Valve Positioners Series 74 Valve Positioners Introduction Features & Benefits Double-acting or single-acting service accommodates installation in a variety of environments Field reversibility reduces downtime and simplifies maintenance Choice of continuously adjustable standard stroke ranging from 1/4" to 48" and continuous span and zero adjustability within range spring limits provide application versatility Extra high capacity pilots ensure maximum frequency response and optimum stroking speeds for all actuator sizes Negative feedback pilot circuit allows the positioner to operate with a push-pull gain of more than 900:1 (using 3 100 psig supply) with no sacrifice in stability (gain of 650:1 with 74S models) Description The Model Series 74 Valve Positioners are universal positioners that provide versatility, dynamic performance, and high positioning accuracy. They use the piston or diaphragm in a pneumatic actuator to position a valve to what is required by a control instrument and hold that position, regardless of the presence of forces that change valve position. As such, supply pressure variations have little Overload Protection or no effect on the positioner output, which eliminates the 150 psig at any connection need for a supply pressure regulator. Response Level These valve positioners are two-stage, pilot-operated instruments. The pilot circuit activates dual-output boost- Output is sensitive to control signal changes as small as ers, which perform opposite actions (when one booster is 0.1% of full range supplying air, the other is exhausting air.) This “push-pull” Ambient Temperature Range action applies to a full differential (supply pressure to atmosphere) across the actuator to drive the valve to the -40 to 180°F (-40 to 82°C) position required by the control instrument signal. Materials of Construction Model 74 Valve Positioners can also be used for single- Aluminum, brass, stainless steel, and Buna-N acting service on a spring-loaded actuator. In this case, one of the pilot-booster connections is plugged. See below for Rotary Actuators Kit rotary-type actuators. The Series 74 Rotary Actuator Kits allows for compact instal- lation of a complete assembly (positioner and mounting) to fit inside a 5"x 5"x2-2/3" envelope. The kit’s direct connected Specifications feedback spring eliminates error-prone connections and Input Ranges levers, while its spiral feedback spring provides inherent reliability. 3-15, 3-9, 3-27, 0-15, and 0-30 psig including split ranges within these basic ranges Response Level 1 Valve-Stroke Ranges 0.1% F.S. 1/4" minimum Linearity 48" maximum ±1.5% F.S. Supply Pressure Input Range 3 psig above full actuator pressure minimum 2 3-9, 9-15 , 3-15 psig 150 psig maximum Actuator Motion Air Consumption 90° Rotation 0.2 scfm (in balanced condition with 20 psig supply) 1) See next page for additional performance data, design specifications, and a range spring selection chart. 2) 9-15 psig range requires a suppression spring. 3.9 Valve Positioners Series 74 Valve Positioners Ordering data Model Number Accessories Order No. Rectilinear Range Spring Kits - Rectilinear range spring kits Valve Positioner 74- include a range spring, zero screw, (2) range spring seats, ■■■ Sensitivity and instructions. All kits include the (2) range spring seats, ▲ ▲ ▲ Standard Pilot & Standard Gain P/N 12372-384 (not listed below). • Stabilizing Pilot & Reduced Gain S Rotary Range Spring Kits - The table below lists the kit Gauge Option numbers, spring assembly numbers, and their color codes. • With 3 Gauges G • Without Gauges N Zero Suppression Spring Kits - Zero suppression spring kits Intermediate Sensitivity include a suppression spring and a spring seat. All kits • Standard Pilot & Reduced Gain 1 include the P/N 12372-254 spring seat (not listed below). (74S only) 3 Range Spring Kit Table Instrument Input Pressure Range - psig Acutator Kit Stroke and - Inches - Parts 3-15 3-9 3-27 0-30 0-15 1/4 to 1-1/2 Kit No. 14995-101 14995-114 14995-104 14995-107 14995-110 Spring No. 14996-1 14996-4 14996-7 14996-10 14996-13 Color Code Black Black-Red Black-Yellow Black-Orange Black-Green Screw No. 12372-274 12372-274 12372-274 12372-274 12372-274 1-1/2 to 2-3/4 Kit No. 14995-102 14995-115 14995-105 14995-108 14995-111 Spring No. 14996-2 14996-5 14996-8 14996-11 14996-14 Color Code White White-Red White-Yellow White-Orange White-Green Screw No. 12372-273 12372-273 12372-273 12372-274 12372-274 2-3/4 to 4 Kit No. 14995-103 14995-116 14995-106 14995-109 14995-112 Spring No. 14996-3 14996-6 14996-9 14996-12 14996-15 Color Code Blue Blue-Red Blue-Yellow Blue-Orange Blue-Green Screw No. 12372-273 12372-273 12372-273 12372-292 12372-273 4 to 6 Kit No. 14995-119 Spring No. 14996-102 Consult Siemens Color Code Brown Screw No. 12372-292 6 to 9 Kit No. 14995-117 14995-128 14995-126 Spring No. 14996-104 14996-16 14996-107 Consult Siemens Color Code Green Brown-Red Green-Yellow Screw No. 12372-292 12372-303 12372-303 9 to 12 Kit No. 14995-120 14995-129 14995-127 Spring No. 14996-106 14996-17 14996-108 Consult Siemens Color Code Red Yellow-Red Green-Red Screw No. 12372-3034 12372-303 12372-303 12 to 19 Kit No. 14995-118 Spring No. 14996-110 Consult Siemens Color Code Orange Screw No. 12372-303 48 Kit No. 14995-121 Spring No. 14996-111 Consult Siemens Color Code None Screw No. 12372-296 3.10 Valve Positioners Series 74 Valve Positioners Technical data Rotary Range Spring Kit Rotation of Actuator Shaft Clockwise Counterclockwise Instrument Input Range -psig- 3-9 3-15 3-9 3-15 Kit Supplied Kit No. 14923-152 14923-154 14923-102 14923-104 Without Spring No. 14923-72 14923-70 14923-73 14923-71 Mounting Plate Color Code Green White Black Red Kit Supplied Kit No. 14923-151 14923-153 14923-101 14923-103 3 With Spring No. 14923-72 14923-70 14923-73 14923-71 Mounting Plate Color Code Green White Black Red Mounting Dimensions Mounting Dimensions, Rotary Kit The actuator extension shaft must be 0.3125" ±0.0010" and capable of withstanding 100 inch-pounds of torque (pinned assembly recommended). Installer to drill and mount the base plate so that the appropriate feedback hole (clockwise or counter-clockwise rotation) is concentric with actuator extension shaft. 3.11