ABB TTH300 Series, User Manual

Page: 8 / 24

8 TTH300, TTF300 TEMPERATURE TRANSMITTER | SM/TTX300/SIL-EN REV. E
6 Constraints
The following constraints on the use of the compliant item needs to be considered:
- The entire valid range for the output signal must be configured between min. 3.8 mA and max. 20.5 mA (factory setting).
- The HART communication master must comply with the safety requirements of the customer application.
- No HART Multidrop Mode (forces current out to 4mA)
- The low alarm must be configured to a value
á 3.6 mA.
- The high alarm must be configured to a value â 21 mA.
- To ensure reliable functioning of the current output, the terminal voltage at the device must be between
11 to 42 V DC (non-explosion-proof design) and
11 to 30 V DC (explosion-proof design).
- The DCS power supply for the transmitter must be capable to provide the required voltage level even when the current output
is active with the configured high alarm.
- The head mounted electronics TTH300 with IP00 rating according IEC 60529 for the measurement loop must be protected
against environmental influences by an suitable installation housing.
The device does not meet safety requirements under the following conditions:
- During configuration and simulation
- With deactivated write protection
- During an inspection, proof test of the safety function
Before commissioning the device, check whether the device setup assures the system's safety function. Make also sure that the
correct device has been installed at the correct measuring point.
Whenever the device is updated (if the device's mounting position is changed or the setup is modified, for example), the safety
function of the device must be checked again.
Once the safety function has been checked, the device must be write-protected to prevent changes to the setup, since any change to
the measurement system or parameters may impact the safety function.