3200Md Digital Pneumatic Valve Positioner Auto Tuning With Dynamic Gain Selection

• Local status LED's
• Local DIP Switches/Calibration Buttons
• Auto Tuning with dynamic gain selection
• Utilizes HART 5
• Simple calibration via local interface

• Explosion proof enclosure rated Class I Division 1 Groups B-D, Ex d IIB+H2, AEx d IIB+H2
• Intrinsically Safe Rated Class I, Div 1, Groups A-G, Ex ia IIC, AEx ia IIC
• Non-Incendive Class I Div 2 A-D, Ex nA
• SIL 2

Specifications

The Logix 3200MD positioner is an electric feedback instrument. Figure 1 shows a Logix 3200MD positioner installed on a double-acting linear actuator for air-to-open action. The Logix 3200MD receives power from the two-wire, 4-20 mA input signal. However, since this positioner utilizes HART communications, two sources can be used for the command signal: Analog and Digital. In Analog source, the 4-20 mA signal is used for the command source. In Digital source, the level of the input 4-20 mA signal is ignored and a digital signal, sent via HART, is used as the command source. The command source can be accessed with ValveSight software, the HART 375 communicator, or other host software. Whether in Analog or Digital Source, 0% is always defined as the valve closed position and 100% is always defined as the valve open position. In Analog Source, the 4-20 mA signal is converted to a percentage. During loop calibration, the signals corresponding to 0% and 100% are defined.

A more detailed example explains the control function. Assume the unit is configured as follows:

• Unit is in Analog command source.

• Custom characterization is disabled (therefore characterization is Linear).

• No soft limits enabled. No MPC set.

• Valve has zero deviation with a present input signal of 12 mA.

• Loop calibration: 4 mA = 0% command, 20 mA = 100% command.

• Actuator is tubed and positioner is configured air-to-open

Note: The air supply must conform to ISA Standard ISA 7.0.01 (a dew point at least 18 degrees Fahrenheit below ambient temperature, particle size below five microns—one micron recommended—and oil content not to exceed one part per million).