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4200 Transmitters
September 2022
1. To provide an indication of switch condition, remove power from the instrument. Connect an ohmmeter to TB2
between the (NC) and (C) terminals (figure 4).
2. Stroke the device to the point of travel where the low position switch is to operate (See figure 7).
3. Apply power to the instrument.
4. Ensure that the low position switch potentiometer (LOW, R6, figure 5) is fully counterclockwise as previously
instructed.
5. Turn the low position switch potentiometer (R6) slowly clockwise until the low position switch trips, the ohmmeter
changes from a high to a low resistance reading.
6. The low position switch is now set.
Setting the Low Position Switch Deadband
1. Slowly stroke the actuator or device between the tripped and reset point of the low position switch. Observe this by
the changing readings on the ohmmeter. Note the differences in travel between the trip point and reset points. This
is the deadband of the low position switch.
2. If necessary, increase the deadband, by turning potentiometer (DBL, R5, figure 5) clockwise.
3. Repeat steps 1 and 2 until the desired deadband setting is obtained.
4. If adjustments are complete, remove power from the instrument and disconnect the ohmmeter.
5. Perform the installation and/or operating procedures to place the transmitter in service and replace the transmitter
covers. Be sure to tighten the set screws (key 106) securely after installing the covers.
Position Switch Circuit Shutoff
Refer to figure 5 for location of adjustments.
Certain conditions may require the position switch circuit capabilities to be shut off. To shut off the position switches,
turn the high position switch potentiometer (HIGH, R3) fully clockwise, and turn the low position switch
potentiometer (LOW, R6) fully counterclockwise. To restore the position switch circuits to operation, follow the high
and low position switch adjustment procedures described in this section.
Note
Both position switch relays are energized in this condition. The trip points cannot be adjusted to prevent the relays from
energizing.
Principle of Operation
The basic concept of the electronic position transmitter can be understood by visualizing the entire transmitter as a
variable resistor in series with a load and connected to a power supply as shown in figure 9. A linkage or travel
transducer assembly transmits linear motion of the device into rotary motion of the potentiometer. The
potentiometer is connected to the input of the transmitter circuit. The voltage present at the wiper of the
potentiometer supplies input voltage to the electronic circuitry in the transmitter to produce a current output.
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Instruction Manual
D200354X012
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