Knowledge Base

Working With The SyncBox

Setting Up Synchronization

1. Set up all the necessary connections and make sure you are able to record the signals. For example, the LED box should be visible in the camera view, you should have started a test observation in The Observer XT, etc. Set up The Observer XT for triggering the SyncBox.
2. Start an observation and, simultaneously, all external applications as External Programs in The Observer XT. During the observation The Observer XT triggers the SyncBox to send out one or more signals.
3. Stop the observation and the external applications, and import all data into The Observer XT.
4. Manually synchronize the observational and external data in order to be able to determine the difference in offset.
5. Once you know this difference in offset for a specific application, simply set this delay in The Observer XT next time you start this application from within The Observer XT simultaneously with the start of an observation. As a result, the start of the observation and the external application are now synchronous.

Triggering The SyncBox

You use The Observer XT to trigger the SyncBox to send out signals. You can set the interval between consecutive trigger pulses in The Observer XT.

Make sure the SyncBox is connected to The Observer XT PC via the COM port and the Auto on/off switch on the SyncBox is set to off.

Before You Start Triggering The SyncBox

• Make all the necessary connections and make sure the signal(s) can be recorded by the appropriate applications and devices.
• After you have made all connections you can check whether signals are sent out properly by pressing the blue Trigger button on the SyncBox.
• In The Observer XT, before you start an observation, make sure you have added all external applications as External Programs in the Observation source. This way the external applications are started when you start an observation.

Steps To Start Triggering The SyncBox

1. Make sure to close all unused programs; variable processor load may cause the delay to vary in the start-up of some applications.
2. In The Observer XT, open a SyncBox project.
3. Under Observation source, make sure you select Live Observation. You should not select DAQ settings when you want to use the SyncBox. If you do so, the SyncBox settings are grayed out.
4. Create a new observation.
5. Click View Settings on the far-right of the tool bar of the observation, then select SyncBox.
6. In the SyncBox Settings window, select the Enable SyncBox pulse box. Next, set the following:
   • Output port — Select the COM port that connects The Observer XT PC to the SyncBox. Usually this is the default COM1. However, if you use a Noldus USB-to-COM converter because you run The Observer XT on a laptop without a COM port, you should select another COM port. Selecting the correct COM port causes the SyncBox internal speaker to play back a sound (if switched on).
   • Pulse interval — Enter a value between 1 and 3600 seconds.
7. Press OK. If you carry out another action in The Observer XT after making the SyncBox settings, you need to return to step 5 to redo these settings.
8. Start the observation. As soon as the observation starts, all external applications are also started and the first trigger pulse is sent to the SyncBox. Synchronously, a trigger comment is logged in the event log in The Observer XT with the format: Pulse <Absolute Time Stamp Scoring hh:mm:ss.fff> - <Counter>.
9. Stop the observation after the required number of pulses have been sent. You can now determine the difference in offsets by manually synchronizing the observational and external data.

How Many Pulses Should I Use?

Send two trigger pulses at the start of an observation in the following case:

• You carry out a short observation (less than 60 minutes) — In this case it is unlikely that The Observer XT computer and the external computer will start running out of sync during an observation, so you only need to determine the difference in offset at the start of the observation.

You should always send at least two trigger pulses because The Observer XT sends the first trigger pulse at the start of the observation when the external application might not be ready yet to record the SyncBox signal.

Using A Series Of Trigger Pulses

Send a series of pulses in the following case:

• You carry out a long observation (more than 60 minutes) and you are not sure that the clocks on all systems are accurate — In this case you should send out a series of pulses during the observation. The pulse interval depends on a) the total duration of the observation and b) the inaccuracy of the clocks. By determining the difference in offset at the start and the end of the observation you know how much you should stretch the external data.

Example 1 — You carry out an observation of 8 hours while simultaneously acquiring physiological data. You know that the clock of one of the systems is not completely accurate but not dramatically so; you send a trigger pulse every 30 minutes. After you have imported the external data you determine the difference in offset at the start and end of the observation. The start is synchronous but at the end of the observation the external data lags behind 30 seconds; you should then re-import the data and shift the end time of the external data 30 seconds ahead.

Example 2 — You carry out an observation of 1 hour while simultaneously acquiring physiological data. You know that the clock of one of the systems is very inaccurate; you send a trigger pulse every 5 minutes. After you have imported the external data you determine the difference in offset at the start and end of the observation. The start is synchronous but at the end of the observation the external data lags behind 15 seconds; you should then re-import the data and shift the end time of the external data 15 seconds ahead.

Troubleshooting

No time-stamped trigger comments appear in my test observation.

• You did not select Enable SyncBox pulse in the SyncBox Settings window. See step 6 in the steps above.

No signals are sent out by the SyncBox.

• You made incorrect connections — redo the connections and test the signals by pressing the blue Trigger button on the SyncBox.
• You did not connect The Observer XT computer to the SyncBox — use the COM cable to make the connection.
• You selected the wrong COM port in the SyncBox Settings window — see step 6 in the steps above.
• One of the jumpers inside the SyncBox is in the wrong position — Open the SyncBox by unscrewing the two Philips screws sunk into the bottom of the SyncBox. Carefully remove the top part of the SyncBox. The two red jumpers are located between the COM port and the X-keys USB outputs. The RTS/DTR jumper should be set to DTR; the 1/2 jumper should be set to 2. To change the position of a jumper, lift the jumper using the small crevice just below the top and slide it back over two pins, moving one position.

When I start up my computer with the SyncBox connected, it almost continuously sends out signals.

• This happens when the default voltage of the RTS/DTR pin of your computer is +11 Volt. Only when you open an observation in The Observer XT and select the SyncBox is the base voltage on the RTS/DTR pin set to -11 Volt. During an observation, the SyncBox is triggered by +11 Volt pulses. The only solution is to turn off the internal speaker and to disconnect the external speakers until you open the SyncBox settings in an observation.

What do I use the Auto on/off switch for?

• When the Auto on/off switch is set to on, the SyncBox sends out a signal every approximately 30 seconds. You should preferably not use the Auto on/off switch for triggering the SyncBox but use The Observer XT instead, because its time base is more accurate.