The Armstrong Monitoring Corporation AMC-400 Series, Руководство пользователя

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AMC-400 Series Digital Transmitter with Smart Sensor 2
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4.2.1.2 POWER SUPPLY
The AMC-400 Digital Transmitter is 24VDC powered typically either by a 120VAC AMC-1DB1-
1XXXXX Digital Monitor or a 24VDC AMC-1DB1-2XXXXX Digital Monitor.
The 120VAC AMC-1DB1-1XXXXX Digital Monitor should be used when a maximum of 1A of
current is required from its 24VDC output for MODBUS devices (transmitters, etc). The Digital
Monitor provides 4 x 24VDC power plus MODBUS channels. Each 24VDC power lane is limited
to 1A with a resettable fuse (PTC) See Figure 4-3.
The 24VDC AMC-1DB1-2XXXXX should be used when the present or future system
requirements need more than 1A for MODBUS devices. A minimum of one AMC-1DPS-7A
24VDC Power Supply is required to power both the Digital Monitor and all Transmitters. Note
that the transmitters are powered from the Power supply and
NOT the Digital Monitor. See
Figure 4-4. The Monitor’s 24VDC output has a DC voltage less than 24V when powered by the
24VDC power supply which is the reason why the AMC-1DPS-7A 24VDC Power Supply should
be used to provide Transmitter power for this configuration. The AMC-1DPS-7A 24VDC Power
Supply will provide 5A for the transmitters and other MODBUS devices. If this current is
exceeded an additional AMC-1DPS-7A Power Supply should be employed.
The AMC-1DPS-7A Power Supply and AMC-1DBx Monitor ability to drive a maximum number
of AMC-400’s (each representing 55 mA load for Electrochemical or 80-130mA for Catalytic) is
determined by what other devices are being driven (ex; relay cards), the AWG of wire selected,
and the length of cable being powered. If the cable length exceeds a distance that prevents the
Digital Transmitter from obtaining the minimum voltage at the V+ Test Point (as defined
in
Section 2.1.1.) then both an additional power supply and repeater would be required. See
Table
4-1
to aid in determining the maximum number of sensors that can be employed.
Caution:
For the 24VDC AMC-1DB1-2XXXXX configurations both the SGND and +24VDC outputs
from the 1DBx Monitor connectors (ex. J34-3 or J34-4) should not be used.
Table 4-1 Maximum number of sensor on a string limited by drop out voltage
Sensor Type Number of sensors vs total current
Average distance
between points
75ft 150 ft 200 ft
16AWG 18AWG 16AWG 18AWG 16AWG 18AWG
Electrochemical
400 CO/NO2
27 – 1.49A 21 – 1.16A 19 – 1.05A 15 ‐ 0.83A 16 ‐ 0.88A 13 ‐ 0.72A
Catalytic 19 ‐ 1.943A 15 ‐ 1.51A 13 ‐ 1.28A 10 – 1.1A 12 ‐ 1.16A 9 – 0.97A