Electrical Information For Standard 24 Vdc Excitation Pressure Transducers; Electrical - Setra Systems 204 Operating Instructions Manual

2.0 Electrical information for standard 24 VDC excitation
pressure transducers (nominal)
Connections (Model 204, 239; electrical termination Y1, Y4, Y4, Y6) Red Cable
Cable Lead
White
Yellow
Brown
Black
Shield
Notes:
Other leads in the cable are not used with the standard pressure transducer unless
the transducer has been wired for Remote Control (see Remote Control Instructions)
Connections (Model 204, 239; electrical termination 02, 10, 25) Gray Cable
Cable Lead
Red
Black
White
Green
Shield

2.1 Electrical

The electrical circuit is equivalent to a 4 terminal network, which means negative excitation
lead shall not be connected to negative signal output lead.
The pressure transducer must be operated with the case connected to earth ground to meet
EMC requirement. Best performance will be achieved by connecting the shield and negative
excitation lead if it is feasible and allowed.
The circuit has internal protection:
• Reversed excitation voltage for at least 5 minutes.
• Short-circuit or signal output leads.
• Short duration power line transients up to 150 volts.
Note on long cable use
In some instances, use of long cables (several hundred feet length) may introduce enough
cable capacitance into the circuit to cause output oscillations. If encountered, this oscillation
may be eliminated by connecting a 100 ohm resistor (1/8th watt or larger) in series to each of
the output leads at the end of the 2 foot transducer cable. These series resistors, of course,
add to the output resistance.
Atmospheric reference (Gauge pressure transducers only)
Lower range units are subject to excessive thermal zero shift unless vented to atmosphere.
The electrical cable provides this equalization vent. Do not seal the electrical cable when
installing.
Function
Function
5
Positive excitation
Positive output
Negative output
Negative excitation
Case
Positive excitation
Negative excitation
Negative output
Positive output
Case