ETAS
Hardware Description
ES420.1 - User’s Guide
20
4.2
Block Diagram
Fig. 4
-
2
Block Diagram
The ES420.1 is a module with eight identical sensor channels with common
Cold Junction Compensation, two shared Ethernet interfaces and a power sup
-
ply.
4.3
Sensor Channels
All sensor channels of the ES420.1 are identical. The thermocouple cold junc
-
tion channels have a resolution of 24 bits. You can use thermocouple cold junc
-
tions of types B, E, J, K, N, R, S and T. The maximum measurement range,
distributed over all thermocouple cold junction types, is
-
210 °C to +1820 °C.
To operate different thermocouple cold junctions on the ES420.1, you can
order special splitter cables from ETAS for the relevant thermocouple cold
junction types (see the section 9.2.1 on page 93).
The special splitter cables for the individual thermocouple cold junction types
are made of the same material combination as the thermocouple cold junc
-
tions. To ensure a high level of accuracy over the entire temperature range,
thermo lines of the relevant type are used with the splitter cables (e.g. NiCr and
Ni with the splitter cable CBATK).
The material transition from the thermo line to the gold-plated contacts of the
master plug is the cold point. The cold point is measured together for all chan
-
nels with a PT100 embedded in a solid copper core. The copper core ensures a
very even distribution of the cold point temperature of all channels. The cold
point is protected against fast or erratic temperature changes of the environ
-
ment with a thermally highly isolating design. The design of the master plug
guarantees that the measure result is only influenced by a few tenths of a Kel
-
vin even with fast temperature changes or uneven temperature distribution
(e.g. if installed near the exhaust system or air vents).
The thermocouple channels are galvanically isolated from one another, from
the supply voltage and from the device ground. This makes it possible to use
non-isolated thermocouple cold junctions in non-potential-free systems with
-
out any negative effect on the accuracy.
FPGA
Open TC
Det ection
Channel 8
Channel ...
Channel 1
ES420
Et hernet
Phy
Et hernet
Traff ic
Detect ion
100
M Bit /s
Et hernet
Connect or
(Host
direction)
Synchronous Sampling
...
M
eas
u
rem
ent
C
on
tr
ol
le
r
24-Bit A/D
Converter
24-Bit A/D
Converter
Splitt er
Cable
Connect or
Splitt er cable
CBATx4xx
TEDS
Open TC
Detect ion
D
iagn
o
st
ic
Un
it
TEDS
Interf ace
Ti
m
e
Sy
nc
hr
on
iz
at
io
n
Un
it
Ethernet
Phy
100
M Bit /s
Ethernet
Connector
On
Automatic
On-board
t emperature
P
ro
toc
ol
E
ngi
n
e
Frame
Generator
Cold Junct ion
Volt age
Regulat or
5...50V