在数据采集器、PC与传感器之间增加了数据连接可能性
概览
MD485 是一种智能的RS-485 接口，允许PC对一个或多个数据采集器进行编址和通讯，通讯距离可多达1219 米。该接口还支持数据采集器与数据采集器之间的通讯，来自远程数据采集器的回呼，PC到打印机的通讯，以及数码相机到数据采集器的通讯连接。
优势与特点
- Compatible with most Campbell Scientific data loggers
- Can be used with a phone modem, Ethernet link, or spread spectrum radio to extend the distance between the data logger and PC
- Increases the distance allowed between a CC5MPX digital camera and a PakBus data logger
- Extends the distance between AVW200 Vibrating-Wire Interfaces for situations where wireless communication is impractical
- Internal buffering ensures that data is not lost during transmission and allows each side to operate at different baud rates
- Includes gas tubes on the RS-485 ports and a ground lug for better surge protection
- Communicates at rates up to 115.2 kbps
图像
3D/CAD 文件：
技术说明
MD485 包含3个端口（RS-232, CS I/O, RS-485），用于连接PC、数据采集器或另一个MD485。3个端口中的任意两个可以同时使用。
MD485 能够被设置成提供透明通讯、MD9 模拟和PakBus®联网。尽管MD485 能够模拟MD9，MD485 却不能够被添加到已有的MD9 网络中。PakBus 联网要求数据采集器使用PakBus 通讯协议。PC400 或 LoggerNet 软件用于初始化和控制PakBus通讯连接。
所要求的设备
MD485 到货时带有10873 线缆和SC12 线缆，用于将MD485连接到PC或数据采集器。点-点 或 点-多点 网络使用以下设备：
- 运行PC400 或 LoggerNet 软件的计算机
- 在计算机端，MD485 通过#10873线缆连接到计算机。
- 在每一个数据采集器端，MD485 可以连接到数据采集器的 CS I/O端口（不支持CR200(X)系列），或者数据采集器的RS-232 端口（不支持CR510 或 CR10X）。SC12 串口线缆连接MD485 modem到CS I/O 端口。#18663 9-针公头转9-针公头的空modem线缆连接MD485到RS-232 端口。
- CABLE2TP-L 双-双绞线的22-AWG线缆连接一个MD485到另一个MD485。 请注意：当通讯距离最长和最快数据速率时，建议使用聚乙烯绝缘线缆。
- CR200(X)系列、CR510、CR800、CR850、CR10X、CR1000或CR3000 数据采集器。
- 供电电源（如下：）
- 环境机箱。在每一个野外站点，数据采集器、供电电源和MD485都应当被安放在机箱内，如果设备不是位于建筑物内部。
给MD485供电
在计算机端通常使用交流电源，需要使用#15966 市电充电适配电源。在野外站点，MD485 可由数据采集器的CS I/O 端口供电。如果MD485连接到数据采集器的RS-232 端口，而不是CS I/O 端口，或者如果数据采集器是在1997年12月之前购买，则需要#14291 野外电源线缆。电话-MD485 和 射频电台-MD485 网络也需要带空modem端口的供电电源。使用一个A100 适配器搭配PS100 或 PS200 供电电源使用，可提供此功能。PS100 通过市电充电器或太阳能板充电。
产品规格
| Function | Permits a PC to address and communicate with one or more data loggers over a distance of up to 1,200 m. |
| Transmission Distance or Area | 1,219 m (4,000 ft) Can increase distance by using more MD485s or combining with spread-spectrum radios, Ethernet, or phone. |
| Baud Rates | 1200, 9600, 19.2k, 38.4k, 57.6k, 115.2k bps |
| Voltage | 12 Vdc (from data logger or pn 15966 wall charger) |
| Surge | Complies with IEC61000-4-5, test level 3 (±2 kV, 2 Ω coupling impedance) |
| Operating Temperature |
|
| Service Requirements | CABLE2TP two-twisted pair cables must be installed between networked data loggers and base. |
| Maximum Cable Length | 1,219 m (4,000 ft) |
| Dimensions | 15.88 x 6.35 x 1.91 cm (6.25 x 2.5 x 0.75 in.) |
| Weight | 127.6 g (4.5 oz) |
Current Drain |
|
| Standby Mode | 1.2 mA |
| Communicating | 2 to 7 mA |
Power |
|
| Standby Mode | 14.4 mW |
| Communicating | 24 to 84 mW |
ESD |
|
| Air Discharge | Complies with IEC61000-4-2, test level 4 (±15 kV) |
| Contact Discharge | Complies with IEC61000-4-2, test level 4 (±8 kV) |
兼容性
Please note: The following shows notable compatibility information. It is not a comprehensive list of all compatible products.
数据采集器
| Product | Compatible | Note |
|---|---|---|
| 21X (retired) | ||
| CR10 (retired) | ||
| CR10X (retired) | ||
| CR200X (retired) | ||
| CR206X (retired) | ||
| CR211X (retired) | ||
| CR216X (retired) | ||
| CR23X (retired) | ||
| CR295X (retired) | ||
| CR300 | Use a 18663 null modem cable. | |
| CR3000 (retired) | ||
| CR350 | Use a 18663 null modem cable. | |
| CR500 (retired) | ||
| CR5000 (retired) | ||
| CR510 (retired) | ||
| CR6 | The CR6 has integrated RS-485. | |
| CR800 (retired) | ||
| CR850 (retired) | ||
| CR9000 (retired) |
Additional Compatibility Information
Enclosure Considerations
A desiccated, non-condensing environment is required. The MD485 includes built-in keyhole flanges for mounting to the backplate of a Campbell Scientific enclosure.
Combining with Other Devices
The MD485 can be combined with our AVW200-series Vibrating Wire Interfaces, CC640 Digital Camera, Ethernet links, phone modems (including cellular), and spread spectrum radios. Field site equipment should be housed in an environmental enclosure. Information about configuring the other devices is provided in the user manuals.
Power Considerations
AC power is typically used at the computer site; a pn 15966 wall charger is required. At the field site, the MD485 is powered by the data logger through its CS I/O port. If the MD485 is connected to the data logger’s RS-232 port instead of the CS I/O port, or if the data logger was purchased before 12/97, a pn 14291 Field Power Cable is required. Phone-to-MD485 and spread spectrum radio-to-MD485 networks also require a power supply with a null modem port. An A100 adapter used with a PS150 or PS200 power supply provides this capability. The PS150 or PS200 is recharged via a wall charger or a solar panel.
下载
MD485 OS v.05 (583 KB) 06-04-2012
Current MD485 operating system. Requires the Device Configuration Utility.
Device Configuration Utility v.2.29 (54 MB) 15-11-2023
A software utility used to download operating systems and set up Campbell Scientific hardware. Also will update PakBus Graph and the Network Planner if they have been installed previously by another Campbell Scientific software package.
Supported Operating Systems:
Windows 11 or 10 (Both 32 and 64 bit)
常见问题解答
MD485: 13
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No. Isolation circuitry is not always needed, and it presents a significant increase in power consumption for battery-operated stations. For situations where external isolation modules are required, external isolation modules can be added between stations.
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Typically, only one MD485 is connected to a data logger. Sometimes two are connected to create different network segments. Technically, however, one MD485 can be connected to each data logger serial port, and up to five MD485 devices can be connected to a single data logger CS I/O port.
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256 MD485 devices can exist on a single bus. The MD485 presents ⅛ of a unit load (electrical impedance load) to the network. An RS-485 network should not exceed 32 unit loads: 256 ∙ ⅛ = 32.
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RS-485 networks should follow a bus topology whenever possible (devices daisy-chained in a linear fashion). The total amount of cable used in a single network should not exceed 1,200 m. An RS-485 repeater or a data logger with multiple MD485 devices can be used to extend the length of a network or to create more complex network topologies.
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No. The MD485 is configured to be a serial converter between two of the interfaces. The MD485 serves to convert CS I/O to RS-485, RS-232 to RS-485, or CS I/O to RS-232.
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No. The device can also be connected directly to other devices such as a computer, radio, cellular modem, serial server, or other vendor RTU. When it is not connected to a data logger, the MD485 is most commonly used to create a multidrop network behind another communications peripheral or off a computer’s serial port.
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Absolutely. The RS-485 interface of the MD485 meets the EIA/TIA-485 standards for half-duplex communications. Campbell Scientific customers have used the MD485 in conjunction with many other off-the-shelf RS-485 interfaces.
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No. The RS-485 data transceivers used in the MD485 feature fail-safe circuitry, which guarantees a logic-high receiver output when the receiver inputs are open or shorted. Because of this, biasing resistors are not needed. The transceivers also feature reduced slew-rate drivers that minimize electromagnetic interference (EMI) and reduce reflections. Because of this, termination resistors do not need to be used for most applications.
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The MD485 is compatible with nearly any serial line communications protocol. Most notably, the MD485 is regularly used for PakBus, Modbus RTU, Modbus ASCII, and DNP3.
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Transparent Communications should be used for all non-PakBus communications. It passes data from one interface to another without regard to the underlying protocol.
PakBus Networking implements a collision avoidance technique based on knowledge of the PakBus protocol. This mode should be used for PakBus communications.
案例研究
Steve Rodgers is the lab manager at the Aquaculture Research Center of the Institute of......阅读更多