Emerson Process Management Bristol Series 9110 - Manual (Page 11)

CI-9110 1-1 Introduction
Chapter 1
INTRODUCTION
1.1 PRODUCT DESCRIPTION
Series 9110-00A, Remote Set Regulators are transducer devices that use an electrical input
signal to set the level of a pneumatic output signal. Depending on the actual model, the
electrical input may be either an analog or a raise/lower type signal. For analog models, the
input can be configured for a 1-5 V dc or 4-20 mA dc signal. For the Raise/Lower models,
the input can be configured to accept a continuous or pulse incremental dc signal.
The pneumatic output of a Remote Set Regulator may be specified with a 3-15, 3-27 or 6-30
psi output. All models can operate from pressure supplies up to 100 psi (Max). Minimum
supply pressure must be at least 3 psi above the maximum range value.
The Regulator also provides a guard input. This signal can be used to Enable (turn ON) or
Inhibit (turn OFF) the input for telemetry and security applications. When the guard signal
is Enabled, it allows the output to respond to a change of the input signal.
The Remote Set Regulator is contained in a weatherproof, explosion-proof enclosure having
a detachable threaded cover. Removal of the cover provides access to the field wiring
terminals and the programmable option switches.
Regulators are factory-furnished for 12 Vdc or 24 Vdc supply operation. These voltage
ratings are fixed and cannot be changed in the field.
In-line or pipe mounting are offered as for installations. The former uses a 1/4 inch rigid
pressure line for support, while the latter includes a special bracket for two-inch pipe
mounting.
1.2 THEORY OF OPERATION
The Remote Set Regulator contains a CPU Board and a Termination Board. The CPU
Board contains the central processor and its associated circuitry, while the Termination
Board contains the field wiring terminals and the input protection circuitry.
The Regulator is offered in Analog and Raise/Lower models. Both types use similar
circuitry but they perform different functions. A description of the Analog model follows
while the Raise/Lower model is explored later in the text.
1.2.1 Analog Regulator Model
The Analog Regulator circuitry is shown in the block diagram of Figure 1-2. In this circuit,
the Command signal (1-5 V or 4-20 mA) is applied to a buffer amplifier which drives the
plus (+) input of the Lower Comparator and the minus (-) input of the Raise Comparator.
Also note that the opposing inputs of both comparators are referenced to the same point
which is the center arm of a feedback pot.