Despatch LCC/LCD2-14-4 Oven Series with Protocol 3 - Manual (Page 18)

T HEORY OF O PERATION LCC/LCD2-14 Series Oven Owner’s Manual
18 Version 1
Copyright © 2013 by Despatch Industries.
All rights reserved. No part of the contents of this manual may be reproduced, copied or transmitted in any form or by any
means including graphic, electronic, or mechanical methods or photocopying, recording, or information storage and
retrieval systems without the written permission of Despatch Industries, unless for purchaser's personal use.
3.2. The Protocol 3 Controller
The Protocol 3 is a microprocessor based digital temperature controller designed for simple and
flexible oven operation (Figure 4). The Protocol 3 controller operates as a dual-functioning
controller/High Limit instrument. The control portion utilizes a time-proportioning voltage signal
to control heating devices with minimal temperature fluctuations.
The High Limit portion protects the product and/or the oven from overheating. If the product
being processed has a critical high temperature limit, the High Limit setpoint should be set to a
temperature somewhat below the temperature at which the product could be damaged. If the
product does not have a critical high temperature limit, the High Limit setpoint should be set 5 to
15 degrees higher than the maximum programmed setpoint at which the oven will operate.
The Protocol 3 controller provides three primary operating modes:

Manual: Oven operates continuously at a fixed temperature until turned off.

Timer: Oven operates at a fixed temperature for a user-selected time period, and then
automatically turns off.

Profile: Temperatures increase or decrease as defined by 255 segments that can be allocated
to 64 ramp and soak profiles. The profiles can be linked to provide additional temperature
combinations.
Review the Protocol 3 Controller Owner’s Manual for more information.
3.3. HEPA Filters
The LCC/LCD2-14 Series ovens use HEPA (High Efficiency Particulate Air) filters to limit
particulate size in the work chamber to 0.3 microns or less. Two different types of filters are
typically used. While both filters are high-temperature filters in that they are designed for use in
thermal processing equipment, the “standard” HEPA filter is rated to 260
°C ( 500°F) while the
“high-temperature” HEPA filter is rated to 350°C (662°F).
Figure 4. Protocol 3 Operator Interface.