Description
The BPCM177 pilot cable monitor provides earth continuity protection in accordance with AS/NZS 2081, ensuring the earth connection through a trailing/reeling cable. An additional core is included with the power and earth cores which supply the remote machine. The pilot cable is connected to terminal 10 on the BPCM177 to a diode that is installed at the furthermost point of the pilot cable with its cathode connected to earth at the remote
earth connection point. The BPCM177 detects open and short circuits between the pilot and earth conductors of the trailing cable. LED’s on the BPCM177 indicate power to the unit, and if the status of the pilot cable is HEALTHY. There are two changeover contacts rated at 8A/250V which are fail-safe.
Output contacts de-energise (un-HEALTHY) on conditions of:
• Loss of power
• Open circuit of pilot cable
• Loop resistance exceeds set value.
• Leakage resistance between pilot core and earth is less than 600Ω
There are two basic operating models;
1. Automatic reset models go into a HEALTHY condition when no fail conditions exist. A stop button can be wired in series with the pilot cable to de-energise
relay if necessary. In local mode, the BPCM177 will automatically reset after the fault has been cleared.
2. Remote start or latching models have a remote 100Ω series resistor connected across a remotely mounted normally open start button. When start is pressed the BPCM177 checks loop resistance before switching to a HEALTHY condition. The BPCM177 will go into an un-HEALTHY state if the start button is held or stuck for longer than 15 seconds. In latching mode, a manual reset (press start button) is needed after the fault has been cleared.
