Scale signal
amplifier
WV157
suitable for monting in hazardous area

TÜV 01 ATEX 1694
+ Scale signal amplifier to connect directly
up to 4 weight cells (sum resistance
bigger than 85 Ω ) in hazardous area

+ Solid aluminium housing protection class
IP65

+ High Disturbance immunity through digital
signal tranceiving to batch controller
DC155
+ Power supply directly with net voltage, a
EEx i power supply is not necessary
Description

The combination of the dosing controller DC155
and the scale signal amplifier WV157 is a dosing
system which works with a scale signal in hazardous
area. The personnel starts the batch per start key
on the DC155. The growing weight of the good is
recognised by a scale (working with a strain gauge)
When the preselected weight is reached the DC155
stops the filling process automatically. The DC155
works with a decreasing weight signal too.
The scale signal amplifier is used to transform the
weight signal. The small difference signal of the
strain gauge will be amplified, transformed to digital and sent to the Dosing controller.
Correct mounting of the WV157 in hazardous area
is close to the scale to reduce disturbances. The
even more disturbance safe digital output signal
can be transmitted via a longer distance to the
DC155 in hazardous area.

Type code
M a in s :

9 8 # %
2 3 0 V A C ...............................
1 2 0 V A C .................................
2 4 V D C ...................................

Further voltages on demand

.x
.0
.2
.6

Technical Details
Ex- protection

E Ex e m ib IIC T4

EC- type examination c.
Ambient temperature

TÜV 01 ATEX 1694
-20°C ...+50°C T4

Device group
Mounting

II 2 G

Hazardous area, Zone1

Dimensions H x B x T

175 mm x 80 mm x 57 mm

Protection

IP65

Material

Mains: Kl. 11,12
Kl 13

Scale terminal
(intrinsically safe)
Kl. 1 ..6

Aluminium, lacquered

AC: 230 V, 120 V, DC: 24 V
Um = 253 V
PE

U0 = 5,9V, I0 = 153mA,
P0 = 225 mW,
C0 = 1,5 µF I0 = 1,7 mH

Serial interface
(intrinsically safe)
Kl. 7 ..9

U0 = 5,9V, I0 = 13mA,
P0 = 19 mW,
C0 = 575 nF I0 = 40 mH

further limits

see EC- type examination certificate

Kl 10

Sample rate
Precision

Temperature coefficient

PE, shield terminal

0,03%

0,015 %

Block diagram

Connection of 4 weight cells

8 Hz

VE

VE

at 2mV/V

each 10 K