Macurco DVP-120 User Instructions page 13

For example, to configure a unit as address "50", set switches "2, 5, 6" (see table) to ON or in the up position (01001100). See page 11
for a list of applicable addresses and dip-switch settings.
Line Termination - End of Line Resistor
The MRS-485 adapter is wired in the standard 2W-Modbus circuits definition with selectable built-in terminating resistors at the ends of
the RS-485 bus. The MRS-485 provides integral termination for end of line resistors (EOL). The MRS-485 termination uses 4-pin
connector with jumper to select termination: The user selects no termination or one of the two Modbus line termination options. The
MRS485 has two line termination options provided onboard that should cover most situations.
Place the EOL jumper on one of the following positions:
1 = 100 ohm
2 = 120 ohm
N = No termination (default)
Normal Operation
The MRS-485 will monitor the 4-20 mA current output of the detector. At power up and during its warm-up period, the 6-Series detector
will communicate its sensor type over the 4-20 current output using a custom protocol. The MRS-485 will automatically register each 6-
Series detector as it is programmed with information about all the detectors to which it can be connected. The MRS-485 will use this
information to determine the gas level sensed by the 6-Series detector by measuring the 4-20 mA current-loop output during normal
operation of the detector.
1. When the LED is solid GREEN, operation is normal, the MRS-485 knows the detector type, no errors are detected and no MODBUS
data are being received or transmitted over the RS-485 line.
2. When the LED is GREEN with random bursts of AMBER, operation is normal and now data are being received or transmitted over
the RS-485 line. The AMBER LED will come on anytime that there is data traffic.
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