Viatran MODEL 34B Pressure Transmitter

PRODUCT OVERVIEW All information contained in this document is representative of a standard Model 34B. If the product you ordered
has special requirements or modifications, refer to the information marked on the product and your purchase
order for possible alteration to the product’s configuration. Failure to verify product configuration before installation may cause permanent product damage and in most cases, void the manufacturer’s product warranty. If you
are unsure or have questions about your product, please contact our Application Engineers for assistance.
Remove and retain all instruction manuals and performance certificates that are shipped with the product. These
documents provide important information on the product’s calibration, operation, safety precautions,
recommended maintenance, recalibration requirements, repair service instructions and warranty information.
These documents are updated from time to time as changes to the product occur and should be reviewed at
receipt so that proper and safe installation can occur.
GENERAL REQUIREMENTS & CAUTIONS
1. All electrical & pressure connections should be compatible with the model specifications as outlined below.
2. Installation should occur only after electrical (input power) and line pressure is verified as being off and at
zero.
3. The 34B is susceptible to sensor damage by being dropped, struck, or installed in a high vibration
environment.
4. The product’s internal electrical circuitry is isolated from case ground. The case or ground of the unit should
not be connected to the input, output or calibrate pins of the product or wiring system. Ground loops and line
noise will affect the product’s performance and will in most cases cause internal electrical failure. The
transducer housing should never have power applied to it.
5. All products should be protected from direct or continued exposure to fluids at the electrical connection. It is
recommended that for products installed in areas where the potential for contamination at the electrical
connection is possible a “boot” or other protective measure be taken to eliminate possible deterioration of the
product’s electrical connection and corrosion that will impede product performance.
6. On some lower range models a breather opening, with breather plug, is used to allow for proper product
function. At no time should any mist, vapor or fluid be permitted to enter this breather as unit failure may
occur. (A protective cover may be required.)
7. At no time should an object be inserted into the pressure port or pressed against the sensing area to deflect
the sensor (to test or simulate pressure), as on some models permanent damage to the sensing diaphragm
may occur.
8. Never exert excessive inward force on the adjustment screw, as the potentiometer could break away from the
electronics and cause immediate or partial electronic failure.
9. When shipped in quantities, units should be packaged individually to eliminate possible damage.
10. The model 34B is CE compliant. The CE circuitry requires the transducer housing to be grounded.
Power should never be applied to the housing.
BASIC OPERATION The Model 34B has an optional external adjustment which allows the user to fine-tune the zero reading by use of
a potentiometer. Please note the nylon cover screw must be removed to gain access to the potentiometer. The
adjustment screw is a 10-turn potentiometer and only requires a slight turn to adjust. The potentiometers will
provide a nominal zero adjustment of approximately ±10% of the Full Scale Output.
OPTIONAL ‘DA’ (ISOLATED SHUNT) or ‘LV’ (EXT. POWERED) CALIBRATION CIRCUIT
An internal calibration circuit is optional on the Model 34B. This feature provides the user a confirmation that the
unit is still in calibration. This is especially useful when a standardized pressure source is not available. The
operation has the user either short or apply 8-26V to the two conductors, which will electronically simulate an 80%
pressure being applied to the instrument. The exact pressure and equivalent signal output for each individual
instrument is listed on the product’s calibration certificate as are the wires, or pins, used for this feature. This
feature is also useful when the transducer’s signal will be sent to a readout device, such as a digital meter, and
the user requires some known calibration points. Shorting the conductors will provide a known calibration value
to the meter allowing for quick setup of the system.
In all cases, the calibration signal is referenced from atmospheric pressure, or zero PSIG, with the exception of
2 98MANAL34B Rev. G