Rice Lake Condec UMC600IS - Manual (Page 34)

Calibration 31
4.3 Five-Point Linear Calibration
There are five calibration points (La, Lb, Lc, Ld, and Le) that can be entered sequentially. Calibrations using
fewer than five points will linearize the curve up to the last data point. The curve is then extrapolated from the last
entry point. For best results, use values of 20%, 40%, 60%, 80%, and 100% of full scale for the five linearization
points.
1. Turn on Option 6 (see Section 3.3.5 on page 23).
2. After performing a zero calibration as described in Section 4.1, place the first test weight on the scale
platform. Allow ten or more seconds for stabilization (motion LED goes out).
NOTE: Straight averaging is applied during calibration.
3. Enter test weight value for the first calibration point using the numeric keyboard.
4. When the display is correct, press the ENT key. The display will read CAL briefly. The value of the last
calibration point entered will then appear with a flashing display prompt L_ indicating the next
calibration point to be entered (Lb, Lc, Ld, or Le).
5. Repeat Steps 2, 3 and 4 for Lb, Lc, Ld, and Le with the appropriate test weights.
6. Recheck the zero weight by emptying the scale.
NOTE : AZM is off during calibration. Dead load display provides signal reference.
7. When complete, open all switches on SW1.
8. Re-install faceplate overlay and bracket. Tighten the knurled fasteners. Seal the unit if used in a
legal-for-trade application.
Note: If the response is more critical within a certain range, four of the five points can be in that area. The fifth point is
always 100% full scale.
4.4 Calculations Example
Capacity = 200,000 lb x 20 lb
Number of graduations = 200,000 ÷ 20 = 10,000
Configuration:
• Parameter 1 = 100 (10,000 graduations)
• Parameter 2 = 20 (resolution)
• Parameter 3 = 0 (no decimal point)
Other Factors to Note
AZM/PAZ: 1.9% x 200,000 = 3800 lb
Overrange: 103% x 200,000 = 206,000 lb
Minimum calibrated load: 10% x 200,000 = 20,000 lb
Analog Sensitivity
Analog signal input range: 0.7 to 3.2 mV/V
Analog signal sensitivity: 0.3 µV/graduations at 20,000
For H-44 requirements, use a factor of 4 (1.2 µV/grad). If the lower signal range is used for calibration, the
indicator may fail acceptance testing with 0.3 µV/grad.
NOTE: Check for a minimum live load of 12 mV for 10,000 graduations. If less than 12 mV, increase the number of
graduations accordingly.
Live Load Signal Range
The following table gives examples to determine the live load signal range:
Load Cells Rated at 2mV/V Rated at 3mV/V
5V Excitation 2mV/V x 5V = 10 mV 3mV/V x 5V = 15 mV
Dead load (est) 2 mV 5 mV
Live load 8 mV 10 mV
Table 4-1. Live Load Range Signal Range