Tempco tec-220, Instruction Manual, Page: 5 / 36

1–1 General
Tempco’s TEC-220 and TEC-920 Fuzzy Logic plus PID micro-
processor-based controllers incorporate a bright easy to read 4-
digit LED display indicating process value or set point. Fuzzy
Logic technology enables a process to reach a predetermined set
point in the shortest time with a minimum of overshoot during
power-up or external load disturbances.
The TEC-220 is a 1/32 DIN size panel mount controller. The
TEC-920 is a 1/16 DIN size panel mount controller. These units
are powered by 11–26 or 90–250 VDC/VAC 50/60 Hz supply,
incorporating a 2 Amp control relay output as a standard. The
second output can be used as a cooling control, an alarm or a
dwell timer. Either output can use a triac, 5V logic output, linear
current or linear voltage to drive an external device. There are six
types of alarms or a dwell timer that can be configured for the
second output. The units are fully programmable for PT100 RTD
and thermocouple types J, K, T, E, B, R, S, N, and L with no need
to modify the unit. The input signal is digitized by using an 18-
bit A to D converter. Its fast sampling rate allows the unit to con-
trol fast processes.
Digital communications RS-485 is available for the TEC-220 or
TEC-920. RS-232 is available for the TEC-220 only. These
options allow the units to be integrated with supervisory control
systems and software.
A programming port is available for automatic configuration,
without the need to access the keys on the front panel.
By using proprietary Fuzzy modified PID technology, the con-
trol loop will minimize overshoot and undershoot in a short time.
The following diagram is a comparison of results with and with-
out Fuzzy technology.
1
Chapter 1 Overview
High accuracy
This series is manufactured with custom
designed ASIC (Application Specific
Integrated Circuit) technology which
contains an 18-bit A to D converter for
high resolution measurement (true 0.1°F
resolution for thermocouple and RTD)
and a 15-bit D to A converter for linear
current or voltage control output. The
ASIC technology provides improved
operating performance, low cost,
enhanced reliability, and higher density.
Fast sampling rate
The sampling rate of the input A to D
converter is 5 times/second. The fast
sampling rate allows this series to control
fast processes.
Fuzzy control
The function of Fuzzy control is to adjust
PID parameters from time to time in
order to make manipulation of the output
value more flexible and adaptive to vari-
ous processes. The result is to enable a
process to reach a predetermined set
point in the shortest time with the mini-
mum of overshoot and undershoot during
power-up or external load disturbance.
Digital communication
The units are equipped with an optional
RS-485 or RS-232 interface cards to pro-
vide digital communication. By using the
twisted pair wires up to 247 units can be
connected together via RS-485 interface
to a host computer.
Programming port
A programming port can be used to con-
nect the unit to a PC for quick configura-
tion.
Auto-tune
The auto-tune function allows the user to
simplify initial setup for a new system.
An advanced algorithm is used to obtain
an optimal set of control parameters for
the process, and it can be applied either as
the process is warming up (cold start) or
when the process is in a steady state
(warm start).
Lockout protection
Depending on security requirements, one
of four lockout levels can be selected to
prevent the unit from being changed
without permission.
Bumpless transfer
Bumpless transfer allows the controller to
continue to control if the sensor breaks by
using its previous value. Hence, the
process can be controlled temporarily as
if the sensor reading is normal and con-
stant.
Soft-start ramp
The ramping function is performed dur-
ing power up as well as any time the set
point is changed. It can be ramping up or
ramping down. The process value will
reach the set point at a predetermined
constant rate.
Digital filter
A first order low pass filter with a pro-
grammable time constant is used to
improve the stability of the process value.
This is particularly useful in certain
applications where the process value is
too unstable to be read.