SPX Radiodetection PCM+, Operation Manual

Page 1: ...PCM Radiodetection s world leading Pipeline Current Mapping system Operation Manual l Issue 4 l October 2009 90 PCMPLUS APP ENG 04 ...

Page 2: ... some product changes may have taken place after this user manual was published Contact your local Radiodetection dealer or visit www radiodetection com for the latest information about the PCM product family including this manual Important Notice Radiodetection Receivers detect almost all buried cables and most conductors but there are some which do not radiate signals and which Radiodetection Re...

Page 3: ...Pinpointing a Target Line 12 4 2 Peak Procedure 12 4 3 Null Procedure 12 4 4 Depth and Current Measurement 12 4 5 Current Direction 13 4 6 Mapping Current Measurements 13 4 7 Using dBmA for Pipeline Current Mapping 14 Section 5 Taking Measurements 16 5 1 Pipelines and Distribution Systems 16 5 2 Pipelines and Pipeline defects 17 Section 6 Applications 18 6 1 Parallel Pipes 18 Section 7 PCM A Frame...

Page 4: ...ts 15 Figure 5 1 Tie line 1 16 Figure 5 2 Tie line 2 16 Figure 5 3 Loop 16 Figure 5 4 Looped system 1 16 Figure 5 5 Looped system 2 16 Figure 5 6 Distributed system 17 Figure 5 7 Interpreting distributed systems 17 Figure 5 8 Poor coated steel shield 17 Figure 5 9 Perfect coating 17 Figure 6 1 Parallel Pipes Example 1 18 Figure 6 2 Example 1 interpretation 18 Figure 6 3 Parallel Pipes Example 2 18...

Page 5: ...ys measure the voltage potential of the pipe with respect to the earth around it to show that the pipe is protected against corrosion Some pipes due to coating degradation or damage have low protection voltages and are at risk of increased corrosion damage Simple Ohms law shows that adding more current will cause more voltage but higher rectifier output voltages have been shown to speed the degrad...

Page 6: ...modes that enable both distribution and transmission pipeline systems to be effectively mapped Connecting the PCM is straightforward and the transmitter s current reading LCD and power indicating LEDs help the operator to choose the best settings for the specific pipeline application For PCM Transmitter operating instructions please refer to Section 2 PCM Receiver The handheld receiver unit is use...

Page 7: ... Serial Port For service personnel only Heat sink Vents heat from the transmitter during operation Figure 2 1 Tx Facia 1 2 3 4 5 6 7 8 9 2 2 Frequency Select The LCD displays the selected 4Hz output current in amps The three position rotary switch selects the applied mapping frequencies as follows ELF Transmission Lines ELF maximum range 35 4Hz 65 ELF 128Hz or 98Hz Figure 2 2 Frequency Selector EL...

Page 8: ...r has reached its own power limit Switch to a lower current setting until the GREEN Output OK LED illuminates Allow a few seconds to settle between selections 2 6 Signal Connection Warning Appropriate safety procedures must be followed before removing pipeline CP connection Switch the PCM transmitter OFF before handling connection leads Procedure Disconnect both pipe and anode cables from the rect...

Page 9: ...ch pipeline can be surveyed individually This allows the maximum range to be surveyed Connect the white PCM transmitter lead to one of the pipeline cables and the green connection lead to the anode cable Use the PCM receiver to help identify the cables to the individual pipelines If the PCM transmitter signal is applied to more than one pipeline at a time the signal will be divided between them so...

Page 10: ...itter Using another pipeline as a ground for the PCM transmitter is an effective way of applying the signal Note Make sure that the other pipeline runs in a different direction from the pipeline being surveyed Streams drainage ditches dykes marshes or any mass of water can be used to ground the transmitter Connect the green lead to any large metal object and submerge it in the water Note Make sure...

Page 11: ...negative supply and the red lead to the positive supply and switch the receiver on If the supply cannot provide 5A this will be indicated by the power limit warning light Turn the six position Current Select switch to the minimum position and switch on the PCM Transmitter Progressively increase to obtain a current output setting which does not overload the input Maximum output power is dependent u...

Page 12: ...ent gain value Also Log file index Power Mode Indicates when Power mode selected Figure 3 1 Receiver Controls 1 2 3 4 5 6 Bar Graph Displays signal strength Fault Find 8KFF or ACVG using the Radiodetection A frame Antenna Display Narrow Peak twin horizontal antenna Null vertical antenna Battery Level Displays battery level No locate is possible at minimum zero bars Depth or Current Display Display...

Page 13: ... measurements SIGL Select either NORM or LOW NORM is sufficient for most applications Select LOW if working in poor conditions TIME Selects time for the inactivity timer and can be set to OFF 5 mins 10 mins or 20 mins 1 2 3 4 5 6 7 8 9 VIEW Allows the user to review stored log data ACCE Selects either SDDA submersible double depth antenna or STH stethoscope accessories 3 4 Batteries The LCD provid...

Page 14: ...urements the white arrow on the bottom of the magfoot should be pointing away from the transmitter Press and hold the Antenna Select key to initiate the PCM current measurement The signal strength bargraph will scroll across the screen and after 4 seconds the measurement cycle is complete The reading will remain on the display until it is saved or rejected Note Before the reading is saved or rejec...

Page 15: ...u Scroll through the menu options until DEL is displayed Momentarily press the On Off key and you will be given a choice either NO or YES To delete all stored logs use the Up Down key to select YES and momentarily press the On Off key Review Mode Saved data within the PCM can be reviewed To review stored logs carry out the following Momentarily press the On Off key to enter the menu and scroll thr...

Page 16: ...e will then be directly over the pipeline and at right angles to it Mark the pipeline position 4 3 Null Procedure Follow the procedure for pinpointing with a peak response and mark the position Switch to null response and follow the left right arrows Note the position of the null response over the target 1 2 3 4 5 6 If the positions of the peak and the null pinpoints correspond it can be assumed t...

Page 17: ...in this condition the CD arrow will point away from the transmitter 4 6 Mapping Current Measurements Obtaining and understanding results A current flowing on a buried conductive structure produces a magnetic field directly proportional to the magnitude of the applied current By resolving components of the magnetic field from above surface the original current can be precisely determined At the hea...

Page 18: ...tial mA result to logarithmic dBmA will show the same graph as a straight line slope Displaying the results using dBmA loss per distance has the advantage that the resulting graph is easier to analyse Example There was a coated pipeline which had three defects of equal electrical resistance one near the beginning the next in the middle and one at the end If the current loss graph is prepared using...

Page 19: ... by another utility line above the pipeline and should be ignored or further investigation undertaken Steps B to E show definite steps with some field distortion at the point of fault and loss of signal Note the recovered reading is less than the signal before the trouble Further investigations using the PCM A Frame should now be undertaken so as to pinpoint the exact position of the faults Figure...

Page 20: ...pipeline with the greatest reading indicates where the majority of current is flowing from and is the direction to follow in order to locate the fault short or poor coating Loops If the current arrow changes direction it could indicate the pipe has changed location Use the PCM in locate mode to relocate it Current flow within a Loop system If all distances and coatings are equal and the rate of lo...

Page 21: ... was quickly and easily detected Figure 5 6 Distributed system Figure 5 7 Interpreting distributed systems 5 2 Pipelines and Pipeline defects Interpretation of Readings and Graphs Pipe coating in good condition is shown as very little loss of current Pipe coating in poor condition is shown as a rapid loss of in current Mixture of good and poor coating which is shown as greater current loss over th...

Page 22: ... Transmitter current This is indicated by the locate being offset to one side and the rapid decrease in current reading When plotted the graph illustrated this effect with the bend indicating the position of the short or contact To verify the fault location the transmitter was repositioned to the other end of the pipeline and the following results obtained Section A Good Peak and Null locate readi...

Page 23: ...w pipeline to fall Figure 6 6 illustrates this effect Figure 6 6 Example 3 interpretation Figure 6 7 Angled Pipes Example 1 Example This example Figure 6 7 demonstrates a survey on new pipeline where the current on one side of the transmitter flowed away from the transmitter The PCM Transmitter was connected and a 1 Amp current selected A reading of 900mA was detected on one side with the arrows p...

Page 24: ...w pipeline and measurements taken at exactly the same positions A reading of 800mA was detected on the new pipe but there was no reading on the old pipeline As a series of readings were taken on both pipelines closer to the point of bonding current appeared on both pipelines and with the arrows in opposite direction This indicated that the bonding point was further ahead The point of bonding was l...

Page 25: ...e locate frequencies Position the A frame above and in line with the pipeline and the spike marked with green tag away from the transmitter connection point red spike tag towards transmitter 1 2 Figure 7 1 A Frame Fault Finding On the PCM receiver select ACVG or 8KFF using the function key the A Frame symbol will appear on the LCD Push the A Frame spikes into the ground to take a reading It will t...

Page 26: ...ximately 1 meter from the fault position testing at 25cm or smaller intervals Note the highest dB microvolt reading or save it in the datalogger and note log number During the survey you can switch to locating the pipeline by pressing the function key and selecting the appropriate locate frequency 7 4 Saving PCM FF Readings You can record and store up to one thousand A Frame results Take readings ...

Page 27: ...always be a degree of field distortion at these points Taking readings too close to large parked vehicles moving vehicles boots or shoes with steel toe caps or large metal structures Taking readings near to PCM Transmitter and anode cables or anode ground bed Measurements taken near the transmitter anode bed or earth stake can be misleading This is because all the signal current passes through the...

Page 28: ...rom the fault current settles to a steady state If this local effect is observed it is useful for detecting defects Graph C shows what would be expected in the real situation if PCM currents were plotted over a section of pipe with a coating defect Depending on the fault characteristics the effect of the magnetic field distortion will spread over a distance of perhaps 2 to 10 meters either side of...

Page 29: ...timized for larger screens but includes all the features of the PDA version including the ability to import logged data from the receiver via a USB Bluetooth dongle Radiodetection recommend using a USB Bluetooth dongle when transferring data from the PCM receiver to a PC For further information on PCM SurveyCERT and how to install PCM SurveyCERT onto your PDA or PC go to www radiodetection com pcm...

Page 30: ... keypad auto manual PCM Tx Transmitter Frequency Select Current Direction CD provides a positive identification of the out going current and provides a method of locating pipe faults using the A Frame The three position switch selects the following mapping frequencies ELF Maximum range for Current Logging 4Hz 98Hz 128Hz ELCD Standard Current Logging with CD 4Hz 8Hz CD 98 128Hz LFCD Improved depth ...

Page 31: ...M Operation Manual 27 PCM Attachment A frame A frame for detection of sheath faults on buried pipes and cables Includes PCM connection cable Weight 1 55kg 3 4lb Size 8 5 x 59 x 4 5cm 33 x 39 3 x 1 7 inch ...