Scaling The Range Of Values; Diagnostics; General - Festo CPX-4AE-4AA-H Description/Commissioning

Diagnostics

9.6

Scaling the range of values

For the scalable data format, the range of values can be scaled by setting the critical limits. To process
the diagnostics correctly, the distance between both critical limits should amount to at least 100
1. Set the "linear scaling" data format
è Tab. 18 Description of the "Data format, monitoring according to NAMUR NE43" module
parameter.
2. Set the critical limits for each channel
è Tab. 20 Description of "Lower critical limit of channel 0 ... 3",
è Tab. 21 Description of "Upper critical limit of channel 0 ... 3".
The critical limits represent the scaling end values:
– When the upper critical limit is positive, set the upper critical limit before setting the lower
critical limit.
– If the upper critical limit is negative, set the lower critical limit before setting the upper critical
limit.
Example: scaling appropriate for a pressure sensor
The sensor linearly converts the measuring range 0 ... 6 bar to analogue current values 0 ... 20 mA um.
Actual value (examples)
0 mA
10 mA
20 mA
22 mA
Tab. 43 Example of scaling and limit monitoring for a pressure sensor
10 Diagnostics
10.1

General

Specific errors of the analogue module are reported or suppressed dependent on the module para-
meterisation
è Tab. 16 Description of the "Module CPX monitoring, parameterisation of error control" module
parameter.
The monitoring of the errors can be activated or deactivated independently of each other. Active mon-
itoring has the following effect:
è The error is sent to the CPX bus node.
è The module error LED and channel error LED light up.
The representation of errors in the bus nodes depends on the bus protocol è Description of bus
nodes.
A further possibility for diagnostics is the operator unit CPX-MMI. The operator unit displays the error
messages in clear text è Description of operator unit CPX-MMI.
50
Digital input value
0
3000
6000
6600
Meaning
Lower critical limit
Value in nominal range
Upper critical limit
Critical limit exceeded
Festo — CPX-4AE-4AA-H — 2019-04a
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