INFO: How do I send a marker to an external device? [42521]

This article applies to:

E-Prime 3.0

E-Prime 2.0

Detail

The basic steps in sending a marker from E-Prime to an external device are listed below. Please refer to the linked articles for additional information regarding each step.

1. Determine how the markers values are going to be transmitted

Wired transmission can occur using Chronos, a parallel port, serial port, or a socket. The appropriate device must be added to the experiment; none of these devices are included by default. The device may also need to be configured; for example, the port address must be specified for parallel, serial, and socket devices. See the device of interest below for details on how to add and configure the device:

• DEVICE: Chronos as a Response Device [24491]
• DEVICE: Parallel Port Device [17150]
• DEVICE: Serial Device [17355]
• DEVICE: Socket Device [26069]

Wireless transmission requires LSL; see INFO: Lab Streaming Layer (LSL) [38955] for details.

NOTE: LSL can also be used in a wired Socket configuration.

2. Determine which value(s) to send

The value(s) depend on:

• the experiment design - for example, is a single marker needed to denote the onset of the stimulus? Or are multiple values needed, one for each unique stimulus condition?
• the transmission device - for example, string markers can be sent with a serial port but not with a parallel port.
• the receiving equipment and its connection to the E-Prime computer - for example, if the receiving equipment's inputs are connected to the parallel port's first two data bits, then sending a marker value of 3 sets the first two parallel port's bits high; any bits connected to the parallel port's first two data bits will then also be set high.

See INFO: Choosing a marker value to send from E-Prime to an external device [42529] for more information on which values to send.

3. Determine what method will be called to send the marker

Each wired device supports multiple event methods. For example, Chronos and the parallel port provide both individual bit-specific methods (i.e., SetBit, ResetBit) as well as multiple-bit methods (WriteInteger, WriteByte). Please refer to the article below for the device of interest for more details:

• See Section 6.5 of the Chronos Operator Manual (RELEASE INFO: Chronos Version 3.0.0.0 Released [30928]) and DEVICE: Chronos and Triggers [24492]
• DEVICE: How To Send Markers Through a Parallel Port [25286]
• DEVICE: How To Send Markers Through a Serial Port [25287]
• DEVICE: How To Send Markers Through a Socket [25288]

We recommend using Task Events which allow experiment events (such as the onset of a stimulus) to result in a task, such as sending a marker, to execute. For general information on Task Events, please refer to the following articles.

• E-STUDIO: Using Task Events [22862]
• E-STUDIO: Configuring Task Events [24789]

See Also:

INFO: How do I receive a marker in E-Prime from an external device? [42530]