Here's a helpful response from Elk about connecting an output to an input.
"It is possible to have one of the M1s Low Voltage Outputs connected to a Zone Input but not to the NEG of the zone. Please make sure to assign a Wiring Type of 0 = End of Line Supervised/ RF and you will need to connect the 2.2KΩ Resistor across the ZN and NEG --- in this scenario you will have two wires under the ZN terminal (one from the low voltage output and the other is the resistor). Create your rule to turn on the Output which will cause the zone to go HIGH and appear as Open or Violated."
"It is possible to have one of the M1s Low Voltage Outputs connected to a Zone Input but not to the NEG of the zone. Please make sure to assign a Wiring Type of 0 = End of Line Supervised/ RF and you will need to connect the 2.2KΩ Resistor across the ZN and NEG --- in this scenario you will have two wires under the ZN terminal (one from the low voltage output and the other is the resistor). Create your rule to turn on the Output which will cause the zone to go HIGH and appear as Open or Violated."