Siemens S5-135U/155U appendix Current Measuring Ranges from 4 to, 20 mA, Current Limiting

Analog Input/Output Modules

Measured-Value	Measuring range 500 mV; card with 31.25 ohm shunt
Representation for	(6ES5 498-1AA51/AA71)
Current Measuring
Ranges from 4 to	The 4 to 20 mA range is resolved to 2048 units at an interval of 512 to 2560.
20 mA	If you require a representation from 0 to 2048, you must subtract 512 units by
	software. Please note the following:
	S A broken wire signal cannot be emitted.
	S Detection of the overrange can be achieved by scanning bits 29 and 211.
	S A broken wire can be detected with currents < 3 mA.

Current Limiting

SIf you short-circuit the positive and negative terminals of the transducer when using the 6ES5 498-1AA51 range card (for a two-wire transducer), the current is limited to about 28 mA. Until the thermal current limiting circuit responds in the range card (about 3 s), a short-circuit current of approximately 250 mA flows; this sets the overflow bit for this duration at all channels.

Units

w4096

4095

3072

3071

2561

2560

2048

512

511

384

383

0

Input Cur- rent in mA

w32.000

31.992

24.0

23.992

20.008

20.0

16.0

4.0

3.992

3.0

2.992

0

		Byte 0								Byte 1
7	6	5	4	3	2	1	0		6	5	4	3	2	1	0
								7
S	211 210 29 28 27 26 25							24 23 22 21 20 A						E	OV
0	1	1	1	1	1	1	1	1	1	1	1	1	0/1	0	1	Overflow
0	1	1	1	1	1	1	1	1	1	1	1	1	0/1	0	0	Overrange
0	1	1	0	0	0	0	0	0	0	0	0	0	0/1	0	0	Short-circuit with two-
0	1	0	1	1	1	1	1	1	1	1	1	1	0/1	0	0	wire transducer
0	1	0	1	0	0	0	0	0	0	0	0	1	0/1	0	0
0	1	0	1	0	0	0	0	0	0	0	0	0	0/1	0	0
0	1	0	0	0	0	0	0	0	0	0	0	0	0/1	0	0	Rated range
0	0	0	1	0	0	0	0	0	0	0	0	0	0/1	0	0
0	0	0	0	1	1	1	1	1	1	1	1	1	0/1	0	0	Range
0	0	0	0	1	1	0	0	0	0	0	0	0	0/1	0	0	underflow
0	0	0	0	1	0	1	1	1	1	1	1	1	0/1	0	0
0	0	0	0	0	0	0	0	0	0	0	0	0	0/1	0	0	Broken wire

A = Active bit

E = Error bit

OV = Overflow bit

S = Sign

9-28	System Manual
	C79000-G8576-C199-06