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We have three 9016 Intelligent Pressure Scanners to communicate with the host computer. How can I create a connection between them?
You may use either a direct wsock32.dll function call or a winsock.ocx ActiveX control to communicate with the scanners.
Direct winsock.dll function calls. This method requires that you read the description of the windows sockets, version 1.1 or Version 2.0. The version 1.1 document may be found at: Http://support.microsoft.com/support/kb/articles/Q85/9/65.ASP
Winsock.ocx ActiveX control. This method requires that you use Microsoft Visual C++ or Visual Basic. The documentation for the Winsock control is found in the manuals of either of these programming languages.
Using the ActiveX control will allow you to open multiple connections to devices and will provide events when data is available from the TCP sockets.
The winsock.ocx ActiveX control is the easiest to implement. The ActiveX control performs less efficiently than direct calls to the wsock32.dll. The wsock32.dll function calls have a better performance, but they are more difficult to use.
What is the best way to get the highest acquiring speed from a 9016 Intelligent Pressure Scanner in a multi-module system?
The recommended method for acquiring high speed data from multiple modules uses the ?c? ?streams? command set. The ?c00? command configures a module to send data to the host computer asynchronously. The data acquisition is triggered by either an internal clock or through the use of a hardware trigger. The internal clock is not deterministic. It does not guarantee that the data will be acquired at exact time intervals. The hardware trigger is specified when the user requires that data will be acquired at exact time intervals. The trigger input on either the 90DB or any 9016 NetScanner? System scanner accepts a 0 to 5 volts square wave with a 50% duty cycle. The trigger signal may be up to 100 Hz. When using the hardware trigger, the user must set TCP backoff delays so that the communications with the host computer do not collide on the Ethernet bus. Backoff delay is set using the ?w14? command. This command is fully described in the User?s Manual. It is also necessary for the user to specify a binary output, such as format 7 or format 8 from the module in order to get the highest data rate.
What settings do I use for my second network card? (The user is planning a data acquisition system using 9016 Intelligent Pressure Scanners and National Instruments Ethernet based Fieldpoint modules. He is currently connected to his company network and would like to isolate the data acquisition hardware from the company network by using a second network card. He would like to use LabVIEW possibly with the DSC module (Bridgeview for LabVIEW.)
Install the second NIC per the manufacturers instructions. If you are going to use the factory default IP addresses in the Netscanners then you will have to select a compatible static IP address and netmask for the new NIC. A suggested (and working in my office) address is 200.253.0.1 with netmask 255.0.0.0. Windows 95 and 98 will automatically route traffic to the appropriate NIC. In NT and 2000 you must explicitly specify a routing algorithm for packets. A second alternative is to use one of the experimental class C network address ranges such as 192.168.XXX.XXX. Be aware that if you decide to use addresses other than factory default you will be required to change the addresses of the Netscanner modules before you are able to communicate with them. To do this set your computer NIC to IP address 200.253.0.1 with netmask of 255.0.0.0 and use NUSS to change the scanner IP addresses as desired. Then change the computer NIC to your desired address.
NOTE: If you are using windows NT or 2000 (I have not used XP or ME) be sure that you deselect Packet Forwarding in the NIC setup. Forwarding will allow packets onto your private network such as NetBios, Wins, or other undesirables from the company wan which will interfere (collide) with your data packets. At best these collisions will slow the throughput of your system although, if excessive, they may cause apparent software lockups. Forwarding will also allow broadcasts such as ARP, and UDP traffic to propagate onto the company wan. This may cause some difficulties with your IT department. |
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