Ocean KTA-282 Manual

Modbus tcp weather station gateway

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Overview

The KTA-282 Modbus TCP Weather Station Gateway allows the easy connection of a PLC (Programmable Logic

Controller), RTU (Remote Telemetry Unit) or SCADA System to a Davis Instruments Weather Station. Using the

Modbus RTU (Binary), or Modbus TCP/IP (Ethernet) protocols, it enables a programmable controller to monitor and

carry out actions based on wind speed, wind direction, temperature and many other weather based variables.

The KTA-282 Modbus TCP Weather Station Gateway is a major upgrade to our popular GWY-141 Modbus-

VantagePro2 Gateway. It provides all the functionality of the GWY-141, with the following improvements:

Addition of Ethernet:



Allows the KTA-282 to be polled by up to three Modbus TCP/IP masters simultaneously

Provides a webpage whereby TCP/IP settings can be easily monitored and altered. Also shows

current settings, weather data, and communications statuses.

Can be interrogated over HTTP to return Modbus register values in XML format

Allows all 125 registers to be polled at once – previously limited to 30.



Supports the new LOOP 2 command in compatible devices



Vantage Vue). This provides an additional 16 packets of previously unavailable weather data.

Provides a method to setup the weather station for first use, without the need to connect it to your PC.



Notes: 1. The Weatherlink cable can be used to update the firmware of your weather station; allowing it to respond

to the loop 2 command.

Device Compatibility

The KTA-282 is compatible with the following Davis Instruments weather stations (Davis Instruments product

numbers in bold):

6152C Cabled VantagePro2



6162C Cabled VantagePro2 Plus



6152

Wireless VantagePro2



6162

Wireless VantagePro2 Plus



6153

Wireless Vantage Pro 2 Fan Aspirated



6163

Wireless Vantage Pro 2 Plus Fan Aspirated



6250

Vantage Vue



6316

Wireless Weather Envoy



6316C Cabled Weather Envoy



7/05/2013

KTA-282 Modbus TCP Weather Station Gateway

 Connects a Davis VantagePro2 or Vantage Vue

to a Modbus network

 Modbus RTU over RS-485 and Modbus TCP/IP

over Ethernet compatible

 Easy Modbus TCP/IP configuration via webpage,

Modbus registers, or onboard switches

 Supports three simultaneous Modbus TCP

masters.

 Various selectable metric and imperial unit

conversions

 Compatible with new Davis firmware; provides

additional weather data

 Allows weather station configuration directly

www.oceancontrols.com.au

(VantagePro 2 firmware V1.90 or later, and

Page 1 of 25

Table of Contents

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Summary of Contents for Ocean KTA-282

Page 1  Allows weather station configuration directly Overview The KTA-282 Modbus TCP Weather Station Gateway allows the easy connection of a PLC (Programmable Logic Controller), RTU (Remote Telemetry Unit) or SCADA System to a Davis Instruments Weather Station. Using the Modbus RTU (Binary), or Modbus TCP/IP (Ethernet) protocols, it enables a programmable controller to monitor and carry out actions based on wind speed, wind direction, temperature and many other weather based variables.
Page 2: Table Of Contents
KTA-282 Modbus TCP Weather Station Gateway Contents Overview................................1 Device Compatibility............................. 1 Getting Started............................... 4 Weather Station Set Up..........................4 Configuring the KTA-282........................5 Configuring Modbus..........................6 Weather Station Data............................. 9 Loop 1 Data..............................9 Loop 2 Data.............................. 10 Functionality..............................11 Unit Conversions............................11 Weather Station Polling Period........................
Page 3: Getting Started
If you have a weather station with a screen you can follow the prompts after entering “setup” mode, otherwise the setup process can be done by connection to a PC. The KTA-282 also offers a method for setting up your weather station (by directly writing to registers), however it is designed for advanced users to alter calibration values and is not recommended for first use configuration.
Page 4: Configuring The Kta-282
Power Positive (8 to 28V DC; 100mW) Power Negative (Ground) RS-485 Data + RS-485 Data - Ground Male DE-9 Serial communications (RS-232) between KTA-282 and Weather station via WeatherLink cable RJ45 Socket Ethernet Port Open Collector Output 1 Open Collector Output 2...
Page 5: Configuring Modbus
Continue by connecting the DE-9 cable from your weather station (via the WeatherLink) to the male D9 port of the KTA-282. You should now see an accompanying green light every time the red LED flashes. This indicates the card is successfully receiving data from the weather station.
Page 6 3. The Default Gateway of the network. Set by the user. 4. A unique MAC address. Shipped preloaded by Ocean Controls. The TCP/IP port the request is being sent on. For the KTA-282, Modbus TCP/IP is on port 502, and the webserver (HTTP) is on port 80.
Page 7 Table 10: TCP/IP IP Address switches Configuration Using Webpage The KTA-282 has an inbuilt web server that can service HTTP requests on port 80. Simply point your web browser to the IP Address of the KTA-282 to retrieve this page.
Page 8: Weather Station Data
KTA-282 Modbus TCP Weather Station Gateway Each register holds one octet of the TCP/IP configuration. These can be read to view the current TCP/IP settings, or written to set the values. Once all twelve octets are manually set, the settings are committed to the gateway by writing a one to holding register 92.
Page 9: Loop 2 Data
KTA-282 Modbus TCP Weather Station Gateway Forecast Icons Forecast Rule Number Time of Sunrise HHMM Time of Sunset HHMM Wet Bulb °F Comms Status (1=OK, 0=Fault) Table 12: Loop 1 Modbus Register Listing Notes: The three hour barometer trend will show one of the following:...
Page 10: Functionality
KTA-282 Modbus TCP Weather Station Gateway raw pressure is affected by other weather events such as temperature, humidity, and elevation. The options are: Reading Barometric Reduction Method User offset Altimeter Setting NOAA Bar Reduction (for Vantage Pro 2 this is the default and cannot...
Page 11: Weather Station Polling Period
Weather Station EEPROM Write (Advanced users) Beware that some configuration values are set by Davis in the factory and should not be changed. The KTA-282 does not guard against ill-advised use of the EEPROM write command.
Page 12: Example (Bar= Command)
OK. But when it happens again, the KTA-282 will refuse the connection, because all sockets are occupied. The only way to recover is to power cycle either the KTA-282 or the Modbus Master, and manually sever the sockets. By writing a one to Holding Register 125, you are enabling manual socket severing. The KTA-282 monitors all open connections, and if there is no actual traffic on a socket for 90 seconds, that connection is artificially forced to close.
Page 13: Xml Request
In addition to Modbus TCP/IP, the gateway can also return the status of the holding registers via an XML file over HTTP (port 80). To trigger this request; send a HTTP GET query to the KTA-282’s IP Address with the register number appended after a forward slash.
Page 14 Using a web browser – with the gateway at its default address: 192.168.1.100/registers.xml Figure 4: Complete register listing HTTP request using browser Error Request If the GET request is of the wrong format or otherwise unrecognised by the KTA-282, a bad request XML is returned. 7/05/2013 www.oceancontrols.com.au...
Page 15: Open Collector Outputs (Pcb Rev 5 And Later)
Open Collector Outputs (PCB Rev 5 and later) The KTA-282 is equipped with two open collector outputs able to sink up to 300mA. These can be user configured to switch on/off at a given threshold of any weather data point. They are therefore useful as alarms, or for basic control operations.
Page 16: Kta-282 Pc Application
KTA-282 PC Application The KTA-282 can be configured using a purpose built PC application for windows (XP, Vista, 7, 8). This program is available for free download off the Ocean Controls website. Simply unzip the compressed archive and run the installer “setup”.
Page 17: Serial Switch Settings
“Clear Success Register” so that success can be confirmed after every attempted write. A failed write will cause the KTA-282 to reset (power off and back on). Writes holding registers 110 to 112 (EEPROM), 113 to 115 (BAR), and 116 (Success register).
Page 18: Troubleshooting
2. Probe the power terminals with a multimeter to ensure you are receiving the required DC voltage. 3. Plug the weather station into the KTA-282 using the DE-9 connector. Check the Rx LED next to the DE-9 connector. It should now flash green in combination with the red LED. If so, move to step 4. If not: 1.
Page 19 PC at default subnet (192.168.1.x), but not on 10.1.1.x. Check your network to ensure the KTA-282 has a unique IP address within the subnet. The best way to do this is via your router (if applicable). Otherwise you could power off the gateway, and then send a ping request to that IP address.
Page 20 KTA-282 Modbus TCP Weather Station Gateway on that subnet. On windows: 3.1. Set the TCP/IP settings of the gateway to default. 3.2. Open the Control Panel and go to network connections. 3.3. Right click on the LAN adapter and go to properties.
Page 21: Complete Holding Register Listing
KTA-282 Modbus TCP Weather Station Gateway Appendix A Complete Holding Register Listing Holding No. of Description Multiplier Units Register Registers Address 40,000+ Indicates the current 3-hour barometer trend. Packet Type , always 0 Location in the archive memory where the next data packet will be written.
Page 22 KTA-282 Modbus TCP Weather Station Gateway 0=Fault) 2Min Wind Speed 10Min Wind Gust Wind Direction for 10Min Gust degrees Dew Point °F Heat Index °F Wind Chill °F THSW Index °F Last 15Min Rain 0.01 Inches Last Hour Rain 0.01...
Page 23 Modbus Manually Sever Sockets Note: These values are the TCP/IP configuration currently loaded into memory. If TCP/IP switch 1 is set to load from switches, the KTA-282 will be on a different IP address to what is displayed. 7/05/2013 www.oceancontrols.com.au...
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