Datasheet
3
263
3
▯ = ON
857-550
4 ... 20 mA
L1
DIP Switch Adjustability
DIP Switch S1
Input Signal Measuring Method Filter Output Signal
123 456
5 A Mean square value off 0 ... 20 mA
● 1 A ● Arithmetic mean value ● active
● 4 ... 20 mA
● 0 ... 10 V
● ● 2 ... 10 V
● 0 ... 10 mA
● ● 2 ... 10 mA
● ● 0 ... 5 V
● ● ● 1 ... 5 V
DIP Switch S1
Measuring Range Underfl ow Measuring Range Overfl ow
Overcurrent
(Input Signal - End Value + 20%)
Digit Output DO
Signaling
78 910
Lower limit of measuring range -5 %
*
Upper limit of measuring range +2.5 %
*
Upper limit of measuring range +5 %
*
DO not active
● Lower limit of measuring range Upper limit of measuring range +2.5 % Upper limit of measuring range +5 % ● DO U
s
+ switching
● Lower limit of measuring range Upper limit of measuring range Lower limit of measuring range ● ● DO GND switching
● ● Lower limit of measuring range Upper limit of measuring range Upper limit of measuring range
*
acc. to NAMUR NE 43
Default Setting
All DIP switches are in “OFF“ position for delivery.
Input
Input Signal 0 ... 5 A
Measuring Method Mean square value
Filter not active
Output
Output Signal 0 ... 20 mA
Measuring Range Underfl ow 0 mA
Measuring Range Overfl ow 20.5 mA
Overcurrent 21 mA
Digital Output DO not active
The digital output (DO) signals error messages and can be confi gured as follows: 24 V → 0 V/0 V → 24 V.
In order to increase the switching current of the DO, the latter may be expanded by a relay. Thanks to the contour uniformity of Series 857, for example, a 857-304
Relay can be snapped in next to it. This output can be quickly and easily expanded to a switching current of 6A by simply using an adjacent jumper (859-402).
Application example:
Digital Output DO/Signaling
Filter
The fi lter function allows a low-pass fi lter to be switched on in order to mask or “smooth out” oscillating measured values
(e.g., during trailing edge fl ows).
Switching Behavior, Digital Output (DO)
DO
%
DO‘
t
100
!
!
75
0
0
0
configured
to 75 %
Measuring
input/
Measured
value
default
! Hysteresis
PLC/
LED indication
e.g. 787-1002
16.8 ... 31.2 V
230 VAC
Current
Transformer
250 A/ 1 A
DO/
LED indication
24 V/500 mA