Operation
42 Rev. D7 Jul 2017 Marathon MM
7.4 Inputs and Outputs
7.4.1 Milliamp Output
The milliamp output is an analog output you can connect directly to a recording device (e.g., chart
recorder), PLC, or controller. The mA output can be forced to a specific value through the DataTemp
Multidrop software or a programming command according to section 10.9.1 Current Output, page 75.
This feature is useful for testing or calibrating connected equipment.
Figure 22: Wiring the Terminal
7.4.2 Relay Output
The relay output is used as an alarm for failsafe conditions, see section 11.2 Fail-Safe Operation, page 82,
or as a threshold relay. Relay output relates to the currently displayed temperature on the control panel
display. The relay output can be used to indicate an alarm state or to control external actions. The relay
contacts can be set either to N.C. (normally closed: relay contacts are closed while in the home position)
or N.O. (normally open: relay contacts are open while in the home position). The relay can also be forced
on or off for testing connected equipment through the DataTemp Multidrop software or a programming
command, see section 10.9.2 Relay Output, page 75.
7.4.2.1 Thresholds
The relay output has two user selectable thresholds. The two thresholds are set by default to the bottom
temperature range. Activating and adjusting the threshold value is accomplished through the
DataTemp Multidrop Software. Once one or both thresholds are activated the relay changes state as the
current measured temperature passes the threshold temperature.
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