Technical Manual Cold Storage Controller EVP 3150-1 and EVP 3150-2
Page 12
Analogue Output
The analogue output can be used for regulation
purposes or to provide a remote display with an
actual value image. The signal is available as a
DC-Voltage or a DC-Current-Signal, fixed by "
h51
"
(Assignment Page).
Parameter "
L50
" (Actual Values Page) shows the
current output signal as a %-part of the selected
range, "
h52
" (Assignment Page) determines the
behaviour of the output:
Test functions
"h52" = "0"
output signal is 0V resp.
4 mA (fixed)
"h52" = "100
output signal is 10V resp.
20mA (fixed)
Transmission of actual values to remote displays
or similar
This function allows the analogue outputs to deliver
a mirror of measured actual value.
Normally a control probe will be used. If multiple
probes are configured, the warmest actual value will
be used. If a virtual probe is configured, this probe is
used in the same way as a real probe.
"h52" = "dIS"
The output provides an image
of the value of cooling sensor 1.
U-output:
-50°C = 0V,
+100°C = 10V
I-output:
-50°C = 4mA,
+100°C = 20mA
Control with the analog output signal (PID-control)
"h52" = "P"
PID-controller, whose output
signal represents an addition of
the components P, I, D and T1.
"h52" = "Pr"
PID-controller like above, but
with inverted output (rising
temperature = falling signal).
To adapt the controller to the process use the fol-
lowing parameters:
"
r51
" =
PID proportional band,
located symmetrically
around setpoint 1
"
r52
" =
PID-integral time (I-part)
"
r53
" =
PID-derivative time (D-part)
"
r54
" =
PID-actuator response
time (T1-part)
How to influence the analog output manually
For certain applications it may be useful to affect
the output signal manually. Any digital input can be
assigned to a function "
AnA
". Once activated, the
analogue output delivers a predefined voltage- or
current signal, e.g. to drive a valve to a specific
position.
"
h61
" or "
h62
" set to "
AnA
" (Assignment Page)
= configure digital input 1 or 2
"
r63
" (Setpoint Page)
= amount of the output in % of the selected
range, if the digital input is activated.
Example
:
Digital input OK/DI1 is configured at "
h61
" to the
value "
AnA
", "
r63
" is set to "50".
If the analogue output works as voltage output,
it delivers 5V DC. If it works as current output, it
delivers 12 mA.
Electronic Expansion Valves
with analogue input
The analogue output is able to control
expansion valves with analog input.
Therefore, "
h52
" must be set to "
EEP
".
Also in this case, "
h51
" serves as a switch
for a voltage- or current output.
PI-control, D and T1-parts de-activated
PID-control, T1-part de-activated
Control Characteristic
Actuating Variable Delay for PID
For using control processes with large reaction
times the controller offers an 'Actuating Variable
Delay'.
1. Analogue Output
If the controller sends a signal which initiates the
analogue output to rise or to fall, then an adjustable
delay time (
r56
, Setpoint Page) starts. Within this
time period, the output signal is able to alter only
by a specific %-part (step size,
r57
).
If "
r57
" is set to "100%" and "
r56
" to "0", then the
function is disabled.
2. Relay Output
In applications with motorized actuators, the
Actuating Variable Delay takes effect by clocking
the cooling resp. heating relays. If the controller
sends a signal to initiate a relay permanently ON,
an adjustable time period "
r58
" (Setpoint Page,
Cooling/Heating Relay Time Period) starts. Within
this period, the relay is engaged for the time set
by "
r59
" (Setpoint page, Cooling/Heating Relay
ON-Time).
If "
r59
" is equal to "
r58
" or exceeds it, then the
function is disabled, the relay switch as normal
again.
Reaching the The OFF-value
The OFF-value (0%) will be initiated immediately
with:
- defrost initiation
- solenoid valve lock
- safety chain error
- controller OFF
- cooling OFF with an open door
Important !!
Please note the decreased lifetime of
the relay contacts in cycling operati-
on. Please care for a suitable relief.
Cycle 40 sec.:
load current 0,8A res. --> 5 years
load current 1,2A res. --> 2,5 year
load current 1,9A res. --> 15 months
(Theoretical values according to the
relays data sheet)
r58 (s)
r59 (s)
ON
OFF
relay off
relay on
t
t
PID
integral time
I-part
P-part
5V resp. 12mA
max.
min.
proportional band
output
setpoint deviation
t
t
PID
integral time
I-part
P-part
5V resp. 12mA
max.
min.
proportional band
output
setpoint deviation
PID attack time
