Setra System Model 205-2 - Manual

OPERATING INSTRUCTIONS
MODEL 205-2 PRESSURE TRANSDUCER
FOUR-WIRE, VOLTAGE OUTPUT
GENERAL INFORMATION
Your Setra transducer has been carefully calibrated before shipment to you, and it should be handled
with the same care given any precision instrument. Pressure ranges and dimensions are reported on
the specification bulletin for the transducer.
INSTALLATION
Do not use in ambient conditions corrosive to polyvinyl chloride (cable) or stainless steel, sub-
merged in liquids, subject to spray or drip, or in a high vibration environment. The 205-2 Series is
very slightly sensitive to acceleration in the pressure fitting axis, less than 0.05 psi/g typical. Fac-
tory calibrated in the vertical position, with pressure port downward, this position often minimizes
damage from dripping of pressure system piping.
Installation of pressure fitting:
For very high pressure use of sealant such as Loctite hydraulic sealant is suggested.
For other pressure ranges, standard sealants such as Teflon tape generally are satisfactory.
For the most sensitive pressure ranges, excessive high torquing of a metal pressure fitting
may cause a slight zero shift which may be trimmed out using the zero adjustment. Use of
plastic fittings often shows no noticeable zero shift. The torquing effect does not appre-
ciably affect linearity or sensitivity. Use the wrench flats on the 205-2 when attaching to
fittings.
ATMOSPHERIC REFERENCE (Gage pressure transducers only)
Lower range units are subject to excessive thermal zero shift unless vented to atmosphere. The
electrical cable provides this equalization vent.
ELECTRICAL CONNECTIONS:
CABLE LEAD FUNCTION
Red positive excitation
Green positive output
White negative output
Black negative excitation
Shield case
ELECTRICAL
The electrical circuit is equivalent to a 4 terminal network, which can be grounded at only one
point, either at the negative excitation or the negative output lead, but must not be commoned or
grounded at more than one point. The negative output lead is approximately 1.66 VDC above the
negative excitation lead. The positive output lead is at this same 1.66 VDC common mode voltage
plus the output signal from applied pressure (thus goes from approximately 1.66 VDC up to 6.66
VDC above the negative excitation).
The pressure transducer must be operated with the case connected either to the negative
excitation terminal or to the negative output terminal. Failure to do this may result in dam-
age to or unsatisfactory operation of the unit. This connection
may be made by connecting the shield to white or shield
to
black leads. Best shielding against noise will be obtained by
connecting the shield and negative excitation (black) leads.
Circuit is reversed voltage protected for at least 5 minutes.
Internal transient suppression network is provided for
short duration transients to 150 volts.
In some instances, use of long cables (sev-
er al
hundred feet length) may introduce enough cable capacitance into the