Siemens S5-135U/155U appendix 24V

Analog Input/Output Modules

9.3.11Connecting Resistance Thermometers in the Extended Pt 100 Range

The series-connected resistance thermometers (up to 8 Pt 100s) are fed with a current of 2.5 mA (IC+/IC-) by a constant current generator. The voltage at the Pt 100s is picked off at measurement inputs M+ and M-.

In this mode, the temperature range of approximately -100 °C to +100 °C has a more accurate resolution. The mode is printed on the cover of the module as follows: ªresistance thermometer compensated low range.ºYou should only use the 6ES5 498-1AA11 range card (" 50 mV / 500 mV).

Unused inputs must be connected in parallel to a wired input. In the following figure, for example, these are the inputs CH4 to CH7.

	M+
	Ch0	6ES5498-
	M±	1AA11
	M+
	Ch1
	M±
	M+
	Ch2
	M±
	M+
	Ch3
	M±
	M+	6ES5498-
	Ch4
		1AA11
	M±
	M+
	Ch5
	M±
	M+
	Ch6
	M±
	M+
	Ch7
	M±
	Ic±
	Ic+
24V	L+	2.5mA
M24V	L±

Figure 9-10 Connecting Resistance Thermometers in the Extended Pt 100 Range

System Manual	9-21
C79000-G8576-C199-06