HXS10 SolStation Solar Tracking Controllers

Previously we introduced Yokogawa's HXS10 SolStation Solar Tracking Controller, and we explained that the HXS10 comes standard with a solar position algorithm (SPA) so that only the latitude, longitude, and time at the solar tracking installation is needed. Of course, accurate calculation of the sun's position requires that this information be correct.

Because solar trackers are normally used continually at the same site, the location values initially entered can be considered the correct ones for a long period of operation. However, the time must be periodically reset.

In this installment we give some examples of how to set the time on the HXS10.

Setting the Time Using the HXSS10 Software

This is how to set the time using dedicated HXSS10 software during maintenance and debugging. To set the time on a single HXS10, start the Setting Tool and click Communication > Set Dateand time from the menu. You can use the PC system clock, or enter a time manually.

Setting the Time on Multiple Units over a Network

You can also set the date and time on up to 1000 units over a network.

Start Multi Terminal Setting (figure 2) and register the IP addresses of the HXS10s in the instrument registration screen (figure 3). Once registered, all you have to do is press the Execute button in the Set Date and time group. As with setting a single unit, you can use the PC system clock, or enter a time manually. Note that when you press the Execute button it may take a few moments to send the time to all HXS10 units, but the time lag is corrected automatically.

Auto Setting via SNTP

The SNTP (Simple Network Time protocol) is a convenient method for synchronizing the time of multiple HXS10 units on the network.

The HXS10 can act both as an SNTP server or client. As an SNTP client, the HXS10 can synch its time with that of the SNTP server on the network. Inquiry start times and periods can be entered as parameters. The HXS10 can also act as the server, so that other units on the network can synchronize their times to it. In establishing parent/child relationships between HXS10s acting as servers and clients, you can synchronize multiple units without increasing the load on the original SNTP server. After starting up normally, it is convenient to have it automatically perform periodic synchronizations.

Enabling/disabling the SNTP server function, the time and period at which the SNTP client function performs synchronization, and the information that is queried can be set as parameters.

Automatic Settings Using Periodic Time Pulse Output

Some GPS and radio clocks can use periodic time pulse output, and the HXS10 can take advantage of this pulse output.

Units are set up so that the periodic time pulse is input at a predetermined time every 24 hours to the HXS10's contact input (DI). You can write an HXS10 user program such that when there is input on the DI, the time is set per the HOUR, MINUTE, and SECOND parameters.

As you can see there are several ways to set the time to accommodate the number of HXS10 units, the network configuration, and other factors. Whichever method you use, remember to set the time zone parameters (TZHOUR, TZMIN) in advance.