EC3-33x Coldroom Controller with EX5
User Manual
EC3-33x
A.6.5.063E - Rev 4
13
Emerson Electric GmbH & Co - ALCO CONTROLS - Heerstr. 111 - D-71332 Waiblingen - Germany - Tel.: ..49 (0) 7151 509 0 - Fax: 49 (0) 7151 509 200
Thermostat Object
The thermostat object is responsible for the thermostat function. If the object is disabled the cooling/heating will be switched off and
no network variable updates will be performed. Object status information is send by the nvoStatus variable of the node object. If the
temperature alarm is disabled, the corresponding bit (“alarm_notify_disabled”) in the status structure will be set. If the thermostat is in
alarm, the corresponding bit (“in_alarm”) and additional bits like “out of limits” for high or low temperature failure, “open circuit” for
open door failure, “over range” for high temperature failure, “under range” for low temperature failure or “unable to measure” for
emergency cooling, sensor failure on both temperature sensors will be set.
Network Variables
Variable Type
Name
Type
Meaning
SNVT_temp_p
nvoAirTemp
O
Control temperature used by thermostat object
SNVT_state
nvoThermostState
O
Thermostat object status
SNVT_lev_disc
nviDayNight
I
Day / night control, ST_OFF = day operation, ST_ON = night operation
SNVT_temp_p
nvoCutoutTemp
O
Cut out temperature used by thermostat object
SNVT_temp_p
nvoCutinTemp
O
Cut in temperature used by thermostat object
SNVT_temp_p
nvoAlarmAirTemp
O
Alarm temperature used by thermostat object
SNVT_temp_p
nvoAirOutTemp
O
Air out sensor temperature
SNVT_temp_p
nvoAirInTemp
O
Air in sensor temperature
SNVT_lev_disc
nvoValve
O
Status of the valve
SNVT_lev_disc
nviCleaning
I
Cleaning control, logical ored with switch input ST_OFF = cleaning off,
ST_ON = cleaning on
SNVT_lev_disc
nviValve
I
Valve input for external control, ST_OFF = valve closed, ST_ON =
valve open
SNVT_count
nvoCycleRate
O
Number of cut in / cut out cycles during last hour
SNVT_lev_disc
nviDoor
I
Door open input, ST_OFF = door closed, ST_ON = door open
SNVT_lev_disc
nviContRun
I
Continuos operation input, ST_OFF = normal operation, ST_ON =
thermostat inhibit, continuos cooling
UNVT_THERMOST
AT
nciThermCnfg
C
Thermostat object configuration structure
The network variable from type SNVT_temp_p will have an value of 0x7FFF in case of an sensor failure or if no data was read from
the sensor input.
The network variable “nvoThermostState” is an bit field and will represent the current status on the thermostat object.
Bit No.
Description
0
0 = thermostat off, 1= thermostat on
1
0 = no cooling, 1 = cooling
2
0 = no modulating thermostat, 1 = modulating thermostat
3
0 = day operation, 1 = night operation
4
0 = alarms active, 1 = alarms inhibit
5
6
1 = High temperature alarm
7
1 = Low temperature alarm
8
1 = Door open alarm
9
0 = normal cooling, 1 = emergency cooling
10
0 = no cleaning, 1 = cleaning
11
0 = door closed, 1 = door open
12
0 = no defrost, 1 = defrost
13
0 = no operation change request, 1 = operation change request
14
1 = continues operation
