Page 10 - Wagp_InterfaceElectronic_Volume4_2015_US.pdf

0 WAGO Signal Conditioners and Relay Modules

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JUMPLFEX , 857 Series
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At the input side the devices required Parameterization, commissioning
active signals, i.e., the sensor signal is and diagnostics using WAGO-frame
generated by a dedicated supply volt- A portion of the JUMPFLEX transducer
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age. can be configured for parameterization,
These devices provide a filtered and commissioning and diagnostics of field
amplified signal at the output side. devices using WAGOframe, a software
based on the FDT/DTM standard.
Passive isolation
The WAGOframe FDT frame applica-
A passive isolator draws power for signal tion provides a wizard, which simplifies
transmission from the input circuit. In this the operation of components, such as
case, the sensor must supply a power ®
The perfect match of housing and elec- WAGO JUMPFLEX DTMs. This wizard
tronics is the key to a highly successful level adequate for the device and must guides the user through the different
device. This is exactly what has been also drive the working resistance. operating modes of DTM device drivers.
achieved by WAGO with the transducers As a result, it must be ensured that the
and relay modules of the 857 Series. current-driving power of the sensor is suf-
ficient to drive the maximum current of
Analog systems technology — Basics 20mA via the passive isolator (with the
device-specific voltage drop), as well as
Problems can arise in signal processing
in industrial systems of analog standard the working resistance.
signals (such as 0-10V or 0-20mA) which
can have an adverse effect on overall
fault-free signal processing. Problems This can be calculated using the follow-
such as potential differentials arising ing equation:
from interlinked measuring circuits can
be efficiently prevented using WAGO
transducers, with their associated electri- US ≥ UE = UV + 20 mA x RB
cal isolation.
Decoupling (Isolation) methods US 3 different connecting techniques are
employed for acquisition of resis-
A basic distinction is made between I UE ____> I I RB tance thermometers:
active and passive isolation.

2-wire connecting technique
__________________>
UV = 2.0 V
1
Active isolation Typical equation for a passive isolator 2
(857-451) for a 20mA signal. 3
Depending on the design and model in 4
use, devices are available that incorpo-
rate electrical 3-way isolation. 4-way iso- US ≥ UE = 2.0 V + 20 mA x 600 Ω 2-wire
lation is provided in a signal duplicator.
This means that all inputs, outputs and US ≥ UE = 14 V The resistance thermometer is connected
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supply circuits are electrically isolated to the JUMPFLEX transducer via a two-
from one another with a 2.5 kV proof wire conductor. As the feed-in resistance
voltage. can directly affect results, which would
Temperature measuring techniques invalidate them, it must be ensured that
the distance between the measuring point
Resistance thermometers, such as Pt100 and the device is kept as small as pos-
sensors, alter their resistance level as a sible. This distance should not exceed
function of temperature. For example, 10m in this case. If this distance can
a rise in temperature will result in an not be ensured, the 857-801 unit can
increase in the resistance level. This be used provide compensation for the
reistance level is registered by the JUMP- incoming resistance using the configura-
FLEX devices (for example 857-800) and tion software.
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2.5 KV transformed into an analog output signal
Safe Isolation
and simultaneously electrically isolated
This ensures that the greatest possible using a 2.5kV proof voltage.
safety and reliability is achieved for the The analog standard signal can be a
system and any devices connected to the current signal in the 0-20 mA, 4-20 mA
system. For 3-way isolation provides for 0-10 mA or 2-10 mA range, or a voltage
electrical isolation between the transduc- signal in the 0-10 V, 2-10 V, 0-5 V or
ers and the control system and between 1-5 V range.
the control system and the control ele-
ments.