Triggering with the Leica TCS SP5, TCS SP5 II and DM6000 CFS

Communication between instruments is crucial in physiological experiments to coordinate image acquisition and physiological measurements. A common method for synchronizing imaging and electrophysiological measurement devices is the use of trigger signals. Triggering devices provide voltage signals used to generate a notification to external devices.

The trigger signal can be represented by the rising or falling edge of a voltage change, i.e., a pulse, the logic combination of two signals, or a certain level that will release a trigger signal when it falls below or exceeds. In an experimental setup, there is always a reference system. The trigger signals are named according to the reference system, which is the Leica TCS SP5. All trigger signals that leave the reference system are called trigger out signals or output triggers.

Trigger signals coming from a different instrument and going into the reference system are called trigger in signals or input triggers (Fig. 1). In most cases trigger in and trigger out signals are very short voltage changes going from 0 to 5 V. A 5 V. A trigger signal is also referred to as – a Transistor-Transistor Logic (TTL) pulse.