A Practical Guide On How To Set Up Serial Pass Through For The SLA-1500

Transcription

1 A Practical Guide On How To Set Up Serial Pass Through For The SLA August 2014 Software Version 2.19 Copyright 2014 SightLine Applications, Inc. All Rights Reserved

2 Summary This document describes the serial pass-through idea, how to set it up and how to test it using SLA- Panel Plus. Even though it refers to SLA-1500, unless specifically mentioned otherwise - it pertains to both the SLA-1500 and the SLE Export Controls Exports of SightLine Applications, Inc. products and technical data are governed by the US Export Administration Regulations (EAR) (15 CFR parts ) administered by the US Department of Commerce. Classification of SightLine products has been defined as ECCN 4A994 for documentation and hardware/firmware, and ECCN 4D994 for licensed software. Customers acknowledge re-export responsibility and certify that their sale or distribution of SightLine products (whether incorporated into another system or otherwise) may constitute a new export and as such must be in accordance with the requirements of the EAR. FILES Additional files such as 3D models, schematics, Gerbers, etc. may be available through our FTP site for some products. Contact your Sales Engineer for more information. FTP: internal.sightlineapplications.com:9090 Username: slacustomer Password: 123sla123 Support NOTE: Password subject to change. Documentation and software downloads are available through our web site: SightLine Applications, Inc. Page 2 of 7

3 Background: The SLA-1500 (and the SLE-1500 as well) supports up to three serial pass-through connections. These enable the user to send data from the host PC to the SLA board (via Ethernet) and have the board relay the data on one of the serial ports. It also allows data received on these serial ports to be transmitted back to the host PC via the Ethernet connection. Details: What is pass-through useful for? The SLA-1500 board is usually used within a larger system comprising of several components at the very least a source for feeding video into the SLA board. While the SLA-1500 processes the video stream out of the camera, the camera itself can have independent settings such as aperture, exposure, focus, zoom, etc. which are normally controlled by the camera's own application running on a host PC for example. Other equipment components in the system might have similar applications controlling them, most often with a serial RS-232 connection to the host PC. Examples are cameras, autopilots, radios, pan and tilt turrets and more. Having the SLA-1500 in the system allows using a single physical connection (Ethernet) between the PC and the SLA board in the system, which in turn serves data to (and from) multiple components of the system via serial connections. This allows the integration of all command and control into one user interface on the PC, consolidating all connection between the PC and system to a single Ethernet connection. Connecting (up to 3) components to the SLA board is then done locally within the system. How does pass-through work? The SLA-1500 supports multiple communication channels. Among those are three serial ports and one Ethernet connection. The SLA software running on the SLA-1500 allows configuration of these ports to act together, in several different ways. To start with, let's assume the system has a host PC which connects to the SLA-1500 via an Ethernet switch. Remember that the host PC can connect to the SLA board via a serial port instead, but that is not the case we discuss here. For our purpose let's say the PC has an IP address of , and the SLA-1500 is assigned an IP of when the PC and SLA are connected, a pair of IP ports is used on each side. The default value of these ports is for communication from the PC to the board, and for communication in the other direction. So TCP\IP packets which comprise of commands to the SLA board are sent from the PC to the address :14001, and replies are sent from the SLA board to : Video packets from the SLA digital video output are sent to yet another IP port on the PC host. One of the commands that can be sent to the SLA as part of the functional interface protocol is a command to configure an SLA serial port. It tells the SLA to open that port at a certain configuration (baud rate, parity, data bits). The same command also includes another set of configuration details it tells the SLA board how that serial port is to be used once it is opened. This set of configuration details is discussed below. Configuring a serial port on the SLA The serial port on the SLA board can be used in several ways. One of the basic ways is as a connection 2014 SightLine Applications, Inc. Page 3 of 7

4 to a host PC. Systems which do not utilize the digital video output of the SLA-1500 can forgo the Ethernet connection altogether. In such a case the command and control of the SLA board can be done via a serial RS-232 connection to the PC (and video will be served over the analog output from the SLA board). This usage of the serial connection is not considered a serial pass through though, just a means to connect to the SLA board for controlling it. The other basic way to use a serial port is to associate it with a specific IP address and IP port. In this case data arriving from the IP address on that IP port is piped out on to the serial port, and incoming data on the serial port will be sent to the same IP address on a receiving IP port. Either UDP or TCP packets can be sent over the Ethernet portion of this connection. This is the most generic way to utilize the pass-through for controlling auxiliary equipment in the system, as it allows any data to go back and forth between a third party component that communicates serially and the host PC. Such equipment usually has an application running on the PC, which connects to the equipment with a serial cable (or a usb-serial cable converter). In order to connect such an application to the equipment on the PC side, a virtual serial port can be configured. It is the PC equivalent of a serial pass-through, and it can be configured with the 3 rd party software called HW Virtual Serial Port (HW-VSP) see If you are using this application to set a virtual port, there has to be a relationship between settings here and on the SLA board: The IP port you specify in the HW-VSP is that of the SLA-1500 board. The IP port you specify in the HW- VSP is the same you would call the inbound port on the SLA serial port configuration (4001 in the example below, as set using the SLA-Panel application). The Destination IP address you specify in the SLA serial port configuration setup is that of the PC. In this case you will use a TCP Pass-through protocol. Figure 1: Passthrough Settings Tab Panel Plus 2014 SightLine Applications, Inc. Page 4 of 7

5 If the component manufacturer has exposed the application programming interface (API) and you have the ability to send TCP/IP packets, you can forgo the virtual serial port setup altogether, and just send the data directly to the SLA-1500 IP address and the inbound IP port. Important notes: Remember that whenever changes are made to the serial port configuration on the SLA board, you must save them and restart the board. This can be done manually or by sending the reset command to the board (specify the board option in the reset). Note that serial port 0 (the one selected in this example) is unique in that it is the only one exposed to on SLA-1500 with the enclosure option. The additional serial ports (1 and 2) are available for OEM board users only, as they are not exposed through the enclosure. In order to work with the latter two ports (SLA-1500 AB interface board J10 pins 15&16 for port 1 and pins 1& 2 port 2 ) a voltage must be supplied to J10 pin 46. This can be 3.3vdc (available from the J9 connector, pin 10). See the latest revision of the SLA1500-AB board reference document. In some cases a UDP protocol is preferred over TCP, specifically when lost packets are not critical to the operation of the system. As mentioned earlier, the SLA-1500 supports UDP passthrough as well. The setup will be identical to the example above except for the protocol used. We call it Raw Pass-through, as there is no guarantee against lost packets. Additional types of pass-through (other than TCP and UDP) involve adding a parser on the incoming packets to the SLA These types of pass-through are not discussed in this document and are considered special case use. These are referred to as SLA Protocol or FIP and Aquarius. One more way to utilize the serial port is to send a specific command to the SLA-1500 (command pass-through, 0x3D) which includes the content the user wishes to emit on the serial port. This achieves a one-way communication only, as the data included as a payload within the command to the SLA-1500 is transmitted on the serial port, but there is no equivalent command to receive data and send it back. When utilizing more than one serial port on the SLA-1500, it is important to select a different set of IP ports for each serial port configured. Also remember that the Ethernet connection is probably also serving the control of the SLA-1500 board itself, on the default ports and 14002, so do not select these numbers as IP ports. Digital video is sent to the host PC on ports or 5004, so those should also be avoided. An example of three sets of configurations will be: input Port[0] = 4001; dest Port[0] = 4002; input Port[1] = 5001; dest Port[1] = 5002; input Port[2] = 6001; dest Port[2] = 6002; 2014 SightLine Applications, Inc. Page 5 of 7

6 Note that on some PCs a fire-wall or other system administration application might be preventing certain ports from being used. When using the SLA-Panel-Plus application (version 2.19 and up) you can test your setup of the serial pass through by sending some characters to the SLA-1500 and hooking up a scope or other device to the TX serial pins. Use the bottom of the pass-through tab that is depicted in figure 1 above for this purpose. Summary: The SLA-1500 can be configured for up to 3 independent pass-through communication channels. These are useful to pass control to and data back from auxiliary equipment on board the system, while consolidating all connections to the host PC to one single Ethernet connection. Special care must be taken when configuring these serial ports to get them to work correctly SightLine Applications, Inc. Page 6 of 7

7 Contacts SightLine Applications, Inc TH STREET HOOD RIVER, OR SightLine Applications, Inc. 524 N Tillamook Street Suite 101 Portland, OR Sales General sales@sightlineapplications.com info@sightlineapplications.com SightLine Applications, Inc. Page 7 of 7