Setra System Model 470 - Manual (Page 5)

5
SECTION TWO
Installing the Model 470
2.1 Power Connections
The Setra 470 requires a 5 volt DC power supply regulated to
±
1% which can supply 90 milliamps
of current. Use of a correctly rated and regulated power supply is important for correct operation
of the digital electronics in the Setra 470.
To apply power to the Setra 470, follow these steps:
1. Connect a DB9P (D-Subminiature 9 pin male connector) to a cable from the
5 VDC power supply with the following pinout:
Pin 3 is connected to power supply ground.
Pin 9 is connected to +5 VDC.
All other pins are not connected.
2. Locate the DB9S power connector on the Setra 470. It is a 9 pin D-Subminiature female
connector to the right of the pressure port and is marked “Power” on the label.
3. Insert the male connector on the power supply cable into the female connector on the
Setra 470 and secure it by tightening the mounting screws on the male connector into the
flanges on the female connector.
4. In some installations there is a requirement for the case of the transducer to be grounded
to or through a shield. The Setra 470 case is connected internally to power supply ground
and therefore must not be connected to any other ground.
5. Turn on the power supply.
2.2 Pressure Connections
The pressure connection on the Setra 470 is a standard 1/8” diameter barbed hose fitting, 1/2” in
length. You can remove this fitting and install a different fitting in the
10-32 threaded female port.
The Setra 470 transducer is designed to measure the pressure of clean, dry, nonconducting,
noncorrosive gases only.
The Proof Pressure of the Setra 470 (the maximum pressure which can be applied without
disturbing the calibration of the transducer) is 150% of the full scale pressure. To ensure that the
pressure applied to the transducer does not exceed the proof pressure, install properly rated relief
valves in any system this unit is connected to.
2.3 Communications Hardware
The Setra 470 is equipped with a standard bidirectional RS-232 communications port. The RS-
232 Communications Standard describes in detail the requirements and conventions of RS-232.
The Setra 470 implements a very simple subset of the standard, and does not provide handshak-
ing lines (such as DSR, CTS, or DTR).
The Setra 470 RS-232 serial interface is a DTE type (Data Transmission Equipment). This
means that it receives data on pin 3 and transmits data on pin 2. This is in contrast to DCE (Data
Communication Equipment) which receives data on pin 2 and sends data on pin 3. Because the
RS-232 Standard describes communications between DTE and DCE devices, the host device
you connect to the Setra 470 (computer terminal, or data acquisition system) must have a pinout
which correctly corresponds to the Setra 470 pinout.