WARNING
Undetected failure in devices with functional safety
Note the following:
• For the maximum current output signal to be output, set the measuring range within the
maximum permissible measuring span. You can find the maximum permissible measuring
span of your measuring cell in the section AUTOHOTSPOT.
• Note that a saturation limit > 21.5 mA increases the risk of undetected failures.
• When you configure your process control system, the analog input must distinguish
between the measured value at saturation (current is ≤ 21.5 mA) and high fault current
(current is ≥ 22.0 mA).
9.5
Locking the device
9.5.1
Locking the SITRANS TH/TR device
9.5.1.1
Introduction
The following options are available to lock the device:
• Enabling write protection using the jumper.
The table gives you an overview of the write protection options:
Write protection
Read measured values
(measurement view)
Read parameters (param‐
eter view)
Change parameters (edit
view)
Jumper set
Yes
Yes
No
User PIN enabled
Yes
Yes
Yes, after input of the user
PIN
Devices with functional safety
To enable functional safety, first enable the user PIN.
9.5.1.2
Enable SITRANS TH write protection with jumper
Introduction
The jumper is used for enabling write protection.
Parameter assignment
9.5 Locking the device
SITRANS TH100/TH320/TH420/TR320/TR420/TF320/TF420 with 4 to 20 mA/HART
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Operating Instructions, 05/2020, A5E41864807-AB