Panametrics CTF878, Startup Manual

Page: 42 / 108

Chapter 2.
34 Model CTF878 Startup Guide
2.1.13 PC Board Connections
2.1.13.1 Wiring the 0/4-20 mA Analog Outputs
The standard configuration of the CTF878 flowmeter includes two isolated 0/4-20 mA analog outputs (designated as
1 and 2). Connections to these outputs may be made with standard twisted-pair wiring. The current loop impedance
for these circuits must not exceed 550 ohms. Refer to Figure 25 on page 40 for the location of the Analog Output
terminal block and wire the terminal block as shown.
2.1.13.2 Wiring the Serial Port
The CTF878 is equipped with a built-in serial communications port. The standard port is an RS232 interface, but an
optional RS485 interface is available upon request. Proceed to the appropriate sub-section for wiring instructions. For
more information on serial communications, refer to the EIA-RS Serial Communications Manual (916-054).
Wiring the RS232 Interface
The RS232 serial communications port may be used for connecting the CTF878 flowmeter to a personal computer.
The RS232 serial interface is wired as Data Terminal Equipment (DTE), and the signals available at the flowmeter’s
RS232 Serial Port terminal block are shown in Table 1 below. Refer to Figure 25 on page 40 to locate terminal block
RS232 and complete the following steps to wire the terminal:
1. Use the information in Table 1 below to construct a suitable cable for connecting the CTF878 to the external
device. If desired, an appropriate cable may be purchased from the factory.
2. Disconnect the main power to the unit and open the cover on the electronics enclosure. Remove the plastic
shroud to access the serial communication connector.
3. Wire the flying leads end of the cable to terminal block RS232 and connect the other end of the cable to the
printer, ANSI terminal or personal computer.
Table 1: RS232 Connections to a PC (DCE Device)
RS232
Pin #
Signal
Description
DCE DB9
Pin #
1 RTN (Return) 5
2 TX (Transmit) 2
3 RX (Receive) 3
4 DTR (Data Terminal Ready) 4
5 CTS (Clear to Send) 7