FAQ: Termination
Q: How should a dome be terminated?
A: The RS485 line should be terminated with 120Ω at either end, therefore if the control end is terminated the last dome on a line should be terminated. If the control end is not terminated then two domes or two daisy chains can be connected to the same port and termination is put on the end of each line.
TM99INT/1 is terminated internally with resistor R1, which is the middle resistor above the orange plug where the RS485 is connected.
Q: A system has an MM500TXA controller, a protocol converter and two domes how should it / can it be terminated?
A: Could be terminated in two ways, the two domes could be connected in a daisy chain with the last dome terminated, or the two domes could be both be connected to the output port on the protocol converter, both be terminated and the termination removed from the protocol converter.
Q: A system has an MM500/TD8 with 6 domes connected to the RS485 bus individually how they should be terminated?
A: All the domes on the system should be terminated, the jumpers inside should be switched to unterminated if two domes are connected on the same line, if only one dome is connected to a line that line should be terminated.