How can I interface RTCM data from two LD6 units to Verify QC using a single LAN connection (Dual beam corrections)?

Note that these steps are only applicable for LD6 versions 8 or 50. If required see How do I tell which version of LD6 I have?

Where two LD6 units are installed on a vessel, they will usually be configured to receive data from different satellite beams.  For maximum reliability, users will often wish to interface the correction data from both beams to each Verify QC computer. 

Since most computers only have a single network card (and to avoid unnecessary complexity) it is best if this can be done whilst only interfacing each computer to a single LD6. This requires that both sets of corrections must be made available on each LD6.

To achieve this, two serial null-modem cables must be connected between the LD6 units and each LD6 must be configured with an external RTCM input via a spare serial port.

The LD6 units could be configured in many different ways, depending upon which other ports have previously been assigned.

In the following example, ports COM12 and COM14 are used. These are unconfigured by default and are likely to be free since most users assign the low number ports first.

Although other port numbers are equally applicable, it is suggested that these should be used, if available. Conformity will simplify troubleshooting if problems arise. Note that port COM12 is configured to duplicate the signals already available by default on COM1. This is done so that the default port remains available for other uses.

Both units should be configured as follows:

From the I/O menu, select COM14 > Next. Verify that RS232 is selected then click Next. Change the settings to 115200, 8n1 then click Next. Select Device as Solutions: In, select I/O as RTCM1 and click Next. Click Finish and click Yes for the confirmation messages.

From the I/O menu, select COM12 > Next. Verify that RS232 is selected then click Next. Change the settings to 115200, 8n1 then click Next. Select Device as Solutions: In, select Device as LBAND:LBR1, select I/O as RTCMa and click Next. Click Finish and click Yes for the confirmation messages.

Connect a null modem cable between COM14 of the Beam1 LD6 and COM12 of the Beam2 LD6.
Connect a null modem cable between COM12 of the Beam1 LD6 and COM14 of the Beam2 LD6.
This will make dual beam corrections available on both units.

The null modem cables must be supplied by the user in either of two possible forms:

a) A cable or adapter with D9 male connectors on both ends using standard RS232 null modem wiring. This cable can only be used as a coupler between two Veripos RJ45 to D9 adapter cables.

If this cable is manufactured by the user, it is only necessary to wire three pins:
 5 - 5
 2 - 3
 3 - 2

b) A cable with RJ45 connectors on both ends, wired exactly as shown below:

                           RJ45 (LD6-1)               RJ45 (LD6-2)
                                 1                              2
                                 2                              1
                                 3                              3
                                 4                              5
                                 5                              4
                                 6                              6
                                 7                              8
                                 8                              7

After configuring the units as shown above, Verify QC should be interfaced to the following ports of the LD6 unit:

            GNSS Raw data (from interfaced LD6)       -   Port 9012
            RTCMa Corrections (from interfaced LD6)   -   Port 9001
            RTCMa Corrections (from the other LD6)   -   Port 19013

Full details for interfacing Verify QC to an LD6 via the LAN are provided here.

Note: 

1. “Solutions:In” on port COM14 of the LD6 could be configured as “RTCM2” or “RTCM3” instead of RTCM1. The port number would then have to be changed:   
   
   RTCM1 – port 19013 
   RTCM2 – port 19014 
   RTCM3 – port 19015
   
   
2. In the above configuration, dual beam corrections are available to the internal LD6 position solution as well as to Verify QC. A corrected internal solution may therefore be available even if the local L-band card has lost signal. 
3. If a Factory Reset is performed, the configurations of ports COM12 and COM14 will be deleted. It will be necessary to reconfigure them, as described above.