Dwyer Instruments 3000 Serie Manual De Instrucciones Y Operación página 3

Gage Mounting with Relays Remote
Where it is desirable to mount the amplifier-relay unit separate from the
gage-phototransistor unit, the gage may be mounted either as shown in
Fig. 2 (except less amplifier-relay portion) or surface mounted as shown
in Fig. 3A. Use the layout shown in Fig. 3B to locate holes. The complete
package cannot be surface mounted.
Surface Mounting
Hole Layout (Front)
Remote Relays Mounting
The amplifier - relay unit may be mounted remotely as shown in Fig. 4A.
Use the hole layout as shown in Fig. 4B for this option.
Additional mounting information for special requirements is available
from the factory.
Fig. 3A
THREE 3/16 DIA.
HOLES AT 120°
SURFACE MTG.
3/4 DIA. HOLE
FOR WIRE CONN.
1-1/8
[28.58]
1-1/8
[28.58]
Fig. 3B
Remote Amplifier-Relay Unit
Hole Layout
4-9/32
[108.74]
5
[127.00] SQ
4. Pneumatic Connections & Zeroing
After installation but before making pressure connections, set the
indicating pointer exactly on the zero mark, using the zero adjust screw
located at the bottom of the front cover. Note that this adjustment can
only be made with the high and low pressure taps both open to
atmosphere.
Connect the high and low pressure taps to positive, negative, or
differential pressure sensing points. Use 1/4˝ diameter metal or other
instrument tubing and 1/8˝ NPT adaptors at the Dwyer
pressure/switch gage. Adaptors for rubber or soft plastic tubing are
furnished with the instrument for use where this type of connection is
preferred.
If the Photohelic ® Switch/Gage is not used to sense differential pressure,
one of the pressure taps must be left open to atmosphere. This will allow
the reference pressure to enter. In this case, installation of a Dwyer
A-331 Filter Plug or similar fitting in the reference pressure tap is
recommended to reduce the possibility of dust entering the instrument.
Note: If the Photohelic ® switch/gage is over pressured, pointer may
'jump" from full scale back to zero and remain there until the excess
pressure condition is relieved. Users should be aware of possible false
zero pressure indications under this conditions.
Bulletin B-33
Fig. 4A
Ø3/16
TYP 4 PLACES
4-9/32
[108.74]
Fig. 4B
® . Photohelic
page 3
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