Created Date: 16 Feb, 2021 12:29
Last Modifed Date: 29 Nov, 2021 14:48

Using additional plugins

Harlequin Direct comes supplied with the following standard plugins:

  • Preload
  • Input
  • Screening
  • Pack
  • Tiff_Output
  • None_Output

Your workflow likely requires additional plugins specific to your print head electronics, and perhaps others for implementing features of your workflow, such as print marks.

Each plugin we supply beyond those listed above comes with an associated Technical Note, describing what the plugin does and how to configure it when used within the Direct pipeline. Please contact your technical representative for access or further assistance.

Using the heartbeat capability

Use Harlequin Direct's heartbeat capability to check an active connection, and to reconnect if a disconnection occurs. The heartbeat is configured in two parts: client-side and server-side.

Client-side configuration

The configuration of the client-side heartbeat is via the API functions hd_startHeartbeat and hd_registerDisconnectedEventHandler.

Before starting the heartbeat loop, you may wish to register a disconnected event handler that receives control if the heartbeat loop detects a disconnection. Typically, a disconnection handler attempts to reconnect to the disconnected Harlequin Direct instance.

The heartbeat loop periodically sends a heartbeat to the connected Harlequin Direct instances. If no reply is received before the next heartbeat is sent, a missed beat is recorded. If more than a specified number of consecutive heartbeats is missed, the heartbeat loop stops and raises a disconnected event. Configure the heartbeat interval (in milliseconds) and maximum number of skipped beats using the interval and maxSkipped parameters to hd_startHeartbeat, respectively.

Server-side configuration

Similarly to the client side, Harlequin Direct sends a regular heartbeat signal to clients, which detects when a disconnection occurs.

To control the heartbeat, three config options are available in the System config section:

Field nameTypeDescription
HeartbeatEnabledIntegerA boolean flag (1=true, 0=false) that indicates whether or not the heartbeat is enabled.
HeartbeatPeriodMsIntegerThe number of milliseconds between heartbeats.

How many heartbeats can be missed (that is, not responded to) before Harlequin Direct moves into a mode to accept reconnections.

Alternative input formats to HarlequinDirect

As well as taking PDF as input, Harlequin Direct supports taking input as TIFF or XML.

To use this capability, set the RipCount option in your config to 0 and ensure the Stages setting for your pipeline begins with the Preload plugin and then Input plugin.


Contone TIFF files are a supported input format.


The XML format allows images to be grouped into a job with all planes present. The attributes of the Screening tags allow different screening types to be assigned to each plane individually.

XML Format Example

<?xml version="1.0"?>
        <Plugins Input="" Output="" />
        <Plane Number="1">
                <Screening Type="" Directory="Screens\2drop_mirror_example" Screen="" NumberOfDrops=""/>
        <Plane Number="2">
                <Screening Type="" Directory="Screens\2drop_mirror_example" Screen="" NumberOfDrops=""/>
        <Plane Number="3">
                <Screening Type="" Directory="Screens\2drop_mirror_example" Screen="" NumberOfDrops=""/>
        <Plane Number="4">
                <Screening Type="" Directory="Screens\2drop_mirror_example" Screen="" NumberOfDrops=""/>