Shearer Position The shearer position is measured in shields. (i.e., the shearer is at shield #55) It can be supplied one of three ways: Manual Shearer Tracking The operator follows the shearer up and down the face, pressing a key to tell the system where the shearer is located. The key does not have to be pressed on every shield – typically every 5th shield is sufficient. However, this results in a choppy shearer position that doesn't move smoothly from one shield to the next and will typically trigger several shields to advance at the same time. This is inefficient use of the hydraulic system capability and will result in reduced system pressure across the face. The automated tracking systems provide a smooth position flow and typically trigger one shield at a time, occasionally activating a second shield to keep pace with the shearer. It is recommended that an automatic tracking system be used. Infrared Shearer Tracking Infrared tracking uses the internal PMC-R infrared receiver to detect the signal from the shearer-mounted infrared transmitter. This is the simplest system for automatic shearer tracking; it has no calibration issues and has proven to be reliable. The most frequent issues with infrared tracking are operator interference (i.e., standing in front of the transmitter), transmitter/receiver angles in snake areas, and excess buildup of dust on the transmitter or receivers. Because it requires only the addition of a simple IR transmitter on the shearer, IR tracking is frequently used with non-Caterpillar shearers. It is also used as a backup to serial tracking on Caterpillar shearers. Serial Shearer Tracking Serial tracking uses a data connection to pass data from the shearer to the shield controls. The shearer determines its position and passes the data to the PMC-Rs. It is more difficult to commission because it uses several data connections at the headgate. However, serial tracking provides the most accurate measurement of shearer position. It also provides the ability to implement anti-collision options and other options that require the shields and shearer to communicate to each other. Serial tracking requires an accurate and reliable tracking system within the shearer. With Caterpillar shearers, the position calculation is very reliable and provides for superior operation of the longwall. The tracking mode is chosen by switching any SRB Tracking parameter to “ON”. When SRB is not active, pressing the P-key will change the status of the tracking mode parameter that is selected. When the selected one is switched on, the others will switch to “Off”.
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Parameter “Serial Tracking” “Infrared Tracking” “Manual Tracking” © Caterpillar
