Siemens S5-135U/155U appendix Broken Wire Signal, Standard Pt Range, Extended Pt

Analog Input/Output Modules

9.3.12Broken Wire Signal

Broken Wire	An open-circuit in the lines to a resistance thermometer is indicated as
Signal in the	follows:
Standard Pt 100
Range

Broken Wire at

Module Reaction, Encoded Value

Error Bit E

M+

M±

Pt 100

IC+

IC±

0

0

01)

0

0

1

1

1

0

0

	1) With the 460 analog input module, the value 0 is also encoded for the intact Pt 100 resistances
	because the auxiliary circuit is interrupted; the error bit will not be set for these channels.
	If the mode ªwithout broken wire signalº is selected on the module, an
	open-circuit of the resistance thermometer is indicated with an overflow.
	Unassigned channels can be used for voltage or current measurement.
Broken Wire	If a line of the auxiliary circuit (IC+, IC-) is interrupted, the ªnegative range
Signal in the	limitº is encoded for all inputs and the overflow bit is set to ª1.º In the event
Extended Pt 100	of a sensor or measuring line open-circuit, the error bit is additionally set to
Range	ª1º for the relevant channel.

9-22	System Manual
	C79000-G8576-C199-06