Programmable Plant Control Unit (PPCU) Technical Requirements

This article is about general and technical requirements for Programmable Plant Control Unit (PPCU) used in Integrated Automation System or Building Automation System.

Programmable Plant Control Unit (PPCU) Technical Requirements

  1. HVAC PPCU controllers shall be fully programmable to meet the unique requirements of the facility it shall control. The controller platform shall provide options and advanced system functions, programmable and configurable using Niagara 4 Framework, that allow standard and customizable control solutions required in executing the “Sequence of Operation”.
  2. All PPCUs shall be application programmable and shall always maintain their certification. All control sequences within or programmed into the PPCU shall be stored in non-volatile memory, which is not dependent upon the presence of a battery to be retained.
  3. The PPCUs shall be capable of daisy-chain IP communications with other PPCU’s and peer-to-peer communications with SNC’s and with any OWS connected to the BAS, whether the OWS is directly connected, connected via cellular modem or connected via the Internet.
  4. The communication protocols utilized for peer-to-peer communications between PPCU’s will be Niagara 4 FoxS or BACnet TCP/IP. Use of a proprietary communication protocol for peer-to-peer communications between PPCU’s is not allowed.
  5. The PPCU shall be licensed and enabled to support five (5) devices and shall be licensed with the following Open protocol drivers by default:
    • BACnet (MS/TP and IP [ISO 16484-5])
    • LonTalk (ISO 14908)
    • MODBUS (RTU and TCP)
  6. The PPCU shall be provided with a 1 Year Software Maintenance license. Labor to implement not included if greater than 1 year is required.
  7. The PPCU shall provide LED indication of communication and controller performance to the technician, without cover removal.
  8. The PPCU shall be capable of executing application control programs to provide:
    • Calendar functions.
    • Scheduling
    • Trending
    • Alarm monitoring and routing.
    • Time synchronization.
    • Integration of all daisy-chain PPCU’s.
    • Network management functions for all daisy-chain PPCU’s.
  9. Programming software shall be embedded into the PPCU. The PPCU shall not require any external configuration tool or programming tool. All configuration and programming tasks shall be accomplished and accessible from within the embedded Niagara 4 environment.
  10. The PPCU shall support the following security functions.
    • Module code signing to verify the author of programming tool and confirm that the code has not been altered or corrupted.
    • Role-Based Access Control (RBAC) for managing user roles and permissions.
    • Require users to use strong credentials.
    • Data in Motion and Sensitive Data at Rest be encrypted.
  11. The PPCU shall provide the following hardware features as a minimum:
    • Two 10/100 Mbps Ethernet port.
    • Two RS-485 ports, one isolated and one non-isolated, with biasing switches.
    • ARM 9 32-bit processor, 1 GHz
    • 1 GB RAM
    • 512 KB MRAM
    • 4 GB Flash Memory
    • Two USB 2.0 ports
    • One HMI port to connect onboard or remote HMI.
    • 0-50 degrees C Ambient Operating Temperature
    • Integrated 24 VAC/DC Global Power Supply
    • Real Time Clock
  12. The PPCU shall support standard Web browser access via the Intranet/Internet.
  13. The PPCU shall be able to route any alarm condition to any defined user location whether connected to a local network or remote via cellular modem, or wide-area network.
    1. Alarm generation shall be selectable for annunciation type and acknowledgement requirements including but not limited to:
      1. Alarm
      2. Return to normal.
      3. To default.
    2. Alarms shall be annunciated in any of the following manners as defined by the user:
      1. Screen message text.
      2. Email of complete alarm message to multiple recipients.
      3. Pagers via paging services that initiate a page on receipt of email message.
      4. Graphics with flashing alarm object(s).
    3. The following shall be recorded by the PPCU for each alarm (at a minimum):
      1. Time and date.
      2. Equipment (air handler #, access way, etc.).
      3. Acknowledge time, date, and user who issued acknowledgement.
  14. PPCU Controllers shall support at minimum the following control techniques:
    • General-purpose control loops that can incorporate Demand Limit Control strategies, Set point reset, adaptive intelligent recovery, and time of day bypass.
    • General-purpose, non-linear control loops.
    • Start/stop Loops.
    • If/Then/Else logic loops.
    • Math Function loops (MIN, MAX, AVG, SUM, SUB, SQRT, MUL, DIV, ENTHALPY).
  15. The following twenty-six [26] integral Inputs/Outputs shall be supported per each PPCU:
      1. Six integral 12 Bit resolution Universal Inputs (configurable as 20K NTC, 10K NTC, 0/2-10V, 0/4-20mA, 0.4Hz Dry Contact).
      2. Four integral dry contact / totalizer Digital Inputs. Totalizer: 15Hz (25ms on, 25ms off, 5ms bounce).
      3. Four integral 8 Bit 0-10 Vdc Analog Outputs with configurable safety position selections.
      4. Eight integral Digital Outputs.
        1. Four Relay normally open contact at 3A, 250Vac, 30Vdc.
        2. One Relay normally open contact at 10A, 250Vac, 30Vdc with configurable safety position selections.
        3. Three Relay normally open contact with common feed at 3A, 250Vac, 30Vdc with configurable safety position selections.
      5. The PPCU shall employ a device count capacity license model that supports I/O expansion capabilities.
  16. Each PPCU shall have expansion ability to support additional I/O requirements through the use of remote input/output modules and a local communication bus. Each PPCU shall be able to support a maximum of 1,200 physical I/O points.
    1. I/O-specific modules (UI, BI, AO, BO) shall require a Terminal Socket Module that includes screw or push-in terminals for field device wires, communication, and port to accept pluggable I/O-specific Module. I/O-specific Modules shall be hot pluggable and shall be replaceable without rewiring.
    2. Remote Universal Input Module (8 UI).
      • Eight Universal Inputs; 0/2-10V, 0/4-20mA, 20K NTC, 10K NTC, PT1000-1, PT1000-2, NI1000TK5000, PT3000, BALCO500, Binary Input (0 / 10V with pull-up).
    3. Remote Binary Input Module (12 BI).
      • Twelve Binary Inputs; Dry contact or Totalizer (20Hz)
      • Each Binary Input shall include a configurable status LED (Alarm: red/green; Status: yellow/off).
    4. Remote Analog Output Module (8 AO).
      • Eight Analog Outputs with configurable safety position selections. 8 Bit Analog Outputs; 0-10V, Floating Actuator, Binary Output (0V / 10V).
      • Each Analog Output shall include a RED status LED that varies brightness based on signal level & flashes in override mode (with manual override Module).
      • Optional version with manual override potentiometer per output.
    5. Remote Relay Output Module (6 BO).
      • Six Relay Outputs with configurable safety position selections.
      • Each Relay Output shall include a yellow status LED.
      • Optional version with manual override switch per output (Auto, 0, 1).
    6. Remote Floating Output Module (3 FO).
      • Three Floating Outputs with configurable safety position selections. 2 Relays per Floating Output.
      • Each Floating Output shall include a RED status LED (opening) and a GREEN status LED (closing).
      • Manual override potentiometer per output.
    7. Remote Mixed I/O Module (8 UI, 12 BI, 8 AO, 6 BO)
      • Eight Universal Inputs; 0/2-10V, 20K NTC, Binary Input (dry contact).
      • Twelve Binary Inputs; Dry contact or Totalizer (15Hz)
        • Each Binary Input shall include a yellow status LED.
      • Eight Analog Outputs with configurable safety position selections. 10 Bit Analog Outputs; 0-10V, Binary Output (0V / 10V).
      • Six Relay Outputs.
        • Each Relay Output shall include a yellow status LED.
  17. The PPCU shall be provided with <or without> an integrated Local Operator Interface.
    1. Local Operator Interface shall allow for User-ID and password protected access.
    2. Local Operator Interface shall provide a backlit display, with automatic backlight time-out.
      • The display backlight shall automatically light upon press of a key or operation of the push & turn wheel. The display backlight will extinguish if operating keys or push & turn wheel is not used for two minutes.
    3. Local Operator Interface shall provide full display of long text information.
      • Automatic left and right scrolling shall ensure that text information longer than the display width can be viewed.
    4. Local Operator Interface shall provide configurable screens for viewing and adjusting data points and parameters, including the following operations.
      • Automatics and visual notification of all critical alarms.
      • Read and write access to all data points.
      • Full length names of data points, schedules, calendars, parameters, alarm texts, state texts and alarms.
      • Read and write access to all application parameters.
      • Read and write access to all schedules and calendars.
      • Read access to the onboard alarm buffer.
      • Overview of all data points in manual override.
      • Overview of all data points in alarm.
    5. Local Operator Interface shall allow user access to text information via a push & turn operation wheel.
      • Scrolling through a list of information shall be accomplished by turning the operation wheel.
      • Selecting and acknowledging information shall be accomplished by pushing the operation wheel.
    6. Changing information shall be accomplished by turning the operation wheel.

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