Westermo RM-240 Reference Manual

Wireless ethernet radio modem

Hide thumbs

Table of Contents

Quick Links

Reference Guide

6193-5201

RM-240

Wireless Ethernet

Radio Modem

www.westermo.com

Table of Contents

Need help?

Do you have a question about the RM-240 and is the answer not in the manual?

Questions and answers

Summary of Contents for Westermo RM-240

Page 1 Reference Guide 6193-5201 RM-240 Wireless Ethernet Radio Modem www.westermo.com...
Page 2 Thank you for your selection of the RM-240 Wireless Ethernet Modem. We trust it will give you many years of valuable service. 6193-5201...
Page 3 ATTENTION! Incorrect termination of supply wires may cause internal damage and will void warranty. To ensure your RM-240 enjoys a long life, double check ALL your connections with the users manual before turning the power on. Caution! For continued protection against risk of fire, replace the internal module fuse only with the same type and rating.
Page 4: Important Notice
Like all industrial electronic prod- ucts, WESTERMO products can fail in a variety of modes due to misuse, age, or mal- function. We recommend that users and designers design systems using design tech-...
Page 5: Chapter One Introduction
Please check with your WESTERMO representative for the permitted channel usage in your country. The RM-240 unit also provides two serial connections as well as the Ethernet connec- tions. It is possible to use all three data connections concurrently, allowing the RM-240 to act as a Device Server.
Page 6: Network Topology
1.1 Network Topology The RM-240 is an Ethernet device, and must be configured as part of an Ethernet net- work. Each RM-240 must be configured as: … an “Access Point” or a “Client”, and … a “Bridge” or a “Router”.
Page 7 An Access Point could be used as a “Repeater” unit to connect two RM-240 Clients which do not have direct reliable radio paths. Multiple Access Points can be set-up in a “mesh” network to provide multiple repeaters. Bridge vs Router...
Page 8: Getting Started Quickly
… Set the RM-240 address settings as per section 3.4 … Save the configuration – the RM-240 is now ready to use. Before installing the RM-240, bench test the system. It is a lot easier to locate problems when the equipment is all together.
Page 9: Antenna Installation
Obstructions which are close to either antenna will have more of a block- ing affect than obstructions in the middle of the radio path. The RM-240 modules pro- vide a diagnostic feature which displays the radio signal strength of transmissions (refer Diagnostics section).
Page 10: Plant And Factory Installations
Where it is not possible to achieve reliable communications between two RM-240 mod- ules, then a third RM-240 module may be used to receive the message and re-transmit it. This module is referred to as a repeater. This module may also have a host device con- nected to it.
Page 11: Installation Tips
The gains and losses of typical antennas are Antenna Gain (dBi) Dipole Collinear 5 or 8 Directional 10 – 28 Cable type Loss (dB per 10 m / 30 ft) RG58 Cellfoil RG213 LDF4-50 -1.5 The net gain of the antenna/cable configuration is determined by adding the antenna gain and the cable loss.
Page 12 2.2.1 Dipole and Collinear antennas. A dipole or collinear antenna transmits the same amount of radio power in all directions – as such that are easy to install and use. The dipole antenna with integral 5 metres (15 feet) cable does not require any additional coaxial cable, however a cable must be used with the collinear antennas.
Page 13 2.2.2 Directional antennas. Directional antennas can be … a Yagi antenna with a main beam and orthogonal elements, or … a directional radome, which is cylindrical in shape, or … a parabolic antenna. A directional antenna provides high gain in the forward direction, but lower gain in other directions.
Page 14: Serial Connections
2.3 Power Supply The RM-240 module can be powered from a 9 – 30VDC power supply. The power sup- ply should be rated at 1 Amp. The positive side of the supply must not be connected to earth. The supply negative is connected to the unit case internally. The DC supply may be a floating supply or negatively grounded.
Page 15: Rs485 Serial Port
Ring indicator – 2.4.2 RS-485 Serial Port The RS-485 port provides for communication between the RM-240 unit and its host device using a multi-drop cable. Up to 32 devices may be connected in each multi-drop network. As the RS-485 communication medium is shared, only one of the units on the RS-485 cable may send data at any one time.
Page 16 100M LINK RS-485 RMINATION SETUP ETHERNET RS-232 (MDI X) (DCE) RS-485 POWER 6193-5201...
Page 17: Discrete (Digital) Input/Output
2.5 Discrete (Digital) Input/Output The RM-240 has one on-board discrete/digital I/O channel. This channel can act as either a discrete input or discrete output. It can be monitored, or set remotely, or alternatively used to output a communications alarm status.
Page 18: Chapter Three Operation
Chapter Three OPERATION 3.1 Start-up “Access Point” Start-up An Access Point unit starts and immediately begins transmitting periodic messages called beacons. These beacon messages are messages contain information for Clients on how to establish a link with the Access Point. Any Client that hears the messages, which are not already linked to another Access Point unit, will respond and links will be established between the new Access Point and these Clients.
Page 19: Led Indication
How a Link connection is lost The Access Point refreshes the link status with a Client every time a message is received from that Client. If nothing is received from a Client for a period of 120 seconds, the Access Point sends a “link-check” message. If there is no response to the link-check a De-authenticate message is sent and the link is dropped.
Page 20: Selecting A Channel
3.2 Selecting a Channel The RM-240 conforms to the IEEE 802.11 Wireless LAN specification. The RM-240 sup- ports 11 radio channels, each 5MHz wide, in the range 2412MHz to 2462MHz. Only one of these channels is used for a connection. The desired channel is selected and config- ured at the Access Point, and is then used for all beacon transmissions and connections.
Page 21: Default Configuration
Ethernet address for the RM-240 is 192.168.0.1XX where XX are the last two digits of the serial number (check the label on the back of the module). The second method requires setting an IP address in the RM-240 such that it is acces- sible on your network without having to change your network settings.
Page 22 Switch Factory Default dip-switch on RM-240 to SETUP position. b) Connect the RS232 port on the RM-240 to the RS232 port on the PC using a “straight-through” serial cable. c) Open a terminal package (such as Hyperterminal) with 19.2 kbit/s data rate, 8 data bit, 1 stop, no parity and no flow control.
Page 23: Network Configuration
Ethernet device(s) – before connecting to an existing LAN consult the network administrator. A system of RM-240’s must have at least one Access Point acting as a master to one or more Clients. All RM-240’s to be configured as part of the same wireless network should be given the same System Address (SSID) and Radio Encryption settings.
Page 24 Factory. For the majority of systems, this item should not be changed. If the device is to be connected to equipment that will only communicate with a set MAC Address, the RM-240 may clone that MAC address. Gateway IP Address This is only required if the wired LAN has a Gateway unit which connects to devices beyond the LAN –...
Page 25 WEP Encryption is selected. These keys should be the same for all RM-240 units in the same system. One of the four keys may be selected as the default key, and is used to encrypt transmitted messages from the config- ured unit.
Page 26: Ethernet Data
Address mode configuration can be altered via the Repeaters configuration page. When 3-address mode is used it is not possible for a RM-240 client to transmit over the radio link the MAC address of any device connected to its wired Ethernet port.
Page 27 Therefore, the RM-240 client must act as a proxy for devices lying on its wired Ethernet port, and use its own MAC address on their behalf. To do this, it analyzes the IP addresses within the Ethernet frame body and builds a lookup table so that when radio traffic is received it can lookup the device MAC address based on its IP address.
Page 28: Radio Configuration
If subsequent transmissions are successful at the lower rate, the RM-240 will attempt to increase to the next highest rate when probation has ended. This can occur when either a specified number of data frames have been successfully transmitted at the lower rate, or when a specified amount of time has elapsed whilst using the lower rate.
Page 29 Fallback Probation Counter When one of the fallback data rates is selected, the radio data rate may be upgraded to the next highest rate after this many consecutive successful transmis- sions. The default value is 10. Fallback Probation Timer When one of the fallback data rates is selected, the radio data rate may be upgraded to the next highest rate after this amount of time is spent at a lower rate.
Page 30 Bridge Priority of 32768 by default. The intention is to reduce traffic that the RM-240 must handle, by placing it at the branch level in the network tree. As a branch, the RM-240 needs only pass traffic to devices that are its “leaves”.
Page 31 WDS Access Points require IEEE802.11 4-address mode. 4-address mode may also be used by RM-240 clients when Ethernet protocols other than IP are to be used – see sec- tion “3.7 Normal Operation” for more details. Each RM-240 Access Point supports up to 6 separate interfaces for WDS links to other Access Points.
Page 32 not require IP address configuration (they inherit the IP address of the standard wireless interface), they can be configured to automatically connect to other WDS enabled Access Points. A WDS router interface allows traffic to be routed to an Access Point on a different network, and therefore requires configuration of an IP address to reflect the network address of the destination network.
Page 33 are four WDS Access points each with the possibility of having their own client/stations associated. In both examples A, B, C, and D can all exchange data with each other. The bridged example has the advantage of redundancy but at the expense of extra overhead. The routed example below cannot provide the redundancy of the bridged example, and requires more configuration effort, but does not have the overhead of using the bridge Spanning Tree Protocol, so is suited to fixed installations that do not require redundancy.
Page 34 WDS Router IP address that unit A has been configured with for its WDS link to unit B). So, this routing rule effectively tells the RM-240 that any traffic destined for the network 192.168.0.x should be forwarded to unit A via the WDS link. Units A and C would also require similar pairs of routing rules to direct traffic to the network addresses at the end points of their respective WDS links.
Page 35 Only attempt to establish WDS links with Access Points identified in the list. Maximum WDS connections Each RM-240 Access Point supports a maximum of 6 to this device WDS links direct to other Access Points. However the maximum may be reduced – this can be useful when Auto Connect is used.
Page 36 3.11 Routing Rules When a RM-240 receives an IP frame that is destined for an IP address on a different network, it checks if the network address matches the network address of one of its own interfaces (i.e. hard wired Ethernet, or wireless Ethernet, or WDS) and forwards the frame appropriately.
Page 37 When configured as a Bridge, the RM-240 will transmit all broadcast messages appearing at its wired Ethernet port. When the RM-240 is configured as a Router, this does not occur. In many cases, the intended recipient of the broadcast traffic does not lie at the opposite end of a proposed radio link.
Page 38 240 Client will act as a MAC Address translator, as it acts as a MAC address proxy on behalf of devices connected to its wired Ethernet port. Addition of RM-240 Client MAC addresses into intermediate RM-240 units’ whitelist filters may be required for correct operation.
Page 39 PPP server, Serial Gateway, and Modbus TCP to RTU server. 3.13.1 RS-232 PPP Server The RM-240 can be used as a PPP Server to connect the wireless Ethernet system to serial devices via the RS232 or RS485 serial ports.
Page 40 IP addresses in the “LMHOSTS” file on your PC. When in SETUP mode, the RM-240 PPP server is enabled. This may also be used to con- figure the module. Settings whilst in SETUP mode are as follows: …...
Page 41 TCP/IP socket for availability on an Ethernet net- work. Conversely, data encapsulated in a TCP/IP socket can be reproduced at a RM-240 serial port. Both RM-240 serial ports and the hard wired Ethernet port can be in use at the same time.
Page 42 PC. This virtual serial port can be configured to con- nect to a RM-240 serial port. Standard programs can then be used to access this serial port as if it were actually connected to the PC. Alternatively the program telnet may be used to connect to a serial port on the RM-240.
Page 43 The above example demonstrates how a Modbus/TCP Client (Master) can connect to one or more Modbus RTU (i.e serial) Slaves. In this example the RM-240 Access Point is configured with the “RS232 Modbus/TCP to RTU Gateway” enabled. Once enabled, the gateway converts the Modbus/TCP queries received from the Master into Modbus RTU queries and forwards these over the RS232 port to the Slave.
Page 44 The Digital I/O channel can also be configured to provide a status output of the module communications. If the RM-240 disassociates from another unit (that is, there is no wire- less link), you can configure the digital output to turn ON (set) or OFF (drop).
Page 45 Ethernet application), you can view or change the configuration of a remote module via the wireless link, provided the remote module is already “linked” to the local RM-240. To perform remote configuration, connect a PC to the local module, run Internet Explorer and enter the IP address of the remote unit –...
Page 46 3.17 Configuration Examples Setting a RM-240 to Factory Default Settings Access configuration webpages of RM-240. Refer section Accessing Configuration inside a module for the first time, or Modifying an existing configuration. 1. Click on System Tools Menu Item 2. Enter username “user” and password “user”, when prompted for password.
Page 47 Perform the same configuration steps as the Access Point configuration with the follow- ing differences: … set the Ethernet and Wireless IP addresses of RM-240 to 192.168.0.201 … set the Operating Mode to Client. Ensure the same System Generator String is used and the same Radio Encryption meth- od is selected.
Page 48 Access Point Configuration … Connect straight through Ethernet cable between PC and RM-240. … Ensure configuration PC and RM-240 are setup to communicate on the same network … Set dipswitch to SETUP … Power up unit, and wait for LINK led to cease flashing.
Page 49 Set the Wireless IP address to 169.254.102.53, network mask 255.255.255.0 Click on button Save to Flash and Reset. Webpage will display that message indicating details are being written to flash. Wait for RM-240 to reboot before removing power. Extending range of a network with a Repeater hop Configure units as described in Section Extending a wired network.
Page 50 Chapter Four DIAGNOSTICS 4.1 Diagnostics Chart LED Indicator Condition Meaning GREEN Normal Operation Supply voltage too low. Radio RX GREEN flash Radio receiving data Radio TX Flash Radio Transmitting Radio LINK On when a radio communications link is established Radio LINK Communications failure or radio link not established Link Established on Ethernet port Flash...
Page 51: Diagnostic Information Available
The page also indicates whether the encryption scheme has been authorized at the Access Point. A RM-240 will fail to be authorized if the encryption keys are incorrect. The received signal strength, background noise, and radio data rate is listed for each Client or Access Point by their MAC Address.
Page 52: Testing Radio Paths
IP address for the RM-240 at first startup. This command would be written as Ping 192.168.123.123 then Enter to send the ping command. The PC will reply with an acknowledgement of your command if your RM-240 is correctly configured.
Page 53 4.4.2 IPCONFIG IPCONFIG can be used to show your current TCP/IP information, including your address, DNS server addresses, adapter type and so on. In the above example ipconfig was entered in the command prompt. The reply back shows the PC’s IP address, Subnet mask and the gateway it is connected to. Other ipconfig commands will return back more information.
Page 54 RM-240 refer to Section 1.1 The RM-240 can only accept 1 Routing table. That is it can only accept one router per network of radios. On the Router radio network PC a routing rule needs to entered to allow access between Network A and Network B.
Page 55: Specifications
Chapter Five SPECIFICATIONS General EMC specification EN 300 683 FCC Part 90 Radio specification EN 300 328 FCC Part 15.247, RSS 210 Housing 114 x 140 x 30mm Plastic housing 4.5 x 5.5 x 1.2 inch DIN rail mount Terminal blocks Removable Suitable for 12 gauge (2.5sqmm) conductors...
Page 56: Firmware Upgrade
9. Switch dip-switch on RM-240 to SETUP mode. 10. Click on Upgrade button in FlashUpdate program. 11. Click OK. 12. Power up RM-240, or cycle power to RM-240, within 30 seconds of completing the previous step. 13. Programming will commence.
Page 57: Appendix B Glossary
Appendix B GLOSSARY Acknowledgment. Access point An access point is the connection that ties wireless communica- tion devices into a network. Also known as a base station, the access point is usually connected to a wired network. Antenna Gain Antennae don’t increase the transmission power, but focus the signal more.
Page 58 CSMA/CD A method of managing traffic and reducing noise on an Ethernet network. A network device transmits data after detecting that a channel is available. However, if two devices transmit data simul- taneously, the sending devices detect a collision and retransmit after a random time delay.
Page 59 The international unit for measuring frequency, equivalent to the older unit of cycles per second. One megahertz (MHz) is one million hertz. One gigahertz (GHz) is one billion hertz. The standard US electrical power frequency is 60 Hz, the AM broad- cast radio frequency band is 535 –...
Page 60 IPX-SPX IPX, short for Internetwork Packet Exchange, a networking protocol used by the Novell NetWare operating systems. Like UDP/IP, IPX is a datagram protocol used for connectionless communications. Higher-level protocols, such as SPX and NCP, are used for additional error recovery services. Sequenced Packet Exchange, SPX, a transport layer protocol (layer 4 of the OSI Model) used in Novell Netware networks.
Page 61 MAC Address A MAC address, short for Media Access Control address, is a unique code assigned to most forms of networking hardware. The address is permanently assigned to the hardware, so limiting a wireless network’s access to hardware (such as wireless cards) is a security feature employed by closed wireless networks.
Page 62 Commonly used encryption scheme used by many online retail and banking sites to protect the financial integrity of transac- tions. When an SSL session begins, the server sends its public key to the browser. The browser then sends a randomly gener- ated secret key back to the server in order to have a secret key exchange for that session Subnetwork or...
Page 63 A type of technology designed to increase the security of infor- mation transferred over the Internet. VPN can work with either wired or wireless networks, as well as with dial-up connec- tions over POTS. VPN creates a private encrypted tunnel from the end user’s computer, through the local wireless network, through the Internet, all the way to the corporate servers and database.
Page 64 E-mail : infos@westermo.fr E-mail: contact@ontimenet.com Westermo Data Communications Ltd Talisman Business Centre • Duncan Road Park Gate, Southampton • SO31 7GA Phone: +44(0)1489 580-585 • Fax.:+44(0)1489 580586 E-Mail: sales@westermo.co.uk Westermo Teleindustri AB have distributors in several countries, contact us for further information.