| 摘要 |
FIELD: physics. ^ SUBSTANCE: field instrument is connected to a control unit via a data bus, the control unit requests personal identifier of the field instrument periodically, and compares it to the stored identifier, and if the identifier differs an alarm or warning message is issued, and the requested identifier is saved to the databank with a timing mark. ^ EFFECT: eliminates unauthorised manipulation of field instruments. ^ 11 cl, 1 dwg |
