GE Multilin D30 Line Distance Protection System 3-353 HARDWARE 3.3 DIRECT INPUT/OUTPUT COMMUNICATIONS3For the looped timing mode, the system clock is derived from the received line signal. Therefore, the timing selectionshould be in loop timing mode for connections to higher order systems.The IEEE C37.94 communications module cover removal procedure is as follows:1. With power to the relay off, remove the IEEE C37.94 module (type 76 or 77 module) as follows. Record the originallocation of the module to help ensure that the same or replacement module is inserted into the correct slot.2. Simultaneously pull the ejector/inserter clips located at the top and at the bottom of each module in order to release themodule for removal.3. Remove the module cover screw.4. Remove the top cover by sliding it towards the rear and then lift it upwards.5. Set the timing selection switches (channel 1, channel 2) to the desired timing modes (see description above).6. Replace the top cover and the cover screw.7. Re-insert the IEEE C37.94 module. Take care to ensure that the correct module type is inserted into the correct slotposition. The ejector/inserter clips located at the top and at the bottom of each module must be in the disengaged posi-tion as the module is smoothly inserted into the slot. Once the clips have cleared the raised edge of the chassis,engage the clips simultaneously. When the clips have locked into position, the module is fully inserted.Figure 3–43: IEEE C37.94 TIMING SELECTION SWITCH SETTING
