Siebe Group Company EWPX 195 Quick Start Manual

WHAT IT IS
EWPX 195(/E) is a single point tem-
perature controller designed for ap-
plications in the field of commercial
refrigeration.
The instrument provides two input
probes: one for temperature con-
trol, the other for defrost control
and speed control of the evapora-
tor's fans. Three output relays are
provided for the compressor, the
defrost system, the alarm manage-
ment, plus an output to control the
evaporator's fans through special
power modules.
HOW IT IS MADE
• Housing: plastic resin PC+ABS ex-
tinguishing grade V0
• Size: front panel 76x34 mm, depth
58 mm
• Mount: panel mount on 71x29 mm
hole
• Protection: front IP65
• Connections: on screw terminal
block for wires max 2.5 mm
wire only per block in compliance
with VDE regulations)
• Remote connection: serial con-
nection to the EWPX ECHO re-
peater (version /E only)
• Serial connection: TTL port for the
connection to the EWRS 485 inter-
face for TELEVIS system linking
• Display: 3 digit plus "-" sign; digit
height 12.5 mm
• Main outputs: 1 on N.O. relay
8(3)A 250V AC for the compressor
and 1 on N.O. relay output 5(2)A
250V AC for defrost system
• Alarm output: 1 on N.C. relay 8(3)A
250V AC
• Evaporator fans output: 1 output
to drive special power modules
• Analogue inputs: two NTC
probes, one to control tempera-
ture, the other for defrost and
evaporator fans speed
• Power supply: 12 Vac/dc ±15%
EWPX 195(/E)
controller for "forced air" refrigerating units
with evaporator fans speed control

GENERAL DESCRIPTION

EWPX 195(/E) is a single point temperature
controller designed for applications in the
field of commercial refrigeration.
The instrument provides two input probes:
one for temperature control, the other for
defrost control and speed control of the
evaporator's fans. Three output relays are
provided for the compressor, the defrost
system, the alarm management, plus an
output to control the evaporator's fans
through special power modules.
As a standard feature it can be connected
to the TELEVIS system (through its appro-
priate interface module). The "/E" version
can also be connected to the EWPX
ECHO data repeater, which allows remote
display of the temperature measured by
the instrument.
The instrument can be configured accord-
ing to the application through a series of
parameters - it is supplied in the new
32x74 mm cabinet (ELIWELL Standard).

COMMANDS ON FRONT PANEL

The instrument is provided with two keys:
"UP" and "SET/DOWN".
SET/DOWN: by pressing and releasing it
the Setpoint is displayed, the "SET" led is
turned on.
To change the Setpoint value use the "UP"
2
(one and "SET/DOWN" keys within 5 seconds.
If no operation is performed for more than
5 seconds normal mode is restored and
the new value is automatically acquired.
The same button is used to increase val-
ues during Setpoint change or parameters
programming. When held pressed a fast
increase is performed.
UP: button used for value increase, used
to change both the Setpoint and the para-
meters. A fast increase is obtained by
holding it pressed.
This key also allows manual start of the de-
frost cycle, by holding it pressed for more
than 5 seconds (this function is not en-
abled during Setpoint or parameter pro-
gramming).
During the manual defrost cycle the "DE-
FROST" led will blink.
"COMPRESSOR" Led: led related to the
compressor relay; it is on when the com-
pressor works.
"SET" Led: it is on during Setpoint display
and programming; it blinks during parame-
ter programming.
"DEF" Led: status light of the defrost. It is
on during automatic defrost; it blinks dur-
ing manual defrost.
"ALARM" Led: led related to the alarm. It
rel. 6/97 ing
is on when the alarm is active or disabled
due to the exclusion time (see parameters
"PAO", "dAo" and "tAo"); it blinks when the
alarm is silenced.
DISPLAYING AND SETTING THE
SETPOINT
To display the Setpoint value press and re-
lease "SET/DOWN"; the Setpoint value is
displayed and the "SET" led is turned on.
To change the Setpoint value operate on
keys "UP" and "SET/DOWN" within 5 sec-
onds; after such time normal mode will be
restored.
CONTROLLING THE SPEED OF THE
EVAPORATOR'S FANS
A phase choking and a filtered TRIAC al-
low the instrument to control the speed of
single-phase motors which are generally
used to operate the evaporator's fans in a
refrigerating system.
The instrument provides a probe to mea-
sure the evaporation temperature and an
output to drive special power modules di-
rectly connected to the fans (modules CF
series).
A range of parameters allows to set the
Setpoint temperature, the width of the op-
eration band and the minimum speed for
the fans of the evaporator.
The controller delivers null power for a
temperature above the Setpoint, maxi-
mum power for a temperature exceeding
the Setpoint minus the band width and a
choked power for a temperature between
the Setpoint minus the band width and the
minimum speed. After a stop the fans will
restart (at minimum speed) when the
Setpoint temperature is exceeded.
MANUAL ACTIVATION OF THE
DEFROST CYCLE
The manual activation of the defrost cycle
starts by holding the "UP" key pressed for
more than 7 seconds (the key is not active
during Setpoint or parameter program-
ming). In case the defrost conditions are
not suitable (e.g. the temperature of the
evaporator probe exceeds the end defrost
temperature) the display will show the
blinking "dFu" (deFrost unable) label.
During manual defrost the "DEFROST" led
blinks.

SILENCING THE ALARM

An alarm condition is signalled by the
"ALARM" led and the activation of the re-
lated relay on the terminal block.
The alarm can be silenced by pressing any