Input Diagnostic Module - Broken Wire Detection
Overview
- Detect boken wires, shorts, and faults
- Differentiates between actual open/closed conditions and erroneous signals caused by contact bounce, shorted wiring, broken wiring, or ground faults.
- Integrates with industrial control systems and programmable logic controllers
- Eliminate false shutdowns, simplify troubleshooting, and provide early detection of faulted field wiring.
Features
- Accept inputs from any field device with an open/closed contact
- Differentiate between shorted wiring and a closed contact
- Differentiate between broken wires and an open contact
- Detect ground faults
- Communicate normal, active, and faulted conditions to PLCs or other control system
Operation
If your system requires switch monitoring of a closed contact, a short in a sensor’s field wiring appears as a closed contact to industrial control systems. With the PRETECH IDM, a “FAULT” (shorted wire) signal is sent to the system and the “SHORT” indicator lamp illuminates on the front of the module. Without this protection, the true position of the field sensor would be undetected by the control system.
If your system requires switch monitoring of an open contact, a broken wire appears as an open contact to industrial control systems. With the PRETECH IDM, a “OPEN” (broken wire) signal is sent to the system and the “OPEN” indicator lamp illuminates on the front of the module. Without this protection, the true position of a field sensor would be undetected by the control system.
The module works with a Loop Terminator (LT) which is a small environmentally sealed passive device installed at end of the monitored loop closest to the switch. This configuration allows the IDM to monitor the entire loop. A normally open contact is provided to alarm the DCS, SCADA, or PLC that the field switch has changed state. Additionally, a normally closed contact is provided to alert the operator that a fault condition exist on the IDM.
Interfaces
- Fault signal contact to communicate the field device or wiring has failed.
- Redundant active contacts to communicate that a true open or closed contact has been detected in the field device.
- 12Vdc monitoring power source.
- Remote reset capabilities
Front Face Provides Clear Status
As a part of our switch monitoring or dry contact monitoring design, our module gives immediate indication of the status of the switch or dry contact loop being monitored. We provided LEDs on front face clearly display the conditions of the switch/contact (open or closed) Normal or Active and the field wiring status Open, Short or Ground. These loop conditions are communicated through the use of of the auxilliary dry contacts back to the SCADA or PLC system.
DIN Rail Mounted
Our switch monitoring or dry contact monitoring solution provides loop monitoring through a module similar in size to most DIN rail mounted components. Fit into any DIN rail application.
Basic Schematic
Example Configuration with PLC
