Turb 2000 Series
Installation and commissioning
ba75695e03 10/2013
15
2.3.2 4-20
mA
CAUTION
Do not run RS-485 cables in the same conduit as power.
To prevent damage to the instrument, ensure that power is
disconnected prior to connecting the 4-20 mA output.
For ease of connecting, remove the plug in terminal block. Polarities of the connections are labeled
beneath this termination.
The 4-20 mA output is driven by a 15 V DC power source and can drive recorder loads up to
600 ohms. This 4-20 mA output is isolated from line power and earth ground. Operation of this output is
covered in section 6.2 S
ETTING THE
4-20
M
A.
Note
The installation of the 4-20 mA terminal block will render the RS-485 non-operational.
2.3.3 RS-485
The RS-485 half-duplex (2-wire) digital interface operates with differential levels that are not susceptible
to electrical interferences. This is why cable lengths up to
3000 ft can be implemented. The last device on each bus may require terminating with a
120-ohm resistor to eliminate signal reflection on the line.
CAUTION
Do not run RS-485 cables in the same conduit as power.
To prevent damage to the instrument, ensure that power is
disconnected prior to making connections.
Pull the plug off the circuit board to make connecting easier. Connections are labeled beneath this
termination.
Note
The installation of the RS-485 interface will render the 4-20 mA terminal block non-
operational.
2.3.4 Relays
The Alarm 1 and Alarm 2 relays are mechanical relays rated at 240 V AC
2A. Please note that the relays are labeled NO (Normally Open),
NC (Normally Closed) and C (Common). As these alarms are configured fail-safe, the normal condition
is with power applied to the Turb 2000 series and in a non-alarm condition. Operation of these alarms is
covered in section 6.5 C
ONFIGURING THE ALARMS
.
Summary of Contents for Turb 2000 Series
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