Hach-Lange SI794 D tr User Manual - Manual (Page 26)

Safety functions
Hold mode
Display:
The Hold mode is a safety state during configuration and calibra-
tion. Output current is frozen (Last) or set to a fixed value (Fix).
Alarm and limit contacts are disabled.
If the calibration or configuration mode is exited, the transmitter
remains in the Hold mode for safety reasons. This prevents un-
desirable reactions of the connected peripherals due to incorrect
configuration or calibration. The measured value and “HOLD” are
displayed alternately. The transmitter only returns to measuring
mode after enter is pressed and 20 seconds have passed.
Configuration mode is also exited automatically 20 minutes
(timeout) after the last keystroke. The transmitter returns to
measuring mode.
Timeout is not active during calibration.
Response of output signal:
Last:
The output current is frozen at its last value.
Recommended for short configuration procedures.
The process should not change decisively during con-
figuration. Changes are not noticed with this setting!
Fix: The output current is set to a value that is noticeably
different from the process value in order to signal the
control system that the transmitter is being worked at.
26