DigitalFlow™ GC868 Startup Guide (1 and 2-Channel)
1-26
Chapter 1. Installation
1.
Using the pair of coaxial cables with BNC to BNC connectors supplied by the
factory (or equivalent cables), connect both transducers to the preamplifier.
2.
If an optional lightning protector is being installed, connect it to a high-integrity
ground between the preamplifier and the electronics.
3.
Using the pair of coaxial cables with BNC to flying lead connectors supplied by
Panametrics (or equivalent cables), connect the preamplifier to terminal block
CH1
in the electronics console. Refer to Figure 1-43 on page 1-44 for the location
of the terminal block and the terminal block pin assignments.
4.
For a 2-channel Model GC868 flowmeter, repeat steps 1-3 to wire the Channel 2
transducer system to terminal block
CH2
.
Note:
It is not required that Channel 2 of a 2-channel Model GC868 be used. This
channel may be left inactive for future use.
After the wiring has been completed, the transducer channel(s) must be activated
before measurements can begin. See Chapter 2,
Initial Setup
, for instructions.
1.8.3
Wiring the 0/4-20
mA Analog
Outputs
The standard configuration of the Model GC868 flowmeter includes two isolated
0/4-20 mA analog outputs (designated as A and B). 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 1-42 on page 1-43 for the location of terminal block
I/O
and wire the
terminal block as shown.
1.8.4
Wiring the Serial
Port
The Model GC868 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).
1.8.4.1
Wiring the RS232
Interface
The RS232 communications port provides a serial interface for connecting the Model
GC868 flowmeter to a personal computer.
The RS232 serial interface is wired as Data Terminal Equipment (DTE), and the signals
available at the Model GC868
RS232
terminal block are shown in Table 1-4 below.
See Figure 1-42 on page 1-43 to locate terminal block
RS232
and complete the
following steps to wire the terminal:
1.
Use the information in Table 1-4 below to construct a suitable cable for
connecting the Model GC868 to the external device. If desired, an appropriate
cable may be purchased from the factory.
CAUTION!
As part of maintaining the FM/CSA environmental
rating (TYPE 4) on the remote preamplifier, thread
sealant is required on all conduit entries.
Table 1-4: RS232 Connection to DCE or DTE Device
RS232
Pin #
Signal
Description
DCE
DB25
Pin #
DTE
DB25
Pin #
DTE
DB9
Pin #
1
RTN (Return)
7
7
5
2
TX (Transmit)
3
2
2
3
RX (Receive)
2
3
2
