Today I checked a loop with my meter and got 3.986 mA. At first glance, it looks off but actually, this is completely normal.
In real-world instrumentation:
• Transmitters have small accuracy tolerances
• Measuring devices also have slight error
• Wiring, temperature, and power supply can affect readings
So a value like 3.986 mA is essentially your 4 mA signal (lower range value).
You only need to worry if it drops closer to 3.8 mA or below, which could indicate a fault condition.
Lesson: Don’t chase perfection – understand the tolerance.
