MP Filtri ICM, Руководство пользователя

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60 Analog 4-20mA Modes
20 Analog 4-20mA Modes
The ICM provides two analog 4-20mA current loop outputs, A and B. In order to
provide the possibility of transmitting more than two parameters, several different
modes can be chosen to suit the application.
20.1 Fixed - NAS1638 and RH
The ICM result format must be set to NAS1638. The outputs then simply indicate
the NAS1638 contamination class and the RH level as follows:
Output A Contamination 4mA NAS 00
Code 5mA NAS 0
= 𝑚𝐴 − 5
6mA NAS 1
…
17mA NAS 12
20mA OVERRANGE
Output B RH % 4mA 0% RH
= (𝑚𝐴 − 4) ∗ 100/16
5mA 6.25% RH
20mA 100% RH
20.2 Time Multiplexed Schemes
These output the result parameters on a single output (A) in a timed sequence. This
mode would be used to read the result parameters in to a PLC. The PLC would need
to be programmed to read each parameter at the correct time.
These modes are still under development, please contact MP Filtri UK for details.
•
We output a current <5mA (4.0mA) for 1 second to indicate start of "frame".
The PLC needs to continuously check for this condition so that it can start the
timer sequence for acquiring the results.
•
Parameters are output in a sequence, one parameter per second until the end of
the list.