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ESP-LXD 2-Wire Decoder Control System Installation & Troubleshooting Guide
- Use a Clamp Meter to measure the Amp Draw of the 2-wire path cable conductors at the last
working decoder and the first non-working decoder. Note any discrepancy in the readings.
You must know the number and type of each decoder downstream to know what the mA
reading up should be reading (see Calculating the total system mA draw section for more
information).
- The problem may be caused by a decoder or LSP-1 Line Surge Protector damaged by a
lightning power surge. The controller will exit Short Finding Mode when this damaged
decoder or line surge protector is disconnected from the 2-wire path.
Earth ground fault / 2-wire path cable/splice leaking to earth ground
A 2-Wire Path Cable conductor is leaking to ground possibly due to a bad wire splice, or a
nicked or damaged cable. This issue may come and go depending on the soil moisture level.
When the soil is very wet the problem will be worse than when the soil is dry.
Controller diagnostics
- Turn dial to Test All Stations / Check System; Select 2-Wire Diagnostics
- Select Line Survey. Note the Milliamp (mA) reading. The mA reading will be higher than
normal when current is leaking to ground. You must know the number and type of each
decoder in the system to know what the mA reading should be reading (see Calculating the
total system mA draw section for more information).
- Disconnect each 2-wire path cable one at a time from the controller ESPLXD-M50 Decoder
Module. Recheck the Line Survey to isolate which segment of the 2-wire path has the
ground fault.
- Find a decoder location about half-way down the 2-wire path cable. Disconnect the splices.
Check the Line Survey to see if the ground fault has been isolated. If the Line Survey is
normal, the problem is downstream of this location. If the Line Survey still shows the ground
fault, the problem is between this location and the controller. Keep disconnecting segments
of the 2-wire path until you isolate the problem.
2-Wire Path diagnostics
- Turn the controller dial to 2-Wire Diagnostics; Select Short Finding; Turn Short Finding Mode
On. Use a Clamp Meter to measure the Amp Draw of the 2-wire path cable conductors at
various splice locations. Note any discrepancy in the readings. You must know the number and
type of each decoder downstream to know what the mA reading up should be reading (see
Calculating the total system mA draw section for more information).
