Johnson Controls System 350T A350P User Manual

FANs 930, 930.5, 125, 121
Product/Technical Bulletin A350P
Issue Date 0414
© 2014 Johnson Controls, Inc. 1
Part No. 24-7664-192, Rev. G www.johnsoncontrols.com
Code No. LIT-930020
The A350P is an electronic, proportional plus integral
temperature control with analog 0 to 10 VDC and
0 to 20 mA outputs. The control is equipped with
three user-selectable time integration constants and
an adjustable throttling range of 2 to 30F° (1 to 17C°).
Two models cover a setpoint range of -30 to 130°F
(-35 to 55°C) and 90 to 250°F (32 to 121°C).
As are all System 350
™
products, the A350P control
is housed in a NEMA 1, high-impact plastic enclosure.
The modular design provides easy, plug-together
connections for quick installation and future
expandability.
Figure 1: A350P Electronic Proportional Plus
Integral Temperature Control
Features and Benefits
 Modular Design Enables stage, display, and power modules to
be purchased and installed as needed
 Plug-Together Connectors
and 35 mm DIN Rail
Mounting
Eliminates wiring between modules, which
reduces installation costs
 Two Models Cover a Wide
Setpoint Range of -30 to
250°F (-35 to 121°C)
Reduces inventory by encompassing
temperature ranges required to support the
majority of Heating, Ventilation, Air Conditioning,
and Refrigeration (HVAC/R) applications
 Minimum Output Adjustable
from 0 to 60%
Tailors the output to the requirements of the
controlled device; can be used to set minimum
valve or damper position
 Adjustable Throttling
Range of 2 to 30F° (1 to 17C°)
Enables the user to tune the system for optimum
stable performance
 Field-selectable Reverse
or Direct Acting Mode
Works in heating or cooling applications
 Three User-Selectable
Integration Time Constants
Provides selection of the integration constant for
applications requiring proportional plus integral
control
 Interchangeable
Temperature Sensors
Increase versatility and serviceability
System 350
TM
A350P Electronic Proportional Plus Integral
Temperature Control

Johnson Controls System 350T A350P Specifications

General

Brand	Johnson Controls
Model	System 350T A350P
Category	Temperature Controller
Language	English

Summary

Features and Benefits

Modular Design

Enables stage, display, and power modules to be purchased and installed as needed.

Plug-Together Connectors and DIN Rail Mounting

Eliminates wiring between modules, reducing installation costs.

Wide Setpoint Range

Covers -30 to 130°F and 90 to 250°F for HVAC/R applications.

Minimum Output Adjustment Feature

Allows tailoring output to device requirements or setting minimum valve/damper positions.

Adjustable Throttling Range Feature

Enables tuning for optimum stable performance, adjustable from 2 to 30F°.

Field-Selectable Acting Mode Feature

Supports both heating and cooling applications via Reverse or Direct Acting mode.

User-Selectable Integration Time Constants Feature

Provides selection of integration constants for P+I control applications.

Interchangeable Temperature Sensors

Increases versatility and serviceability of the control system.

Application

Operation Features

Adjustable Setpoint

Allows user to set the desired temperature point for control.

Adjustable Minimum Output Setting

Sets the minimum output level for the controlled device.

Adjustable Throttling Range Setting

Determines the range over which the control's output changes.

Selectable Integration Time Constant Setting

Allows tuning of the integral response for system stability.

Selectable Acting Mode Setting

Defines how the output responds to temperature changes relative to the setpoint.

Minimum Output Adjustment Procedure

Throttling Range Adjustment

Integration Function Explained

Integration Function Details

Proportional vs. P+I Control Comparison

Compares control types, explaining proportional offset and system error.

Integral Windup Avoidance Mechanism

Describes A350P's patented circuit to prevent integral windup and overshoot.

Integration Constant Selection Options

Details selectable constants (Slow, Medium, Fast) and OFF mode for integration.

Reverse or Direct Acting Operation Explained

Add-on Module Overview

S350A On-Off Stage Modules

Modules for switching functions based on setpoint and sensor information.

S350C Slave Stage Module

Modules for switching functions based on sensor info, setpoint, and differential.

S350P Proportional Stage Modules

Modules that respond with analog output based on control parameters.

Dimensions and Mounting

Installation and Wiring Guidelines

Celsius Scale Conversion

Instructions for applying the Celsius scale throttling range decal.

Electrical Safety Warning

Warns about electrical shock hazards during installation and wiring.

Wiring Terminals and Connections

Sensor Connection Guidelines

A350P Control Adjustments

Setting RA/DA Operation Jumpers

Procedure for setting the Reverse Acting (RA) or Direct Acting (DA) mode.

Adjusting Throttling Range Potentiometer

Procedure for setting the throttling range potentiometer.

Setting Minimum Output Potentiometer

Procedure for adjusting the minimum output potentiometer using LEDs or voltmeter.

Checkout Procedure Steps

Steps to verify the A350P control is connected and functioning properly.

Troubleshooting Initial Voltage Checks

Initial checks for proper voltages (24V and 5V) on the A350P control.

Troubleshooting Voltage and Sensor Checks

Verifying 5 VDC Power Supply

Checks the 5 VDC supply to the A350P control using a DVM.

Checking Sensor Resistance Against Temperature

Measures sensor resistance against temperature charts for proper function.

A350P Control Operation Checks

Repairs and Replacement Information

Ordering Information for System 350 Products

Technical Specifications