1. Overview

This article covers how to implement formula-based quality checks in iVendNext. Use this information to:
✔ Create dynamic formulas for inspections
✔ Apply mathematical and logical operations
✔ Troubleshoot common formula errors

Why Use Formulas?

• Validate product grades (A/B/C)

• Calculate averages/variances (e.g., pH levels)

• Enforce multi-parameter rules (e.g., "Weight must increase if density > X")

2. Prerequisites

Before creating formula-based checks:

1. Enable Quality Inspection in the Item Master

2. Create a Quality Inspection Template

3. Basic understanding of:

• Arithmetic operators (+, -, *, /)

• Comparison operators (>, <, ==, !=)

• Logical operators (and, or, in)

3. Formula Types & Syntax

3.1 Numeric Formulas

Validate calculations against numeric criteria:

# Example 1: Sum of readings < 100  

(reading_1 + reading_2) < 100  

# Example 2: Mean of readings > 50  

mean > 50  

# Example 3: Ratio constraint  

(reading_1 / reading_2) < 2.5  

3.2 Text/Non-Numeric Formulas

Validate text patterns or categories:

# Example 1: Exact match  

reading_value == "Pass"  

# Example 2: Value in list  

reading_value in ("A", "B", "C")  

# Example 3: Exclusion check  

reading_value != "Defective"  

3.3 Hybrid Formulas

Combine numeric and text logic:

# Example: Reject if "Color" is Red AND "Weight" < 10kg  

reading_value == "Red" and reading_1 < 10  

4. Step-by-Step Setup

4.1 Add Formula to Template

1. Open Quality Inspection Template

2. For a parameter:

• Check "Formula Based Criteria"

• Enter formula in Acceptance Criteria Formula

3. Save

4.2 Apply in Quality Inspection

1. Create a New Quality Inspection

2. Select the template → Formulas auto-populate

3. Enter readings → System auto-calculates results

5. Advanced Use Cases

5.1 Statistical Validation

# Standard deviation < 5  

std_dev < 5  

# 90th percentile > 100  

percentile_90 > 100  

5.2 Conditional Logic

# Reject if: Temperature > 30°C AND Humidity > 80%  

reading_1 > 30 and reading_2 > 80  

5.3 Cross-Parameter Rules

# Density must correlate with weight  

(reading_1 / reading_2) > 0.5  

6. Troubleshooting

Here’s a quick look at some common issues you might run into.

Pro Tip: Test formulas in Draft Mode before submission!