
Chapter 1
Osmo1 overview
14
Osmo1
™
Single-Sample Micro-Osmometer Service Guide
Thermal Printer
Power Supply &
Controls Assembly
Osmometer Module
Display Assembly
110–240 VAC
50/60 Hz
Figure 3: Mechanical components of Osmo1
1.4 Electrical description
This section describes the major electrical components
in the Osmo1 (Figure 4 on page 15).
Power supply & control PCB assembly (p/n 133028)
The power supply & control PCB assembly is divided into
lower and upper sections using a metal shelf.
•
The lower section contains the power entry module
(PEM), a 200W AC/DC power supply, and a fan. All
high-voltage connections are contained in the lower
section, making it safe to operate the instrument with
either the rear door and/or cover removed.
•
The upper section contains the control PCB
(p/n 133037PC). This board controls all of the
instrument’s low-level, time-sensitive operations, such
as the thermo-electric chamber, solenoid, thermal
printer, barcode scanner, and high-precision
temperature probes. The control board uses the
PIC32MZ microchip micro-controller.
Barcode scanner port
This port communicates to a 2D barcode scanner
(Diamond Technologies DSE0450-DTC0E) via 115 Kbps,
1 start bit, 1 stop bit, and no parity protocol. The
scanner’s presentation mode activates when an object
trips the scanner’s proximity sensor. The sensor has
built-in red illumination LEDs to help read barcodes in
low light conditions.
Thermal printer port
This port communicates to a thermal printer module
(Seiko DPU-D3-00A-E) via 115 Kbps, 1 start bit, 1 stop bit,
and no parity protocol.
RS-232 driver circuits
The instrument uses three RS-232 ports:
•
Communication to display PCB
•
Communication to scanner
•
Communication to printer
A transceiver IC handles the level translation of all three
ports.
Sample cooling assembly circuits
The sample cooling assembly circuit PCB controls the
following:
•
TEC cooling block
•
Two fans used to exhaust air from the power box and
remove heat from the TEC module
•
Activation of the solenoid for sample nucleation
•
A/D readings of the Wheatstone bridge circuits of the
sample probe and block probe
Display assembly (p/n 133022)
The display assembly functions as the main user
interface controller and provides connectivity to the USB
and Ethernet peripherals. It contains the display PCB and
color LCD screen, resistive touch element, and the USB/
Ethernet extension cables. The assembly is secured
underneath the top of the instrument’s bezel cover.
7" Color/touch LCD screen
The Osmo1 instrument has a 7" WVGA (800 x 480)
LCD/touch screen built into the display assembly. It uses
a metal gasket to reduce radiated electrical emissions.
The LCD screen has a built-in four-wire resistive touch
screen overlay.