Product Overview

© Danfoss | DCS | 2019.04
Data sheet | Superheat controller type EKE 1A, EKE 1B, EKE 1C
DKRCC.PD.RS0.A4.02 | 59
23.0 Fail safe operation In the case of sensor error, the EEV controller will go into an emergency mode ( “safe mode”),
where the valve opening degree is dened by desired OD scheme as described below.
User can read the failure status via [U118 Operation status]
Conguration Description
SH control signal fails. SH control
need Pe and S2 signal, so if one of
these signal fails, SH control based on
the actual superheat is not possible
User can via parameter [N143 SH control sensor error action) control failsafe mode]
congure the relevant option.
o Stop: valve forced closed and SH control (default)
o Fixed OD: valve at xed position (Fail safe OD), this keeps the refrigeration unit
running
o Use average OD:
• (calculated as an average of the last hour) to set a reduced OD which will be xed
during error period. This keeps the refrigeration unit running.
Conguration Description
Thermostat sensor error.
Thermostat operation needs the
signal selected in [R015 Sensor
select] to operate the thermostat
function, if this signal fails operation
based on actual temperature is not
possible
User can via parameter [N144 Thermostat sensor error action] congure the relevant
option.
o Stop: valve forced closed, Sh control and Temperature control (default)
o Fixed OD: valve at xed position (Fail safe OD). This Keeps the refrigeration running
o “Use Average”= Cutin/cutout use average on and o time to contiune cooling.
For MTR use reduced OD based average OD
• MTR: valve at 70% of average OD
Conguration Description
Thermostat sensor and SH control
sensor error, combination of the 2
above
User has no option to change the value.
Stop: valve forced closed (default)
Note:
[N138 Average OD] is calculated
during superheat control/
Temperature control is active
and stored in EEPROM. Its value
is updated every 3 hours. Reset
to factory will not delete the
calculated average values.
Parameter Function Description
N143 SH control sensor error 0 = Stop | 1 = Fixed OD | 2 = Average OD
N145
Fixed OD during
emergency cooling
if N143= 1, then dene in OD %,
Parameter Function Description
N144
Thermostat sensor
error action
0 = Stop | 1 = Fixed OD | 2 = Average OD
N145
N145 Fixed OD during
emergency cooling
if N144= 1, then dene in OD %,
SH control Failsafe mode
Thermostat Failsafe mode