Honeywell Sensepoint XRL Instruction Manual page 32

Maintenance
32
A calibration cap accessory is available for the application of reference
gas for the purpose of calibration. To fit the calibration cap, follow the
steps below.
1. Push the calibration cap on the
sensor cover as shown.
2. Connect a tube from a cylinder of
calibration gas to either of the
calibration cap's gassing ports.
3. Connect another tube to the other
gassing port, and place the end of
this tube in a position so that gas can
exhaust safely away from the work
area and other personnel.