RKI Instruments SDM-E2 - Manual (Page 24)

19 • Hardware Setup
Connecting Calibration Gas
The GAS 1 and GAS 2 fittings on the back of the docking station are designed to be
used with a calibration gas cylinder that is fitted with a demand flow regulator. The
AIR fitting may be used with a demand flow regulator and a cylinder of zero
emissions air, but this is not normally necessary since the docking station will
generally be in a fresh air area.
GAS 1
The type of calibration gas cylinder used for the GAS 1 fitting depends on the gas
sensors installed in the EAGLE 2. A 4-gas mix, LEL/Oxygen/CO/H2S, is used for the
GAS 1 fitting if the instrument being used with the docking station is a standard 4-gas
unit or is a version that has less than four standard channels but still has an H
2
S
channel. If the instrument does not have an H
2
S channel, then a 3-gas mix, LEL/
Oxygen/CO, is used for the GAS 1 fitting. Although a 4-gas cylinder will work for an
instrument of any standard gas combination, if you have multiple 3- and 4-gas
instruments, you may want to keep a 4-gas cylinder and a 3-gas cylinder to help
preserve the charcoal filter that protects the CO sensor in instruments without an H
2
S
channel.
GAS 2 for EAGLE 2s with One Special Sensor
The GAS 2 fitting is intended to be used for special sensors (i.e. PID, TC, ESM-01,
etc.) when GAS 1 is used for standard sensors. If you have a special sensor installed
(i.e. PID, TC, ESM-01, etc.), a special cylinder for the target gas of that sensor needs
to be used for calibration. For example, if you have a standard 4-gas unit plus a PID
sensor, you will need both a 4-gas cylinder and a cylinder of 10 ppm isobutylene for
low range or 100 ppm isobutylene for high range calibration. The isobutylene cylinder
needs to be connected to the GAS 2 fitting on the back of the SDM-E2. Similarly, if
you have a standard 4-gas EAGLE 2 plus an ammonia ESM-01 sensor, you will need
a cylinder of 10 ppm ammonia connected to the GAS 2 fitting on the back of the
SDM-E2. If you have an EAGLE 2 configuration for which a 5-gas cylinder is available
(ie. standard 4-gas plus SO
2
or standard 4-gas plus high range PID, you may use the
5-gas cylinder and connect it to the GAS 1 fitting. You will have to assign the SO
2
or
high range PID channel to GAS 1 instead of GAS 2 during bump testing or
calibration. See “Bump Testing an Instrument with Special Sensors” on page 71 or
“Calibrating an Instrument with Special Sensors” on page 87 for further instruction.
Some infrared sensors can be bump tested or calibrated at the same time as the
standard gases using a 3- or 4-gas cylinder. In these cases, a second cylinder is not
needed for the GAS 2 fitting. See “Appendix B: Bump Testing and Calibrating EAGLE
2s with IR Sensors” on page 218 for a description of infrared sensor gas port
assignments.
GAS 2 for EAGLE 2s with Two Special Sensors
If you have an EAGLE 2 with two special sensors installed, for example, a standard 4-
gas EAGLE 2 plus a PID sensor and an ammonia ESM-01 sensor, you will need both
an isobutylene calibration cylinder and an ammonia calibration cylinder. For
instruments with 2 special sensors, the calibration cylinder for the first special sensor
channel (typically channel 5) needs to be connected to the GAS 2 fitting first. During
bump testing or calibration, the PC Controller program will prompt you to change the
GAS 2 calibration cylinder when it needs to calibrate the second special sensor