Eliwell Televis EWCM 809/NH3/S Manual

WHAT IT IS
The EWCM 809/NH3/S is a con-
troller designed specifically for the
control of a machine room in a re-
frigeration system.
EWCM 809/NH3/S provides control
management of the compressors
(single units, multistage systems or
compressors having different pow-
er).

HOW IT IS MADE

• Housing: black ABS plastic,
72x144 mm, depth 120 mm
• Connections: quick-disconnect
screw terminal block
• Type of refrigerant: ammonia
• Suction sensor input: NTC or
4...20 mA pressure transducer
(scaleable)
• One pressurestat alarm input
• Global alarm output: relay 6(3)A
250V AC
• Controller breakdown output: re-
lay 6(3)A 250V AC
• Configurable outputs: 9 relays
outputs 6(3)A 250V AC
• Alarm inputs: 9 optoisolated in-
puts (the same voltage of the sup-
ply)
• Serial connection: RS-485 port for
connection to the Televis system
• Consumption: 6 VA
• Power supply: 12, 24, 110, 220 Vac
±10%, 50/60 Hz

PLUS PRODUCT

• Alarm circuit combined with each
compressor
• Clock to set the various operation
setpoints in various time periods
• UL approval pending
EWCM 809/NH3/S
compressors manager, model for ammonia

AVAILABLE VERSIONS

(from the 21/05/96, software n. 23)
EWCM 809/NH3/S (ammonia) with pres-
sure (4...20 mA programmable) or with
NTC temperature input probe and with se-
rial connection for connection to the TELE-
VIS system.

GENERAL FEATURES

The new EWCM 809/NH3/S is a controller
designed specifically for the control of a
machine room in a refrigeration system.
The main input comes from a 4...20 mA
pressure transducer for ammonia or from a
NTC temperature probe, while up to 9 re-
lay outputs with their digital alarm inputs
are provided for the management of the
single units, multistep compressors and
compressors having different power.
The EWCM 809/NH3/S is provided with
the management of the high and low pres-
sure alarms and the management of the
high and low pressurestat alarms.
The two programmable setpoints "normal"
and "economy", can be displayed in three
programmable units of measurement: Bar,
°C or °F. This feature which is available at
any time, and not only during the configu-
ration, makes the controller easy to use
and adaptable to the preference of the
User, the Installer or the Maintenance per-
sonnel.
A protection system executes a continu-
ous diagnosis of the controller; in the event
of a malfunction, a dedicated output is
used to transfer the control of the main re-
frigeration plant to an emergency system
which will take over until service personnel
corrects the situation.
rel. 5/98 ing

FRONT KEYPAD

"PRG" button: to have access the pro-
gramming.
"HRS" button: to display/reset the run-
ning hours of each compressor.
"MAINT" button: to display/modify the
"available" or "in service" status of each
compressor.
"SET" button: to display/modify the "nor-
mal" or the"economy" Setpoints.
"UP" button: to increase the figures.
"DOWN" button: to decrease the figures.
"MUTE" button: to silence/reset an
alarm.
"LOCK led": to dispaly the keyboard lock
function.
"ALARM" led: to display an alarm condi-
tion.
"COMPRESSOR & STAGES" leds: red
and green leds to display the output com-
pressor status.
4 DIGIT DISPLAY: it shows the input
probe value, the default unit of measure-
ment can be programmed with "dEU" pa-
rameter. As soon as an alarm occurs the
display will switch back and forth between
the probe read-out and the alarm code la-
bel.

INPUT AND OUTPUT

Alarm relay output: remote alarm, the
terminals 1 and 2 are closed when there is
an active alarm.
Safety relay output: the terminals 3 and
4 are open when an EWCM failure ap-
pears.
Pressurestat alarm input: high and low
pressurestat input alarms (terminals 5 and
6, "SEP" parameter).
Power supply: input terminals 9 and 10.
Economy set switch: to activate the