Calibration
6-3
• The expected output from each load cell/point depends on
the mV/V rating of the load cell/point and weight.
• For example, a 2 mV/V load cell/point will respond with a
maximum of 10 mVDC at full weight capacity of the sys-
tem which includes the weight of the vessel and the weight
of the product as measured by the load cell/point.
• If the load cell/point weight capacity is rated at 1000
pounds, the load cell/point output will be 10 mVdc at 1000
pounds, 7.5 mVdc at 750 pounds, 5 mVdc at 500 pounds
and so on.
• A zero reference point will vary from system to system
depending on the "Dead Load" of the vessel. "Dead Load"
is the weight of the vessel and appurtenances only, with no
product loaded. In our example we will assume the dead
load to be 500 lbs. (See Fig. 6-2)
FIG. 6-2 MILLIVOLTS/WEIGHT SCALE
• Based on the example, the operating range for this scale is
5-10 mVdc with a 500 pound weight range. Understand that
after zeroing the instrument, the 0 reading on the instrument
refers to the zero reference point and not absolute 0 mVdc
or absolute 0 weight.
NOTE: Load cell/point measurements are checked with a digital volt meter at the summing
junction box or the J1 connector on the rear panel of the HI 2151/30WC or use Inte-
grated Technician. if using the IT Junction Box.
1
10
9
8
7
6
5
4
3
2
250 1000 750 500
WEIGHT IN POUNDS
M
ILLI
V
O
LT
S
D
C
DEAD LOAD 500#
ZERO REFERENCE POINT
MAXIMUM LOAD CAPACITY