Doc.-no.: DPC200-MOD_02_EN
Issue: 08/2019
13
OPERATION
5.7 Threshold calculation
NOTICE
The device requires a minimum pressure to calculate a volume
flow.
Minimum pressure =
0.5 % of the product mesuring range
PRESSURE < 0.5 % measuring range =
Display shows
0 m
3
/h
Minimal flow:
V_min = √(0.005 x measuring range) x k
Maximal flow:
V_max = √(measuring range) x k
Exampel: Threshold calculation
The set limit value must be between minimum and maximum flow.
As reference device we choose DPC200-MOD with a measuring range of 0...1000 Pa.
The limit value calculation formula:
V = √ΔP × k
Given values:
Measuring range =
0...1000 Pa
; k-factor (k) =
116
; Limit value (V) =
1,200 m
3
/h
It follows:
ΔP= (V / k)
2
= (1,200 / 116)
2
=
107 Pa > 5 Pa = 0.5 % of the measuring range
Minimal flow:
V_min = √(0.005 x 1000) x 116 =
259 m
3
/h
Maximal flow:
V_max = √(1000) x 116 =
3,668 m
3
/h
Result:
The limit value of
1,200 m
3
/h
is between V_min and V_max and adjustable by
our
DPC200-MOD (0...1000 Pa)
.
5.8 Function description - modbus
Hardware features:
The DPC200-MOD has two connection terminals for the Modbus, which are designated A
and B. The Modbus line of the DPC200-MOD can be terminated via a further jumper. This
jumper can be plugged into two positions: terminated or not terminated. The terminating
resistor is 120 Ohm.
Termination:
A device may only be terminated, if it is at the end of a line. Termination serves to dampen
reflections of signals and the resulting harmonic oscillations.
OPERATION
Changes to the holding register are saved to the device’s eeprom.
The durability is 100000 times, and should not be exceeded.
NOTICE
