Hidden loop problems can lurk in your 4 to 20 milliamp loop wiring especially after floods. Bring your plant up safely and quickly by detecting moisture contamination in 4 to 20 milliamp loop wiring only by using PIE Calibrators with Patented LeakDetect.
Can you find hidden loop problems? When your process control plant has experienced a flood, or whenever you suspect that water has gotten into the conduits or junction boxes, there are a few courses of action you can take.
High risk, no up front costs or time
The easiest thing to do is to assume that there are no hidden loop problems, ignore the issue, and bring up the process without checking for the presence of water in the control loops.
Low risk, high up front cost and lots of time
The hardest and most time consuming preventive maintenance is to open up every junction box and raceway to look for water. Some junction boxes may be missed, or there may be moisture lurking elsewhere in the wiring causing undetected problems.
No risk, low up front cost and time saving
You can grab a PIE diagnostic calibrator with patented LeakDetect to find hidden problems due to moisture in flooded junction boxes or in the loop wiring. Simply disconnect the PLC or loop power supply and replace it with the PIE Calibrator. The PIE will power up the loop and instantly display any leakage current in the loop that is uncontrolled by the transmitter (see photo).
Once you have determined which loops have moisture problems you can then proceed to open junction boxes and raceways, only in the problem loops, and dry them out. This saves you manpower and time, helping you bring the plant back online quickly and safely.
Prevent small problems from becoming major plant failures
PIE diagnostic calibrators offer powerful troubleshooting tools that offer visibility to the health of your loop that is not possible with any calibrator brand on the market. LeakDetect allows technicians to find and fix undetected problems before they cause quality issues or become catastrophic failures – ending in poor product, injury, loss of life, or equipment damage. Common loop problems caused by moisture, corrosion and contamination left unchecked can lead to dangerous conditions that are easily avoided with the innovative technology in the PIE diagnostic calibrators.
Even the most common small errors caused by loop wiring issues can lead to inferior product, lost production time and risk to personnel. Intrinsically safe loops are protected by barriers only against extreme overvoltage and over current conditions but allowing significant ground faults to go undetected. PIE’s unique and powerful LeakDetect technology quickly and easily finds a fault that would otherwise go undetected. These undetected faults could lead to potentially disastrous outcomes.
Have you ever replaced a “faulty” transmitter only to find the problem was somewhere else in the loop? And did you end up throwing the transmitter away after you fixed the other problem “just in case” the transmitter was faulty?
If you find a loop where the transmitter is calibrated correctly but all the readings elsewhere in the loop have a fixed offset this is due to a Zero Shift. This Zero Shift is typically caused by some of the current in the loop bypassing the transmitter. If you have some loops that are erratic after it rains there may be moisture present in a junction box or where insulation has broken down.
Only a PIE Calibrator with patented LeakDetect can find all these hidden problems. Turn on LeakDetect and use the PIE diagnostic calibrator to power up the loop. Any current that isn’t controlled by the transmitter or other current control element will be clearly indicated as leakage on the PIE calibrator display.
LeakDetect allows technicians to troubleshoot loop problems with ease and confidence – minimizing risk and maximizing process uptime.
Hidden Problem Found with LeakDetect
Sealed junction box is dry and the control system is operating within parameters.
Sealed junction box is wet* and the control system is operating with a fixed offset of 0.51 milliamps!
Dangerous loop left undetected
The flooded junction box goes undetected and the control system potentially goes further out of control until…
Hidden problem is detected by the PIE diagnostic calibrator. The flooded sealed junction box is emptied and the control system is once again operating within parameters. The product, equipment, and personnel are safe!
* The value of the current leak increases when the water in the junction box is contaminated with rust, salt, or process chemicals.