Yokogawa AC8 Calibration Units - Manual (Page 3)

3
IM 11M6D2-02E-A
I. INTRODUCTION
This manual details the operating instruction for the Yokoga-
wa Model AC4/AC8 Automatic Calibration Unit, and the
integration with the AV550G Zirconia Oxygen Averaging
Converter.
IMPORTANT
The maximum input pressure for the span and zero gases is 35
psig. Exceeding 35 psig may result in damage to the AC4/AC8.
II. OVERVIEW
The AC4/AC8 Automatic Calibration System is designed to
work with the AV550G Oxygen Averaging Converter, provid-
ing accurate, automatic or semi-automatic calibration of the
ZR22 Zirconia Oxide Detector. The AC4/AC8 is assembled
with plumbing, flow control hardware and internal solenoid
wiring necessary to calibrate up to four or eight probes
respectively. The end user need only provide plumbing to the
individual probes, calibration gases, and interconnection wir-
ing between the calibration unit and the converter.
Initial setup of the auto cal unit is further simplified by the
use of manual overrides for all solenoids. The overrides,
coupled with the flow regulation for each probe, allow for
fast balancing of each calibration line. Each probe also has
its own flow meter and flow control for the reference air flow.
2.1 Models AC4/AC8 Multi-Channel Automatic
Calibration
UStandard Specifications
Operating Pressure: 20 psi
Maximum Pressure: 35 psi
Flow meter range:
0.15 to 1 LPM (separate flow meter
for cal gas and reference air)
Flow rate: Cal Gas – 0.6 LPM;
Reference Air – 0.8 LPM
Cal tubing: 1/4” copper (standard);
1/4: stainless steel (optional)
Gas connection: 1/4” FNPT
Voltage: 110 VAC, 50/60 Hz (standard)
Ambient temp.: 80°C (176°F) maximum
Weight: Approximately 40 lbs (18 kg)
Construction: Outdoor installation (Indirect sunlight)
Enclosure: NEMA 4 or NEMA 4X
Reference gas
Consumption:
0.8 LPM per probe
Cal Gas Consumption
(Zero & Span):
0.6 LPM per probe,
during calibration only
NOTE
Instrument air is used for both span calibration gas and
reference air.
Model and code
AUTO CALIBRATION UNIT FOR AV 550G
AC4 4 Channel System
AC8 8 Channel System
ENC LOS URE
-4 NEMA 4
-5 NEMA 4X
PLUM BING
-C Copper tub ing , brass fittings
-S Stainless steel tubing and f ittings
REFE RENC E AIR FLOW MET ER
-R*U Reference air flow meter
OPTIONS
/SC T Stainless Steel Tag
III. INSTALLATION
3.1 LOCATION
The following guidelines should be used when selecting a
location for the auto-calibration unit.
1. The unit must be easily accessible for maintenance and
inspections.
2. The unit must be near the ZR22 probes as practical. This
will minimize the length and amount of tubing required for
plumbing.
3. Ambient temperature will not exceed 80°C (176°F).
4. Humidity is moderate and no corrosive gases are present.
5. Minimal presence of vibration.
6. Availability of 120 VAC and clean, dry instrument air.
7. Adequate spacing for reference and zero gas plumbing.
8. Not positioned in direct sunlight.
NOTE
If ambient atmosphere contains corrosive gases or high dust,
the use of air purging is recommended.
3.2 MOUNTING
The unit is designed for wall mounting by securing the four
standoffs with bolts. Allow for sufficient space to connect the
copper or stainless steel lines to both sides of the enclosure.
Input gases (zero calibration gas and instrument air) are
connected to the left side, while all probe connections (cal
lines and reference air) are on the right side, when facing the
unit. Refer to Figure 1 for mounting dimensions and required
clearances.
IMPORTANT
Care must be taken to mount the unit as level as possible to
ensure the accuracy of the flow rates. If the unit is not level, the
flow rates will not be accurate!