Specifications

S7-200 Programmable Controller System Manual
426
Table A-27 Configuring the Thermocouple Module DIP Switches
Switches 1,2,3 Thermocouple Type Setting Description
S
W
1
,
2
,
3
J (Default) 000 Switches 1 to 3 select the
t
h
e
r
m
o
c
o
u
p
l
e
t
y
p
e
(
o
r
m
V
S
W
1
,
2
,
3
K 001
thermocouple type (or m
V
operation) for all channels on the
f
Configuration
↑
1
O
n
T 010
p
)
module. For example, for an E
t
y
p
e
,
thermocou
p
le S
W
1=0
,
S
W
2
1234*5678
↑1--
O
n
↓0--Off
E 011
t
y
p
e
,
t
h
e
r
m
o
c
o
u
p
l
e
S
W
1
=
0
,
S
W
2
=1,SW3=1.
*
S
t
D
I
P
i
t
h
4
↓
R 100
* Set DIP switch 4
to the 0 (down) position.
S 101
t
o
t
h
e
0
(
d
o
w
n
)
p
o
s
i
t
i
o
n
.
N 110
+/--80mV 111
Switch 5 Open Wire Detect
Direction
Setting Description
↑
1
O
SW5
Configuration
Upscale
(+3276.7 degrees)
0 0 indicates positive on open wire
1 indi cates negative on open wire
12345678
↑1--On
↓0--Off
C
o
g
u
a
t
o
Downscale
(--3276.8 degrees)
1
Switch 6 Open Wire Detect
Enable
Setting Description
12345678
↑1--On
↓0--Off
SW6
Configuration
Enable 0 Open wire detection is performed
by injecting a 25 µA current onto
the input terminals. The open wire
enable switch enables or disables
the current source. The open wire
range check is always performed,
even when the current source is
d
i
s
a
b
l
e
d
T
h
e
E
M
2
3
1
Disable 1
d
i
sa
b
l
e
d
.
T
h
e
E
M
2
3
1
Thermocouple module detects
open wire if the input signal
exceeds approximately ±200mV.
When an open wire is detected,
the module reading is set to the
value selected by the Open Wire
Detect.
Switch 7 Temperature Scale Setting Description
SW7
Confi
g
uration
Celsius (_C) 0 The EM 231 Thermocouple
module can report temperatures in
Celsius or Fahrenheit. The Celsius
t
F
h
h
i
t
i
i
12345678
↑1--On
↓0--Off
C
o
n
f
i
g
u
r
a
t
i
o
n
Fahrenheit (_F) 1
to Fahrenheit conversion is
performed inside the module.
Switch 8 Cold Junction Setting Description
12345678
↑1--On
↓0--Off
SW8
Configuration
Cold junction
compensation enabled
0 Cold junction compensation must
be enabled when you are using
thermocouples. If cold junction
compensation is not enabled, the
conversions from the module will
b
e
i
n
e
r
r
o
r
b
e
c
a
u
s
e
o
f
t
h
e
v
o
l
t
a
g
e
Cold junction
compensation disabled
1
b
e
i
n error
b
ecause o
f
t
h
evo
l
t
age
that is created when the
thermocouple wire is connected to
the module connector . Cold
junction is automatically disabled
when you select the ±80mV range.