High And Low Position Switch Adjustment - Emerson Fisher 4210 Instruction Manual

Instruction Manual
Form 5596
November 2006
2. Connect the transmitter as shown in figure 8.
3. Remove the transmitter covers.
4. Stroke the valve or device to the mid-stroke
position
5. Check the potentiometer alignment by connecting
a digital voltmeter (DVM) as follows:
a. For all transmitters (except a Type 4212 or
4222) connect between TP3 (+) and TP4 (−) on
the printed wiring board.
b. For a Type 4212 or 4222 transmitter, connect
the DVM between TP5 (+) and TP6 (−).
6. Apply power to the instrument.
7. The DVM should read 1.25 ±0.05 volts dc. If not,
perform the potentiometer alignment procedures in
the Installation section.
8. Stroke the valve or device to the point of travel
where the transmitter output is to be 4 milliamperes
dc.
9. Adjust the zero potentiometer (R1, figure 5) until
the output is 4 milliamperes dc (1.00 volt across 250
ohms).
10. Stroke the valve or device to the point of travel
where the transmitter output is to be 20 milliamperes
dc.
11. Adjust the span potentiometer (R2, figure 5)
until the output is 20 milliamperes dc (5.00 volts
across 250 ohms).
12. Some small interaction between the two
adjustments may occur. Repeat steps 8 through 11
until the error is within the application requirements.
13. For a Type 4211 or 4221 transmitter without
position switches, calibration is complete. Refer to
the installation and/or operating information to place
the transmitter in service.
14. If calibration is complete, replace the transmitter
covers. For transmitters with position switches, refer
to the high and low position switch adjustment
procedure below.
4200 Series Transmitters
High and Low Position Switch
Adjustment
The "high" and "low" designations
refer to the voltage output of the
position potentiometer. See figure 7
for relationship to valve or actuator
travel.
The high position switch must be
adjusted before the low position
switch. If the deadband of either the
high or low position switches exceeds
the difference between the set points
of the high and low position switches,
both position switches may be on at
the same time.
The following procedure sets the high and low
position switches, and the deadband for each of
them. The high position switch must be adjusted
before the low position switch. Use an ohmmeter
connected between the normally closed (NC) and
common (C) connections on terminal block TB1
(high switch) or TB2 (low switch) to observe relay
switching action as directed by the procedures.
The potentiometer alignment procedures must be
performed before calibrating the position switch
circuits. For transmitter and position switch switch
conditions, refer to figure 7 while performing the
following calibration:
1. If necessary, perform the potentiometer
alignment procedure.
2. Remove power from the instrument.
3. Remove the transmitter covers.
4. To provide an indication of switch conditions,
remove power from the instrument. Disconnect the
position switch field wiring from TB1 and TB2, and
connect an ohmmeter to TB1 between the (NC) and
(C) terminals (figure 4).
Turn both the high and low deadband
potentiometers (DBH, R4, and DBL, R5) fully
counterclockwise to set the deadbands to minimum
and set the low position switch potentiometer (LOW,
R6) fully counterclockwise.
Note
19