Macurco DVP-1200, Руководство пользователя

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Macurco TM DVP-1200 Manual
REV – 1.3.1 [34-8708-4770-7 ] 17 | P a g e
Figure 3-10 –
At 19200 baud rate (default), more than 1000 ft, and using RS-485 type cable
3.2.4.7 Wire Selection
For best performance, use shielded 3-conductor wire with one twisted pair providing a pair for signal (A & B), common (COM)
and shield ground (SHD) connections.
For the balanced pairs used in an RS485 system, wire with a characteristic impedance of higher than 100 Ohms may be
preferred, especially for 19200 and higher baud rates.
3.2.4.8 Wire Length
For the RS485-MODBUS, the wire gauge must be chosen sufficiently wide to permit the maximum length (1000 m or 3281ft). 24
AWG is always enough for the MODBUS Data. The modular RS-485 connector will accept wire from 16 to 28 AWG. The wire
insulator must be rated for at least 140°F (60°C). Category 5 cables may operate for RS485-MODBUS, to a maximum length of
600 m 1968.5 ft.
The maximum length of the trunk cable depends on the
• baud rate
• cable (gauge, capacitance or characteristic impedance)
•
number of loads on the daisy chain
• network configuration (2-wire)
For a maximum 9600 Baud Rate and 26 AWG (or wider) gauge, the maximum length is 1000m (3281ft). The derivations must be
short, never more than 20m (65.5ft). If a multi-port tap is used with n derivations, each one must respect a maximum length of
40m (131ft) divided by n.
3.2.4.9 Grounding
The Common Circuit (COM) must be connected directly to protective ground, preferably at one point only for the entire bus.
The shield should be connected to each detector at the SHD terminal and connected to a ground terminal or chassis only at one
end of the bus.
3.2.4.10 External Power Supply
Select a UL Listed NEC Class 2 power supply which can power the MRS-485 units connected to 6-Series detectors.
To determine the required minimum power supply,
• Each MRS-485 connected with a detector is rated at 3.25W.
•
The minimum power which the power supply needs to deliver for 12 detectors is figured as: 12 detectors x 3.25 W per
detector = 39W
• Therefore, a 24VDC, 60W power supply will work.
3.2.4.11 Power Wire
All field wiring is completed via modular connectors (provided). After wiring, simply plug the modular connectors into the
matching connectors on the MRS-485. The power connections to the remotely mounted detectors should be size 18 AWG
(minimum) for short runs. Since Macurco detectors are rated for operation between 12 and 24 VDC or VAC, the voltage drop