Step 4 - Chase the "High Number" (mA)

Of all steps in the 2-Wire Troubleshooting process, this is the step that is most often misapplied. By isolating troubleshooting to one wire, we focus troubleshooting on the worst field issue. By "Chasing the High Number", we focus on finding the worst field issue (highest mA) relative to field position, and eliminate all other distractions. Often, by focusing on resolving worst field issue first, other erratic 2-Wire behaviors resolve & troubleshooting time is reduced significantly.

Before beginning, keep the following 2-Wire tips in mind:

• The highest number will always be recorded at the controller. You will never gain current as you move away from the controller.
• The "High Number" is high relative to the first value recorded at the controller. I.e. I record 350mA on the Red Wire of my controller. I go halfway in my system, passing 10mA worth of decoders. I see 330mA on my clamp meter. The High Number is 330mA.
• At a 3-Way splice, the highest number will indicate the point closest to the controller. I.e. I see 30mA, 340mA & 341mA at a splice. I will chase 340mA. 
• Ignore values that seem "too low". 

1. Determine the half-way point of your system (in terms of the furthest decoders) and take your first measurement.
2. If the number is still high, the problem is still ahead of you (towards the further decoder).
3. If the number is closer to your "benchmark", your problem is behind you (towards the controller).
4. Continue to chase the "high number" by splitting the system in half.
   
   Use this interactive guide for additional assistance: Interactive 2-Wire & Decoder Troubleshooting Guide

To continue troubleshooting access: Step 5 - Locate & Resolve the Problem