Baer DLX - Analogue Input (Signal Current Input); Summation Registers

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3.5.2 Analogue input (Signal current input)
A continuous signal current flow is applied to the signal current inputs (e.g.
0..20mA or 4..20mA). This current is proportional to the actual demand.
The method of calculation can use pulses or digital values to transmit the
data to the DLX (Main-)CPU.
Pulse: For firmware version up to 1.05.06: the signal current input (analogue input)
measures power in order to establish energy consumption. The power is
measured over short intervals, multiplied by the time and the result is sum-
mated. This sum is equivalent to the energy consumed. If the sum exceeds
a fixed limit value "W", a 25msec internal output pulse is triggered and "W"
is subtracted from the sum. "W" is designated the pulse weighting and is
set such that at maximum demand a pulse frequency of 20Hz or 16Hz
(pulse length: 25msec) is reached. The demand is measured via an exter-
nal transducer that converts the measured demand to an injected current
(selectable ranges: 0 to 20mA or 4 to 20mA).
Maximum current:
0..20mA (:=20mA)  72000 pulses per hour (:=3600sec × 20Hz)
4..20mA (:=16mA)  57600 pulses per hour (:=3600sec × 16Hz)
K 72000
DIF
=
Y
X
:20mA) .. (0 weightingvalueEnergy
×
K 57600
DIF
=
Y
X
:20mA) .. (4 weightingvalueEnergy
×
X, Y : Numerator and Divisor – no decimal places, 8 digits
K : Reading constant (for optimized reading)
DIF : Transducer range (max. value
encoder
- min. value
encoder
) := 20Hz
The reading constant "K" usually has a value of 1 (reading in kWh or kvarh).
Example: min. value: 0kW (corresponds to 0mA → 0Hz)
max. value: 3500kW (corresponds to 20mA → 20Hz)
→ Transducer range: DIFF = 3500kWh – 0kWh = 3500kWh
Reading constant: K = 1
→
144
7
720
35
= =
72000
3500
=
Y
X
: weightingvalueEnergy
Digital: For firmware version from 1.06.00 and up: the average value (50 scans per
second) will be send every second to the DLX-CPU: value 0 corresponds to
0mA (threshold: 0,1mA), value 819 corresponds to 4mA (threshold: 4,1mA),
value 4095 corresponds to 20mA. For setting of the offset (0mA or 4mA)
use the software DLXPARA.
Note: Summation of the digital values is not possible!
3.5.3 Summation registers
The weighted pulses of all inputs can be totalled in up to 4 total registers
(with positive or negative sign):
Total
i
= Σ k
n
× E
n
k
n
: sign for input n, where: k = 1 or k = 0 or k = -1
E
n
: Energy value at input n, where n = 1 … 16