1. Introduction

Cable breaks or damaged cables can occur on site under numerous circumstances, including when the cable is dragged over a sharp object or the probe gets caught in the borehole and excessive pressure is applied to the cable to attempt to free the probe. However, cable breaks or damaged cables are not always clean cut or obvious to the eye. This can make cable damage difficult to spot. A damaged cable can cause intermittent communication failure between the probe and the PCB. If this occurs you will still be able to connect to the reel, but you may not be able to take readings.

2. Symptoms

Symptoms for a cable break include:

• An overstretched and misshapen cable. This would commonly look thinner and the half meter (or 2 foot) markers may not fall in the correct place because of the stretching.
  
  
• On deeper boreholes you may not be able to receive any readings from the inclinometer. Connection to the reel at the top of the borehole maybe possible. With the probe lowered into the borehole and readings are attempted, the user may receive a single 'beep' and nothing else. Commonly the user would receive a single beep followed by a double beep 'beep beep'. If the double beep is not heard this signifies that a hub was unable to communicate with the probe. No return double beep is often due to cable damage. Sometimes this syptom is intermittent. To explain why it is intermittent, it may only occur when a specific area of the cable is under tension i.e. the probe is suspended within the borehole and no longer relaxed on the reel. When the damaged point is under tension, it may cause a break in the conductors to occur.
  

• With a clean cable break or the cable completely severed you would expect when taking readings to never receive the double beep indication. 
  
  
• When in User mode in In-Port you may find on the 'Waiting for probe to stabilise' screen, In-Port may not progress past this, causing the user to have to close In-Port and restart the program.

If you believe you are experiencing these symptoms please submit a support ticket to the support requesting to return your Inclinometer for a service.

3. How to check if a cable is broken or damaged

To Further test whether there has been damage to the cable:

• Inspecting the length of the cable to see if there has been any obvious damage.
  
  
• If you are able to connect and take readings i.e. complete the beep sequence of 'Beep' pause 'Beep' 'Beep' when the cable is wrapped around the reel however when the probe is lowered you cannot take a reading then the following test can be performed to help decipher where the damage has occurred. Please raise the probe to the top of the borehole and reconnect to the probe. Then start lowering the probe into the borehole, taking readings as you normally would until the probe does not respond. Please repeat this to ensure it happens at the same point. If so then a cable break could be confirmed.
  
  
• If you are unable to progress past the 'Waiting for probe to stabilise' screen, please re-enter into In-Port and select User mode, upon setting up the reading set please ensure the stabilisation setting is Un-ticked (Figure 1.) and attempt to take readings. If you are then unable to take any readings, you hear the initial 'beep' from the reel but not the double 'beep' after, you may have a cable break. 
  

Figure 1. Ensuring to un-tick 'Wait until stable'

If you have any queries about the above information, please submit a ticket on the support site or call Soil Instruments on +44 01825 765044 for advice.

Checked MO'R v1.0 13/05/15