Transmitter And Position Switch Conditions; Normal Operation - Emerson Fisher 4200 Instruction Manual

Instruction Manual
D200354X012
If the transmitter is calibrated for a specific control valve actuator travel, perform the procedures in the Calibration
section to fine tune the zero and span adjustments to the specific application.

Transmitter and Position Switch Conditions

D A 4210 or 4220 transmitter (with position switches) obtains stem position from the input potentiometer and circuit
electronics to provide a 4 to 20 milliampere output. The transmitter output connects to a terminal block mounted
in the field wiring compartment. The high position switch circuit output controls relay K1 mounted on the field
circuit printed wiring board, and the relay contacts connect to TB1. The low position switch circuit output controls
relay K2, and the relay contacts connect to TB2. The relationship between the transmitter output, relay position
switch outputs, and deadband is shown in figure 7. Deadband is the difference between trip and reset points of a
relay.
D A 4211 or 4221 transmitter (without position switches) obtains input information from the potentiometer and
provides a 4 to 20 milliampere output. The transmitter output connects to the barrier strip (key 11, figure 4)
mounted in the field wiring compartment.
D A 4212 or 4222 position switch (without the transmitter) obtains stem position from the input potentiometer and
provides position switch outputs from relays K1 and K2 (figures 4 and 9). The high position switch circuit output
controls relay K1 mounted on the field circuit printed wiring board and, the relay contacts connect to TB1. The low
position switch circuit output controls relay K2 and, the relay contacts connect to TB2. Deadband is the difference
between trip and reset points of a relay.
D A 4215 transmitter obtains position information from a dual potentiometer on the same shaft, which allows for
individual potentiometers for the transmitter circuit and the position switch circuits. The transmitter input is from
one of the potentiometers and its output connects to TB3 (figure 6) mounted on the field circuit printed wiring
board. The position switch input is obtained from the other potentiometer.
The high position switch circuit output controls relay K1 mounted on the field circuit printed wiring board and the
relay contacts connect to TB1. The low position switch circuit output controls relay K2 and the relay contacts connect
to TB2. The relationship between the transmitter output, relay position switch outputs, and deadband is shown in
figure 7. Deadband is the difference between the trip and reset points of a relay.

Normal Operation

WARNING
On an explosion‐proof instrument, remove electrical power before removing the instrument covers in a hazardous area.
Personal injury or property damage may result from fire or explosion if power is applied to the instrument with the covers
removed, in a hazardous area.
Once the instrument has been calibrated and placed in operation, further adjustments should not be necessary. The 4
to 20 milliampere output can be monitored during operation (in a non‐hazardous environment) by removing the
cover and connecting a milliammeter between TP1 (+) and TP2 (-) on the printed wiring board (figure 5) on 4210,
4211, 4215, 4220, or 4221 transmitter. On 4212 or 4222 connect a voltmeter between TP5 (+) and TP6 (-) to measure
potentiometer position.
For position switch circuits, the switching condition can be monitored by observing the indicating device or using an
ohmmeter connected to the terminal blocks (TB1 and TB2) in the field wiring compartment. Refer to the Calibration
section for the test setup.
4200 Transmitters
March 2011
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