Flowserve XL Series High-Performance Positioner - Manual (Page 7)

45-7 Flowserve Corporation, Valtek Control Products, Tel. USA 801 489 8611
1. Connect the I/P module to a supply pressure be-
tween 30 to 150 psi.
2. Remove I/P module housing cover. (See Figure 10.)
WARNING: Be certain power to the I/P module is
disconnected before removing the housing
cover in explosive atmospheres; otherwise per-
sonal injury may occur.
3. Before adjusting the zero and span, be certain the
MPC feature is disabled. Refer to Step 7 in the
‘Adjusting the Minimum Pressure Cutoff Feature’
section.
4. Connect a current source to the terminal block on
the circuit board.
NOTE: The zero and span adjustments are
multi-turn potentiometers (pots) that have no
stops on the ends of their travel; however, they
have a slip clutch to prevent damage from over-
adjustment. The pots also make a clicking
noise when they have reached the limits of their
adjustment.
5. Apply a 4.0 mA signal to the input. Locate and
adjust the zero trim pot to achieve a 3.0 psi output.
Output will increase with clockwise rotation of zero
trim pot. If calibrating an I/P module with a 10-50 mA
input signal, apply a 10.0 mA signal to the input.
6. Increase the input signal to 20.0 mA (50 mA for 10-
50 mA units). Locate and adjust the span trim pot to
achieve a 15.0 psi output. The output will increase
with clockwise rotation of the span.
7. Recheck the zero setting by repeating Step 5. The
span adjustment may affect the zero setting.
8. Repeat Steps 5, 6 and 7 until the proper adjust-
ments are obtained.
Adjusting the Minimum Pressure Cutoff
Feature
The XL positioner with I/P Transducer has a ‘Minimum
Pressure Cutoff’ (MPC) feature, which allows the user
to set the positioner so when the input signal falls below
a user-adjustable current the pressure output falls rap-
idly to approximately 1.7 psi, causing the valve to move
to the failure position. This feature is generally used
when the service requires a tight shut off or to prevent
throttling near the valve seat. To adjust this feature,
refer to Figure 10 and perform the following steps:
NOTE: The following procedure applies only if the
minimum pressure cutoff feature will be used.
NOTE: The zero and span settings of both the
positioner and I/P transducer should be verified as
accurate before the minimum pressure cutoff fea-
ture is enabled and adjusted.
1. Connect the I/P module to a 30 to 150 psi air supply
pressure.
2. Remove the I/P module housing cover.
WARNING: Be certain power to the I/P module is
disconnected before removing the housing
cover in explosive atmospheres; otherwise per-
sonal injury may occur.
3. Connect an adjustable current source to the termi-
nal block on the circuit board. Apply the desired
input signal to the positioner at which the output
pressure is to fall to approximately 1.7 psi. This
signal can range from factory setting of 3.7 to 8 mA.
4. Turn the minimum pressure cutoff pot clockwise
until the output pressure drops off.
5. Fine-tune the pressure drop-off point by increasing
the input signal and then decreasing it through the
desired shut-off signal. Observe the signal value at
which the pressure drops off. If the pressure drops
off at a lower mA signal than desired, turn the MPC
pot slightly counterclockwise. If the pressure drops
off at a higher signal than desired, turn the tight
shut-off screw slightly clockwise.
6. Repeat Step 5 until the pressure drops off at the
desired input signal.
7. To disable the MPC feature turn the minimum
pressure cutoff pot (marked ‘MPC’) 20 turns coun-
terclockwise or until it makes a clicking noise.
Positioner Maintenance
NOTE: Refer to NT 3000 IOM for I/P module mainte-
nance instructions.
For proper maintenance, proceed as follows:
1. Maintain a clean air supply, free of dust, oil and
water. A coalescing air filter for I/P is required to
ensure a clean air supply. Check and maintain filter
regularly.
2. Make sure all arms and levers move freely.
3. Check for any loose parts.
4. Be sure there are no leaks in the air supply tubing
fittings or connections.
5. Refer to the troubleshooting chart on page 12 in
case of problems.
NOTE: The two Phillips screws on the back of
the positioner base are for factory assembly
only and should not be removed.
Pilot Relay Disassembly and Reassembly
The pilot relay is available as a complete unit and can
be easily replaced. (See Steps 2 and 18.) Before
attempting to correct any problem with the pilot relay
assembly, obtain a positioner repair kit that contains the
soft goods most commonly required.
NOTE: Numbers in parentheses correspond to the
numbers in Figure 17.