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Analog Value Processing
Wirebreak Signal in Conjunction with Resistance Thermometers
An interruption in the supply leads to a resistance thermometer is reported as follows:
Table 10-34. Wirebreak Signal in Conjunction with Resistance Thermometers
Digitized Analog Value
Wirebreak on
(460/465 Module)
M+
M -
PT 100 (resist.-
type sensor)
S+
S -
*
On the 460 analog input module, the value "0" is also decoded for the unbroken PT 100 resistors and error bit
F set to 0.
The overflow bit is set separately for each channel in the case of the 460/465-7LA12 modules.
The S+lines to the resistance thermometer can be monitored for a wirebreak on the 465 -7LA12
analog input module by setting switch 7 of mode selector I to "PT 100" (PT 100 constant power
supply). The error bit is also set to flag a wirebreak in this line.
Unused channels can be used to measure voltages or currents when the current sourcing outputs
(S+, S -) associated with the relevant measuring channel are short-circuited with a jumper.
Without this jumper, the error bit would be set for this channel and the value "0" decoded.
The S+lines are not monitored for wirebreak when mode selector II is in the "Current or voltage
measurement" position. In this case, the error bit is not set when a wirebreak occurs. This switch
setting should be selected when only voltages or currents are to be measured (see Figure 10-7).
The following general rule applies: When the wirebreak signal is to be issued, the measuring
circuit must have a low resistance (<1 k
10-52
Status of the Error Bit
(460 Module)
0/0
0/0
0
*
/0
0/0
0/0
).
Status of the Error
Bit (465 Module)
1
1
1
1
0
*
1
0
1
0
1
EWA 4NEB 811 6130-02b
S5-115U Manual
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