Weed Instrument 2T14 Fiber Optic Transmitter Specification Guide

 

There are two pluggable terminal blocks on the 
FOT and each has 4 screw terminal connections. 

 

POWER:  The terminal block at the top-front of the 
housing is where connection may be made for 
supplying the unit’s operating power from a 
nominal 24VDC source.  The unit may also obtain 
operating power from the Model 2A56 power 
supply module via the modules integrated Bus 
interconnections.  The Model 2A56 is a universal 
AC input power supply.  Both power sources may 
be connected to the FOT for redundancy.  The 
power connection terminals numbered from left-to-
right are as follows: 

 

 

Terminal 1 

no connection 

 

Terminal 2 

(+) plus 24VDC 

 

Terminal 3 

(-) negative 24VDC (Return) 

 

Terminal 

4 

CASE (DIN rail, chassis, 
Protective Earth Ground) 

GROUNDING: The CASE terminal and the 
negative power terminal of the FOT should always 
be connected through low impedance to Earth 
Ground. 

 

IMPORTANT NOTE:  Internally, the FOT’s 
negative (-) input terminal is connected to the 
24VDC supply negative (-) input terminal. 

 

INPUT:  The terminal block at the lower-front of the 
unit is where the connections are made to the 4 to 
20mA input signal.  The connection terminals 
numbered from left-to-right are as follows: 
 
 

Terminal 1 

no connection 

 

Terminal 2 

no connection 

 

Terminal 3 

(+) plus 4-20mA INPUT 

 

Terminal 4 

(-) negative 4-20mA INPUT 

 
OPTICAL CONNECTION:  The TX optical port on 
the front of the unit accepts an ST simplex (one) 
fiber connector and is compatible with any size of 
multi-mode glass fiber.  This fiber port generates 
the optical data information that will be passed to 
the mated Fiber Optic Receiver (FOR). 

The Model 2T14 Fiber Optic Transmitter (FOT) 
Analog Link is designed to accept a 4 to 20mA 
process signal and convert it to a fiber optic 
signal.  The mated 2R14 Fiber Optic Receiver 
(FOR) returns the signal to its original 4 to 20mA 
format. 

 

Absolutely no field adjustments are required as all 
units deliver the highest degree of accuracy over 
their entire specified ambient temperature range.  

The Model 2T14 has a green LED to indicate the 
presence of POWER.  Two separate amber LED 
indicators give visual indication that the analog 
input signal is OVER RANGE (above) or UNDER 
RANGE (below) of the normal input signal limits. 

Verify that the power supplies are on, that they 
are the correct voltage and current rating and are 
connected in the correct polarity. 

 

Verify the correct polarity connections are made 
to the INPUT and OUTPUT terminals. 

 

Measure the INPUT signal level to the FOT and 
ensure it is within the normal range. 

 

Verify the connections of the fiber optic cable are 
secure. 

 

Verify the LOCK LED is illuminated on the FOR.  
If it is not, this may indicate inadequate optical 
signal from the FOT, a broken or high loss fiber, 
or a defective FOT or FOR unit. 

 

Verify that the OVER RANGE and UNDER 
RANGE LEDs are not illuminated on either unit. 

 

If you are still experiencing difficulty, contact the 
factory for assistance.