DESCRIPTION
2-20 20509 Issue 7 Jan 2018
Motherboard
The motherboard provides the interconnections between the PCBs in the
control system. It also carries all the input/output connections for the print
heads, data input, product detector, vacuum switch and external alarm
relay. The connections for one print head are all contained in a single "D"
connector. There are, therefore, four of these connectors on the
motherboard. Associated with each connector is a dual-in-line (DIL) switch
controlling the aspect ratio of the characters printed by the head.
Four rectifier/capacitor circuits on the motherboard, supplied from windings
on the power transformer, provide the 24V power supplies for the solenoid
drivers.
The motherboard has connections and switches that need to be set up to
match the printer system and application (see
page 4-38 and page A-8).
Product Detector
With a fixed product speed past the print head, the Macrojet 2 may be set
up to use a fixed print speed and operate with one of the following types of
detector:
• Photocell Detector (Reflective)
• Photocell Detector (Proximity)
• Inductive Proximity Detector.
Photocell detector (Reflective) uses a reflector mounted on the opposite
side of the product line. A light beam from the detector is returned by the
reflector to the photocell in the detector. The control circuits detect when
the reflected beam is broken (or restored after interruption) and generates
the print go signal. A time delay will normally still exist between detection
of the product and its arrival in the exact position required for printing. A
compensating delay is, therefore, entered as part of the input print data.
Photocell Detector (Proximity) does not use a reflector. Product detection
depends on reflection from the body of the product or when the edges of
light or dark markings on the product are detected.
The proximity detector senses metal products when they come within
range. This detector normally requires to be very close to the product. The
exact distance is usually dependent upon the material from which the
product is made.
The product detector must be positioned "up-stream" from the print head.
A time delay is necessary to allow the product to reach the print head and
the printing to be placed correctly. This is set up in the printer as the print
go delay (part of the Pocket Terminal input data).
Shaft Encoder (Optional)
With a fixed print speed, if the line speeds up, the printing will be spaced
further apart. If the line slows down, the printing will close up. This
problem is avoided by fitting a shaft encoder.
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