Alarm signals can be configured to drive analogue output currents outside the working range. The ‹low› alarm changes the output current to 1.00 mA and the ‹high› alarm changes the current to 21.00mA.
There are several module specific types of fault that trigger an alarm response, while the “Transmitter failure” is a common fault, caused typically by micro controller or other system disturbances.
When the output characteristic is selected as “NAMUR” (e.g. for the MTLx532, MTLx573, MTLx575, MTLx576-RTD and MTLx576-THC) then the output current for the ‹high› alarm changes to >22mA.
On the MTLx532, when the output characteristic is selected as “Full scale”, no alarm signal is available.