6
TEMPCO s.a. 4e ave. N°114, Z.I. des Hauts Sarts, B-4040 Herstal, Belgique. T:(32)04-2649458, F:(32)04-2649476, www.tempco.be, [email protected]
Les photos et caractéristiques présentés dans ce catalogue sont données à titre indicatif et ne sont pas contractuelles.
3.A.01.450-E-100910 page 3/7
Gage Mounting with Relays Remote
Where it is desirable to mount the amplifier-relay unit sepa-
rate 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.
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.
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, nega-
tive, or differential pressure sensing points. Use 1/4˝ diame-
ter metal or other instrument tubing and 1/8˝ NPT adaptors
at the Dwyer Photohelic
®
pressure switch gage. Adaptors
for rubber or soft plastic tubing are furnished with the instru-
ment for use where this type of connection is preferred.
If the Photohelic
®
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 No. 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.
Fig. 3A
Remote Amplifier-Relay Unit
4-9/32
[108.74]
5
[127.00] SQ
4-9/32
[108.74]
Ø3/16
TYP 4 PLACES
Surface Mounting
Fig. 3B
Hole Layout (Front)
1-1/8
[28.58]
1-1/8
[28.58]
THREE 3/16 DIA.
HOLES AT 120
°
SURFACE MTG.
3/4 DIA. HOLE
FOR WIRE CONN.
Fig. 4A
Hole Layout
Fig. 4B
