Endress+Hauser Cerabar S PMC71, Functional Safety Manual

Page: 35 / 48

Cerabar S PMP71 Appendix
Hauser 35
8 Appendix
8.1 Structure of the measuring system
8.1.1 System components
1 4 5 7
9
6 8 2 3
A0028746
1 PLC (programmable logic controller)
2 2 transmitter power supply units, e.g. RN221N (with communication resistor)
3 Connection for Commubox FXA191, FXA195 and Field Communicator
4 HART handheld terminal, e.g. Field Communicator
5 Computer with operating tool
6 Commubox FXA191 (RS232) or FXA195 (USB), FXA291
7 Field Xpert
8 VIATOR Bluetooth modem with connecting cable
9 Transmitter
An analog signal (4 to 20 mA) that is in proportion to the pressure is generated in the
transmitter. This is sent to a downstream logic unit (e.g. PLC, limit signal transmitter, etc.)
where it is monitored to determine whether it is below or above a specified limit value.
For fault monitoring, the logic unit must be able to detect both HI alarms (≥ 21.0 mA) and
LO alarms (≤ 3.6 mA).
8.1.2 Description of use as a protective system
The pressure transmitter is used for the following measuring tasks:
• Absolute pressure and overpressure measurement in gases, vapors or liquids in all areas
of process engineering and process measurement technology
• Level, volume or mass measurements in liquids
8.1.3 Installation conditions
The installation conditions for various measurements are described in the Technical
Information for the device.
Correct installation is a prerequisite for safe operation of the device.
8.1.4 Measurement function
The measuring principle and the measurement functions are described in the Technical
Information for the device