Yokogawa 415 Steam and Gas - Manual (Page 51)

4.4 THE RELAY OUTPUT OPTION
The Relay output option consists of two Form C relays which can be preset
during calibration to energise when the Default flowrate exceeds or drops below
the preset values.
The "low" relay is energised whenever the rate is below the preset value, and the
"high" relay is energised whenever the rate exceeds the preset value. The preset
values are programmed during calibration as described in section 5.
Options 49
34
35
36
31
32
33
Relay 2
High Alarm
Relay 1
Low Alarm
Normally Open
Normally Closed
Common
Normally Open
Normally Closed
Common