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Analog input/output modules – Siemens S5-135U/155U User Manual

Page 402

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9-20

System Manual

C79000-G8576-C199-06

9.3.10

Connecting Resistance Thermometers in the Standard Pt 100

Range

The series-connected resistance thermometers (up to 8 Pt 100s) are fed with a
current of 2.5 mA (I

C+

/I

C-

) by a constant current generator. The voltage at the

Pt 100’s is picked off at measurement inputs M+ and M-. In this mode, the
whole temperature range of the Pt 100 (-200

°

C to +840

°

C) is available. The

mode is printed on the cover of the module as follows:
“resistance thermometer uncompensated full range.” Other voltage sensors
can be connected in a floating circuit at the M+/M- inputs of a card which are
not assigned to resistance thermometers (voltage range 500 mV).

Pt 100

+

MUX

Card 1

460 Analog Input Module

#

D

A

CH0

CH2

CH1

CH3

M–

M +

Card 2

CH4

0...500 mV

U

CM

2)

1)

CH7

I

C–

L –

L +

0 V Bus

2.5 mA

const.

Pt 100

Pt 100

Pt 100

I

C+

U

CM

0...500 mV

Range
Card for
4 Inputs
6ES5 498-
-1AA11

Range
Card for
4 Inputs
6ES5 498-
-1AA11

Figure 9-9

Connecting Resistance Thermometers in the Standard Pt 100 Range

1)

If no Pt 100 is connected to CH4 to CH7, other voltages and currents can be measured at these channels with cards

6ES5 498-1AA21, 6ES5 498-1AA31, 6ES5 498-1AA41, 6ES5 498-1AA51, 6ES5 498-1AA61, 6ES5 498-1AA71.

2)

When cards 6ES5 498-1AA41, 6ES5 498-1AA51 or 6ES5 498-1AA71 are used, a short-circuit jumper is not required.

Analog Input/Output Modules