Dewetron DEWE-30-16, Technical Reference Manual

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20
2V / Div
0 V
0 V
U
IN
U
OUT+
U
OUT-
Main System
General description
Having wide distance between the DEWE-30-xx and the data acquisition unit (DEWE-5000, DEWE-4010,
DEWE-3020, DEWE-2010 …) causes some problems if high bandwidth and low distortion and noise is re- causes some problems if high bandwidth and low distortion and noise is re-
quired. Similar to all high speed digital signal layer protocols (LAN, IEEE1394, USB, PCI-Express) symmetric
signal transfer using twisted pair cables have to be used to achieve this. The 30-16-DIFF-OUT converts the
standard single ended DEWE-30 output to a balanced differential output with high output current, needed to
drive cables up to 500 m without loosing the high accuracy of the signal amplifier.
Cable configuration
The usage of shielded twisted pair cables is recommended for the connection between DEWE-30-xx and the
data acquisition unit.
Please note that at the data acquisition unit differential input amplifiers are needed.
The shield of the cable have to be connected to the GND pin of the 37-pin female SUB-D connector of
the DEWE-30-xx. In usual system configuration the GND of the DEWE-30-xx and the GND of the data
acquisition unit are tied together via the personal earth of the AC power supply. Therefore the cable shield
should not be connected to the GND of the data acquisition system to avoid GND loops. But if the GND of
both devices are nowhere tied together (at power supply without protected earth) it is also recommended to
connected the shield to the GND of the data acquisition device.
Sensor
Input
Single ended
DAQP-X amplifier
Balanced differential output
of 30-xx-DIFF-OUT amplifier
Switch on DEWE-30-xx rear panel
for connecting amplifier GND
to the housing (personal earth)
R
GND
Differential input amplifier
(e.g. DAQP-V-A)
Data acquisition system
(e.g. DEWE-5000) DEWE-30-xx
Shielded twisted pair cable
Connection depends on
power supply configuration
(see text above)