External Load Controller Via Analog Input X64.1 / X64.2; Switching Thresholds / Minimum Positioning Step; Thresholds For Modulating Operation; Switching Thresholds For 2-Stage Operation - Siemens LMV37.4 Series Basic Documentation

Switching thresholds /
minimum positioning
step
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8.6 External load controller via analog input X64.1
/ X64.2
For the preselection of external outputs, an analog 4...20 mA input is provided.
Burner startup can take place only when contact X5-03/1 is closed (load controller (LR)
On / Off).
A disruption of the current input or a current signal <3mA leads to deactivation of the
analog input's external preselected output. To avoid unnecessary positioning steps of
the actuators when the input signal varies, it is possible to set a minimum positioning
step for the predefined output. The minimum positioning step only becomes active in
modulating operation. For the external load controller via the analog input, a value of 1%
is preset.
No. Parameter
123.1 Minimum output positioning step: Output external load controller analog
GND
Figure 37: External load controller via analog input X64.1 / X64.2

8.6.1 Thresholds for modulating operation

Actual value
Low-fire
Low-fire
High-fire

8.6.2 Switching thresholds for 2-stage operation

For multistage operation a hysteresis band is realized to thresholds. The hysteresis
band replaces the minimum control step for multistage operation. The bandwidth is
approx. 1 mA.
2-stage operation
Actual value
Stage 1
Hysteresis band
Stage 2
3-stage operation
Actual value
Stage 1
Hysteresis band 1
Stage 2
Hysteresis band 2
Stage 3
Basic documentation LMV37.4...
8 Connection to load controllers
LMV...
PWM fan
5
4
3
2
1
Bild 364e/0409
Current
3...4mA
4mA
20mA
Current
5mA (3...12mA)
12...13mA
15mA (13...20mA)
Current
5mA (3...7mA)
7...8mA
10mA (8...12mA)
12...13mA
15mA (13...20mA)
Display / output value
20%
20%
100%
Display / output value
P1
---
P2
Display / output value
P1
---
P2
---
P3
CC1P7546en
01.12.2009