If you think about your project technical future, then network is a logical solution for any single scale system. This article describes how to organize a network of several 7XX Indicators, how to connect and install them and what you should do if you have some problems with settings and connections of these indicators. The whole information is based on the author's personal experience got while providing a support of already existing systems and also on taking into account all the best known hardware and software problems whatever possible at any plant. After having been collected and carefully analyzed, the resulting present material is offered to everybody interested in.

Overview

The experience of getting connected a single 7XX Indicator to a PC has inspired the idea of having more than one indicator to be connected and operated by a PC simultaneously. The simplicity of making all settings and connections gives customers a chance to expand their configurations quite easily by adding a new extra indicator anytime.

Terms Used Some technical terms used in the article mean the following: Server - Personal Computer (PC) running Windows Operation System Workstation - any 7XX indicator TCP - Transport Control Protocol UDP - User Datagram Protocol IP Address - Internet Protocol Address, a unique address in a local network system Port - numeric number of addressed register where data is sent or received Expanding Protocols TCPIP

As mentioned above, TCP stands for Transmission Control Protocol thanks to which one computer sends the connection data directly to another computer intended to be sent the data to, and both computers do not lose connection during the transferring process. With this method, the two computers can guarantee that the data has arrived safely and properly, and after that the computers are disconnected. This method of transferring data tends to be quicker and more reliable, but it increases the computer's working tasks as it has to monitor the connection mentioned and the data going through it. A real life comparison to this method would be to pick up the phone and call a friend. You have a conversation and when it is over, you both hang up, releasing the connection.

UDP

As mentioned above, UDP stands for User Datagram Protocol thanks to which the sending computer sends the data packages of information as a nice little package and releases it into the network with hope that it will get to the right place. That means UDP is not connected directly to the receiving computer like TCP does, but rather sends the data out and relies on the devices placed between the sending computer and the receiving one to transfer the data properly where it is supposed to get to. This method of transmission does not provide any guarantee that the data you send will ever reach its destination. On the other hand, this method of transmission has a very low overhead and is therefore very popular to be used for services that are not so important to work as the first trial. You can compare this method with an old postal service.
You place your mail in a mailbox and hope the postal service will deliver it to the proper location. Most of the time they do, but sometimes it gets lost along the way .

Concepts

The PC is always used as a server. The 7XX is called client or workstation. The server is always listening to any data packet to come from workstation. This request can be a 7XX request of the data from the server or some 7XX data which is going to be stored on a server. Data packets used in the network are coming and going out through the objects called ports. There are two types of such ports used in a scale network system for both server and workstation sides: incoming port and outgoing port.

Installation What do we need to have one 7XX Indicator and a PC got connected? We must have the following: Software level: PC server software 7XX module software Software capable of downloading the 7XX module into the indicator Configuration software for Nport Express (or any other serial/network converter configuration software) Hardware level: PC with running Windows OS; (From 98 ,ME,2000,NT - Windows XP preferred) PC network card 10/100 Mbit ; Network switch ; Two direct (none crossed) network cables ; 7XX Indicator ; Serial/Network converter, Nport Express DE-211 is shown as an example in this article .

Connection.

Through devices data is transmitted via cables. Connect one cable to the PC network card and the other cable end to the network switch. Then connect the second cable to the switch and the other cable end to the network converter. Now connect serial cable to the network converter (usually 25 pin connector) and the other cable end to the com port of the 7XX Indicator (9 pin connector). In most cases it is the indicator's COM2 but may be COM1. If you have a serial card installed in the indicator, it may also be COM3 (25pin) or COM4 (9pin). Look at the customer's software settings to detect what port is used for the network on the indicator.

Settings.

The server computer must have a static (fixed) IP Address. That means that the IP Address of the computer where server software is running must be used constantly. Some other configurations like, for example, DHCP (Dynamic Host Configuration Protocol) are not able to always provide the same network address for the same computer. This is because a network address is selected from some preset range of addresses and is called dynamic. If the IP Address is set to some fixed value like, for example, 192.168.1.100, then it will always remain the same. The most important reason for the server to have a fixed IP Address is because this address will be set into Nport Express configuration settings.

The IP Address must be unique in a local network. It is not allowed to have two computers both having 192.168.1.100. That is why, it is important to select an IP Address which is different from any other address in the system. If you are sure that all other computers are turned on and they are present in the network at the moment , then the easiest way to check if this particular address is available is to ping this address. You may do this from any computer in the local network.

Ping the Address. Just press the Windows button START, use Run, type ' cmd ' (without inverted commas!) and press Enter. You should see something like the following:

Now type 'ping 192.168.1.100' (without inverted commas!) and press Enter. If you have a 'Request timed out' message during a ping, then this IP Address does not exist in a current network and it is legal to use it for the PC server.

So , based on the example shown, later in this article we will consider the server's IP Address as 192.168.1.100. Please note that if by some reason you are not able to use this address, you may use some other address from a range 192.168.1.1 to 192.168.1.255. Set the Server's IP Address . This is an example for Windows XP operation system. Please note that under different Windows versions you may have slightly different screens. Refer to Windows Manual or on-line help to see how to change an IP Address under the system you currently need to use. The quickest way is to press Windows button START, Control Panel, Network Connections. Now double click on a Local Area Connections.
Select Properties. There appears the screen which should be very similar to the following:

Now double click on the Internet Protocol (TCP/IP). Set the settings in the fields as it is shown on the following picture:

Press OK and in some seconds the new setting will apply to your network card.
Now ping the same address again as it has been described above. You must have a reply from the address you have just set. In other words, instead of ‘Request time out', you should get:
Reply from 192.168.1.100: bytes=32 time<1ms TTL=128
Reply from 192.168.1.100: bytes=32 time<1ms TTL=128
Reply from 192.168.1.100: bytes=32 time<1ms TTL=128
Reply from 192.168.1.100: bytes=32 time<1ms TTL=128 That means the PC server's IP Address is set and accessible in the network now. Set Network Settings for Workstation. You need software called ' NPort Management Suite'.
You may download this software from the following link:
http://www.moxa.com/drivers/Nport/Driver/Windows/v3.3/dssetup.zip . Start Nport Configurator. ' There appears thefollowing screen:

Power ON Nport Express. First, RED LED will go ON and after about 10 seconds GREEN LED should become ON.
The device is ready. Select Locate Server and then Broadcast Search. Screen will be changed and show the following information:

You can see that one Nport device has been found during the search now. It has the following IP Address: 192.168.127.254. This is a default IP Address of any Nport device and it is set on a factory. If you have several Nport devices, then first you need to connect them separately and configurate each device before they all are connected together into one network in order to avoid packet collisions.

Now double click on the left side of the form (which is under selection on the picture).
You will have the following screen:

You are free to select Nport server name. It might be a good idea to select any convenient name for a workstation. Note that this is not the name of your PC server! Simply Nport device is called ‘serial server'.
Set some IP Address, for example 192.168.1.101. and before using it check if this address is available in your system as it was described earlier.
Leave the rest of the settings as they are on this page. Select OP_Mode

Select settings as it is shown on the picture and press 'More Settings' button. There are advanced settings:

Set the settings as they are shown on the picture. As we set these settings for Workstation N1, then the port 10001 becomes the INCOMING port on the PC Server settings for this workstation. Accordingly, the port 10002 becomes the OUTGOING port on the PC server settings for this workstation. We will consider these settings closer in the next chapter.
Thus, Workstation N2 will have the port 10003 as the INCOMING port and the port 10004 as the OUTGOING port.Now go to 'Serial Settings' mode.

Set all the settings as it is shown on the picture. After all has been done , press OK button to store all the settings into the Nport flash memory.
On the Set configuration form check the progress status after update. If the update has been successful, then the status will have OK message.
Please read!
One interesting problem was reported about the update. There was a FAULT message during the update when none of the original power supplies was used with Nport Express DE-211. Please always use the original power supply to avoid this flash write problem. PC Server Software Settings. UDP configurations
PC server network settings may look like the following:

Due to different versions of the basic software, PC software setup may have some additional settings. They are connected with basic part of the software and are not shown in a current example to avoid any possible confusions . After all settings have been set, press SAVE button to save the settings and CONNECT TO ALL DEVICES to be able to accept any data packets from the specified workstations.
If due to some technical reason you need to use any other IP addresses and ports, you are allowed to do that. However, it is very important to understand that you need to change digits on both ends each time accordingly. So, for example, if due to some reason you cannot use the IP Address like 192.168.1.100, then you may put any other address (similar to that) but accordingly you must also change that everywhere in the settings as described above in this article.

Files Configuration.

All settings described above are collected and saved in one configuration file . You should be able to upload this file and set your Nport device as mentioned above if those settings do not make any conflicts with your present network configuration. First upload the configuration file for Workstation1 from here .
After that select Locate Server and then Broadcast Search.
After some time, if the device has been found , select the device needed from the list if you have several devices connected.
Go to 'Configuration' , use 'Import Configuration' .
Select the folder where you have saved the file nport_settings_wrk1.txt, then press 'Open'.
In the dialog form is opened, note that you are able to make any changes if you wish before upload them into the Nport flash memory settings.
Press OK and soon after that the Nport will be restarted with the new settings imported from the file.

Support for Previous Configuration.

Some previous models of the PC server software used a single tcp port 10055. It was used to send and receive data from a single workstation.
If you have a single workstation system which you need to configure, then you may upload configuration file from here .