Agilent CareNet Controller Service manual
Installation and Service Guide
Agilent Serial Distribution Network (SDN)
78581B Agilent CareNet Controller (ACC)
Part Number 78581-92000
Printed in the U.S.A. February 1, 2001
First Edition
Notice
Proprietary
Information
Warranty
This document contains proprietary information that is protected by
copyright. All Rights Reserved. Reproduction, adaptation, or translation
without prior written permission is prohibited, except as allowed under the
copyright laws.
Agilent Technologies, Inc.
3000 Minuteman Road
Andover, MA 01810-1099
(978) 687-1501
Publication number
78581-92000
Printed in USA
The information contained in this document is subject to change without
notice.
Agilent Technologies makes no warranty of any kind with regard to this
material, including, but not limited to, the implied warranties or
merchantability and fitness for a particular purpose.
Agilent Technologies shall not be liable for errors contained herein or for
incidental or consequential damages in connection with the furnishing,
performance, or use of this material.
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New editions of this document will incorporate all material updated since
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date to change). The document part number changes when extensive
technical changes are incorporated.
First Edition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . February 2001
Copyright © Agilent Technologies, Inc. 2001
Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
SDN System Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
SDN Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
SDN Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
Operating Reliability — Failure/Restart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
SDN Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Agilent CareNet Controller (ACC), Model 78581B . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
ACC Controls and Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
ACC Servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Cables, Wall Boxes, and Faceplates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Branch Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Local Distribution Cables (LDC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Wall Boxes and Face Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-6
SDN Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
78599AI SDN Cabling Installation Kits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-7
M3199AI Installation Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
M3180A Wall Mount Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
Intended Use of Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
2. Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-1
SDN Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-2
SDN General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-2
Logic Convention. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-3
SDN Topology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Applications of SDN Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Instrument Communication on the SDN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
SDN Timing Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Autopoll Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
SDN Data Structure — System and Instrument Messages . . . . . . . . . . . . . . . . . . . . . 2-9
System Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Instrument Messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
SDN Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
SDN Data Timing Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
Instrument Status Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
SDN/Autopoll . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-12
ONLINE/OFFLINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12
NETWORK/LOCAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12
SDN Status and Error Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12
ACC Error Conditions — SDN Failure Detection . . . . . . . . . . . . . . . . . . . . . . . . 2-13
ACC Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14
Main PCB (78581-60200) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14
Transition Board (78581-61253) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15
Power Supply (M2604-60002) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15
Contents-1
3. SDN and ACC System Level Troubleshooting . . . . . . . . . . . . . . . . . 3-1
SDN Troubleshooting Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Troubleshooting Resources, Tools, and Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
SDN Troubleshooting Flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
STEP #1: Review Customer’s System Configuration . . . . . . . . . . . . . . . . . . . . . . 3-5
STEP #2: Examine System and Gather Symptoms . . . . . . . . . . . . . . . . . . . . . . . 3-5
SDN Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
SDN Error Messages and Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
Diagnose the Problem as SDN or Non-SDN . . . . . . . . . . . . . . . . . . . . . . . . . .3-6
Noisy Branch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-6
SDN and Non-SDN Related Problems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
Action. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-7
STEP #3: Evaluate the Breadth of the Problem . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
Action. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-8
STEP #4: Self-Test Check of SDN Interface Circuitry . . . . . . . . . . . . . . . . . . . . . 3-8
STEP #5: Isolating a Problem on A Local Distribution Network (LDN)
With Two or More Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
Miscellaneous Items . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-12
Recap of Troubleshooting Procedures: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-12
Reverification Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13
Cable Verification Procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13
Hardware Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
Verify Instrument End of the Branch Cable . . . . . . . . . . . . . . . . . . . . . . . . 3-14
Verify Proper Operation of Priority Wires . . . . . . . . . . . . . . . . . . . . . . . . . .3-15
SDN Bedside:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15
Ground Check Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16
4. ACC Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
ACC Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
ACC Failure, Power Up, and Power Down Procedures. . . . . . . . . . . . . . . . . . . . 4-1
5. Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Part Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
6. Component Installation and Disassembly Procedures . . . . . . . . . . 6-1
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-1
Typical SDN System Interconnecting Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-1
Installation Responsibilities—Customer and Agilent Technologies . . . . . . . . . . . . . 6-3
Customer Installation Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
Agilent Installation Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
7. Site Preparation/Installation Checklists . . . . . . . . . . . . . . . . . . . . . 7-1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-1
Verification Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8
Overview of SDN/ACC Installation and System
Communication Verification Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8
Planning and Configuration Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-8
Standalone Instrument Verification and Installation . . . . . . . . . . . . . . . . . . . . . 7-8
Contents-2
8. Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1
SDN Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1
SDN Wiring Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1
Instrument Connection to the SDN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1
System Communication Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1
Practical Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1
Test and Inspection Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2
When to Perform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4
Installation Tools, Materials, and Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4
SDN Installation Restrictions and Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4
ACC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5
Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5
Wall Boxes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
ACC Mounting Location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
Rack Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
Service Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
AC Power Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
Environmental Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7
Important Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7
ACC Wall Mounting Procedures and Power Installation . . . . . . . . . . . . . . . . . . . . . 8-8
Plywood Panel Mounting Procedures — Customer’s Responsibility . . . . . . . . . 8-8
ACC Wall Mounting Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8
Install Cable Enclosures, Wall Boxes, and Branch Cables . . . . . . . . . . . . . . . . . . . . 8-9
Install Branch Cable Enclosures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9
Selecting Conduit Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9
Formula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10
Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10
Install Standard NEMA Switch Wall Boxes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-11
Install Branch Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-11
SDC Standard System Distribution Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-12
XSDC Extended System Distribution Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-12
Unshielded Twisted Pair Distribution Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-12
SDC and XSDC Wall Box Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-12
SDN on UTP Wall Boxes Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-15
UTP Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-15
Parts Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-16
Equipment Needed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-16
Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-18
ACC Procedures (78581B). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-18
Perform Final Operational Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-18
Serial Communication Controller (SCC) Procedures (78581A) . . . . . . . . . . . 8-19
Terminate UTP Cable at Patch Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-19
Terminate UTP Cable at Wall Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-20
Qualify UTP Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-21
Install Local Distribution Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-23
Connect LDC from Wall Box to Instrument(s) . . . . . . . . . . . . . . . . . . . . . . . . . 8-24
Terminate Variable Length LDC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-25
Terminate SDC and XSDC Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-26
Contents-3
9. SDN/ACC System Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1
Compliance with IEC 60601-1-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1
Device Grounding on the SDN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-2
10. SDN/ACC Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1
SDN Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-1
ACC Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-3
Cleaning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-4
System Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-4
Contacts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-5
Contents-4
SDN System Description
The Serial Distribution Network (SDN) is a local area communications
network designed to share patient physiological parameters and other
data among bedside instruments, information centers (IC), recorders,
thermal printers, computer systems, and other information systems
connected to the system. The SDN is a digital communications network
that allows real-time transfer of digitized patient data between these
instruments. The communication protocol, data formatting, and hardware
implementation is intended to be flexible enough to accommodate a
variety of communication needs in the patient monitoring environment for
present and future expansion.
Introduction
Section 1: Introduction
SDN
Components
SDN Operation
The components of the SDN consist of the model 78581B Agilent CareNet
Controller (ACC), the SDN interface circuitry located within each
instrument connected to the SDN, and the system distribution cables
(branch cables), local distribution cables, and the associated wallbox
hardware, connectors and receptacles. The components of the SDN are
shown on page 1-2, and a typical SDN configuration is illustrated in Figure
1-2 on page 1-3.
The SDN functions automatically without user interaction and without
direct patient connections. Digitized patient information from each
instrument (branch) is transmitted serially at regular intervals (called poll
cycles) over branch cables to the ACC. The ACC sequentially receives,
synchronizes, and rebroadcasts the digitized patient information to all
instruments connected to the SDN. This patient data is received for use by
each instrument via the SDN interface circuity resident in each
instrument. Patient data are not restricted or allocated by the network,
but are accepted from, and transmitted to, all instruments within the
system. Each instrument decides for itself which patient information it
wants to acquire and process. Each instrument gets a chance to transmit
and receive patient information every poll cycle. A poll cycle lasts 32 ms,
thus, there are approximately 32 poll cycles per second.
Digitized patient information transmitted over the SDN may be either
waveforms (for ECG, pressure, and respiration) or parametric information
(for heart rate/pulse, pressure valves, and respiration rate). The SDN data
transmission rate of 3.6 Mbits can provide up to 7700 usable 12-bit data
1-1
SDN System Description
words per 32-millisecond poll cycle. The SDN is a half-duplex network
using terminated shielded twisted pair cable(s). All data is transmitted
differentially and serially using block code modulation. A detailed
description of the SDN system theory of operation is given in a subsequent
section of this manual.
Within the connected instruments, SDN interface circuitry provides the
link between the serial digital network, and the instrument connected to
the SDN (except the ACC) has basically the same interface circuitry, most
of which is contained on a custom integrated circuit called the SDN
Interface Circuit Chip (SIC Chip). A detailed description of the SIC Chip
theory of operation is given in a subsequent section of this manual.
1-2
Figure 1-1. SDN Components
Introduction
CCU/PCU ER
AIC
8
Bedsides
4 Telepaks
015
16 31
Tele
Mainframe
Figure 1-2. Typical SDN Configuration
Operating Reliability — Failure/Restart
Power Failure: ACC operation resumes automatically after power
restoration. Loss of power to the ACC will not affect local operation
between instruments on a branch that do have power. Loss of power at
one instrument on a branch will not disrupt system communication of
other instruments on the same branch or any other branch of the network.
ACC
AIC
4 Bedsides
AIC
4 Bedsides
4 Telepaks
SDN Configurations
Various combinations of patient monitors and patient information centers
may be connected to the ACC providing the system is configured within
the certain restrictions and limitations.
The ACC can accommodate up to 32 separate branch cables emanating
from it to the wall boxes (instruments). Of the 32 total branches, 24 may
connect to HP and Agilent bedside instruments (one patient per branch—
see note below), 6 may connect to information centers, and 2 may connect
to computerized systems. Refer to the installation section of this manual
for a complete listing of SDN System, ACC, cables, and wall boxes
restrictions and limitations.
1-3
Agilent CareNet Controller (ACC), Model 78581B
Agilent CareNet Controller (ACC), Model 78581B
The Agilent CareNet Controller (ACC), model 78581B, is the active node—
in essence the heart—of the Serial Distribution Network (SDN). The
primary functions of the ACC are to provide the physical system
communications link to the instruments connected to the SDN, to establish
the SDN data polling cycles, and to control the data flow, timing,
synchronization, and distribution throughout the system.
The ACC functions in conjunction with the SDN Interface Circuitry located
within each instrument connected to the SDN, and with the system
distribution cables (branch cables), local distribution cables, and the
associated wallbox hardware, connectors and receptacles. A typical SDN
system configuration is illustrated in Figure 1-2 on page 1-3.
Once each poll cycle, data from each instrument is transmitted over the
branch cables to the ACC. All this data are received in sequence,
synchronized, and controlled by the ACC, then transmitted (broadcast)
simultaneously to all of the instruments connected to the SDN during each
32-millisecond poll cycle. The data sent over the SDN bus is received for
use by each instrument via the SDN interface circuitry residing in each
instrument. The ACC cannot store, restrict, or allocate specific
distribution of SDN data.
The ACC controls the data communication sequence during the 32millisecond poll cycle by issuing a variety of system messages that
originate in the ACC. A complete description of system messages,
instrument messages, the SDN data communicating sequence and SDN bus
direction control is described in the SDN system theory of operation
section of this manual.
Additionally, the ACC performs some basic fault detection isolation to
ensure reliability of SDN system communications. Also included in the
ACC are resident self-diagnostic routines for fault detection,
troubleshooting, and servicing of the ACC.
The ACC consists of a metal chassis with cover, a Power Supply Assembly,
a Terminal Interconnect PC board, and a Control/Driver PC board. The
model 78581B Agilent CareNet Controller is illustrated on in Figure 1-3 on
page 1-5.
The Control/Driver PC board contains all the electronic circuitry required
to control the data flow, timing, and distribution of SDN data throughout
the system.
The Terminal Interconnect PC board contains the RJ-45 connection to
connect the branch cables to the ACC, and the signal feed-through ribbon
cables to the Control/Driver PC board.
The Power Supply assembly contains the power ON/OFF indicator, and a
5-volt linear DC voltage supply used to power the circuitry on the Control/
1-4
Introduction
Driver PC board. This model of the ACC does not have a power ON/OFF
switch. Power comes on as soon as it’s connected to AC by power cord. To
disconnect the power, remove the plug from the wall receptacle.
ACC Controls and Indicators
There are no operator controls located on the ACC. Once the power cord is
connected and the ACC is running properly, no operator adjustments are
necessary.
The green power ON/OFF indicator is visible on the rear. When
illuminated, it indicates 5-volt power is available from the ACC power
supply.
ACC Servicing
The ACC has been designed for ease of servicing. PC board and assembly
replacement is the primary method of repair. Troubleshooting tests and
integrity routines are specified in detail the ACC Troubleshooting section
of this manual. Complete disassembly procedures of the ACC are
described in the Installation section of this manual.
Figure 1-3. Agilent 78581B Agilent CareNet Controller
1-5
Cables, Wall Boxes, and Faceplates
Cables, Wall Boxes, and Faceplates
Branch Cables
There are three types of branch cables that are permanently installed to
provide long distance connection between the ACC and the wall box; the
standard System Distribution Cable (SDC), the Extended System
Distribution Cable (XSDC), and Category 5 Unshielded Twisted Pair
(UTP).
The length of Unshielded Twisted Pair runs must be less than 90 meters
(295 ft.). The length of each standard SDC must be less than 152 meters
(500 ft.). The length of each XSDC must be less than 304 meters (1000 ft.).
Only two XSDC runs are allowable per ACC. Branch cable runs must be
continuous; no splicing or mixing cable types is allowed.
Local Distribution Cables (LDC)
The SDN allows ease and flexibility of user placement of instruments.
Local distribution cables (LDC) must be used for local serial connection
from the wall box/face plate to the instrument, and to other instruments.
The LDC allows bedside instruments to be easily interchanged simply by
connecting them to their new locations.
Wall Boxes and Face Plates
Wall Boxes: only standard size, NEMA, single- or dual-gang, switch wall
boxes with conduit knockouts (KOs) may be used. The depth of the wall
box must be at least 7.0 cm (2.75 in). Wall boxes are usually supplied by
the customer; however, two types are available from Agilent Technologies.
Face Plates: Pre-punched, NEMA, single- or dual-gang faceplates for the
SDN; SDN on UTP US and European wall boxes. Faceplates are included
with the wall box connector kits.
1-6
SDN Components
Introduction
Installation of a complete Serial Distribution Network requires the
ordering and selection of several instruments, SDN system components
and options. These include the model 78581B ACC and options from the
78599AI/Cabling Installation Kit to provide Local Distribution Cables
(LDC) and connector hardware. Branch cables are ordered separately
using their associated Agilent part number.
Refer to the Installation section of this manual for a complete description
of the installation instructions and responsibilities for properly installing
the ACC, the cables, and the wall boxes. The general SDN instrument
interconnection procedures are also given in the installation section;
however, the specific details of instrument wiring procedures and ‘tuning”
the instruments into the SDN communications network are explained in
detail in the associated instrument’s service manual.
The ACC may be mounted on a standard 19 inch telecommunications rack.
It may also be wall mounted on a properly prepared wall, using the wall
mount kit (M3180AI),
within the specified length limitations. No special tools are required for
installation—only screw drivers, cable strippers, and pliers are needed.
Environmental conditions, service access requirements, and free space
surrounding the ACC are detailed in the Installation section of this
manual.
that permits the length of each branch cable to be
System Distribution Cable (SDC) 100-ft. reel
Extended System
Distribution Cables (XSDC)
UTP Category 5 Orange 1000-ft. reel 8120-6770
78599AI SDN Cabling Installation Kits
— J01 Single Gang SDN Face Plate/Connector Kit
— J02 Dual Gang SDN Face Plate/Connector Kit
— J12 SDN/UTP Single Wall Box Quantity 1
— J13 SDP/UTP Single Wall Box Quantity 8
— J14 SDN/UTP Dual Wall Box Quantity 1
— J15 SDN/UTP Dual Wall Box Quantity 8
Table 1-1: SDN Branch Cables
250-ft. reel
500-ft. reel
750-ft. reel
1000-ft. reel
8120-3502
8120-3775
8120-3774
8120-3777
8120-3776
1-7
Intended Use of Device
— JJ1 SDN on UTP parts (European) Quantity 1
— JJ2 SDN on UTP parts (European) Quantity 8
— J03 3-Foot Local Distribution Cable (LDC)(81 20-3591)
— J06 6-Foot Local Distribution Cable (LDC)(81 20-3587)
— J10 10-Foot Local Distribution Cable (LDC)(8120-3588)
— J20 20-Foot Local Distribution Cable (LDC)(8120-3589)
— J50 50-Foot Variable Length LDC Kit
— J52 Extra SDN Connectors (Two)
— J54 Fifty Feet of Unterminated LDC
M3199AI Installation Materials
— P01 UTP Plenum (Orange) Cat. 5 Cable 1000 Feet
M3180A Wall Mount Kit
Intended Use of Device
The Signal Distribution Network (SDN) allows the sharing of patient
physiological parameters and other electronic data among bedside
instruments, central station processors and displays, recorders, thermal
printers, and other computerized systems.
Warning
United States Federal Law restricts this device to sale by or on the
order of a physician.
This product is not suitable for installation in the patient care
vicinity.
— J03 RJ45 to SDN Cable Connector
— A14 Wall Mount Kit (78581-61257)
1-8
Overview
Theory of Operation
Section 2: Theory of
Operation
Theory of operation consists of two distinct subsections:
• SDN Theory of Operation
• ACC Theory of Operation
SDN Theory of Operation describes the overall system Serial Distribution
Network (SDN), its normal operating characteristics, applications, and
error conditions, the format of the SDN digital data, and the SDN system
communications protocol as well as the local distribution network (LDN)
communications protocol. The SDN system communication protocol and
data formatting assures compatibility between a variety of different
instruments communicating together over the SDN. The communication
protocol and hardware implementation is intended to be flexible enough
to accommodate a variety of communication needs in the patient
monitoring environment for the present and for future expansion.
ACC Theory of Operation describes the detailed operating theory of the
Agilent CareNet Controller (ACC). Included in this section are functional
descriptions of the Power Supply Assembly, the Terminal Interconnect PC
board, and the detailed operating principles of the Control/Driver PC
board which includes the transmit/receive driver circuitry, the retiming
circuitry, and the control circuitry.
2-1
SDN Theory of Operation
SDN Theory of Operation
SDN General Description
The Serial Distribution Network (SDN) is a digital communications
network designed to share patient physiological parameters and other
data among all instruments connected directly to the SDN.
The SDN uses cables containing a twisted shielded pair of wires to connect
the instruments to the Agilent CareNet Controller (ACC). Digitized patient
data is transmitted SERIALLY through the wires of the NETWORK. The
ACC circuitry manages the timing and DISTRIBUTION of the digital
patient data. Hence, it is appropriately named the SERIAL DISTRIBUTION
NETWORK.
The SDN is a half-duplex network using terminated shielded twisted pair
cable(s) to carry serial digital data. All SDN data is transmitted
differentially and serially using block code modulation. Brief explanations
of the SDN terms are given below.
Term Definition
SDN Data Physiological information such as parameters or
waveforms, or non-physiological information such
as bed labels, annotation, alarm messages, or timeof-day.
Digital Using binary logic where a high voltage level is
called a one (1) and a low voltage level is called a
zero (0).
Serial A string of ones (1) and zeros (0) in a row create
defined words, similar to alphabetic letters used to
define known words. However, the SDN words are
all the same length. These words are combined to
make up messages. Different messages have
different lengths.
Half-Duplex Signals move in one direction at a time over the
data wires. Instruments using the SDN never talk
and listen at the same time.
Block Coded A digital coding scheme that facilitates sending
serial digital data by insuring not too many ones (1)
or zeros (0) are transmitted. Timing information is
extracted from the frequent edge transitions (0 to 1,
or 1 to 0). This keeps all instruments synchronized
while minimizing the bandwidth required.
2-2
Theory of Operation
Term Definition
Shielded Twisted Pair
Custom Cable
LAN Unshielded Twisted
Pair Category 5
Differential Two wires carry the same signal, with opposite
Termination In order for differential signals to remain clean, the
A cable containing two wires which carry all digital
data on the SDN. The two wires are twisted together
to minimize interference from magnetic fields, and
encased in a braided shield to limit interference
from electrostatic fields. The cable is custom
designed with carefully controlled impedance and is
well shielded to guarantee noise immunity and
ensure system performance. It is necessary to use
only Agilent supplied cables in SDN systems.
A cable containing four pairs of wires. One pair
carries all digital data on the SDN. The wires are
twisted together to minimize interference from
magnetic fields. UTP, unlike shielded twisted pair, is
not encased in a braided shield.
polarity. These two wires are designated as positive
and negative. For a digital one (1), the positive wire
is at a high voltage and the negative wire is at a low
voltage; vice versa for a digital zero (0). The voltage
between these wires (high to low, 1 to 0) is
approximately 3 volts (1.5V minimum, 4V
maximum).
length of the cable must appear infinite to the
circuitry. The cable’s impedance is matched by 120
ohms of resistance connected between the two data
wires at both ends of the branch (at the ACC and at
the instrument). Termination is contained in each
instrument.
Logic Convention
Data Wires (SDC or XSDC)
Positive (+) Wire Pink colored wire
Negative (–) Wire Blue colored wire
High State (1) (True) Pink wire potential is positive with respect to blue wire
Low State (0) (False) Pink wire potential is negative with respect to blue wire
Positive Transition Transition from low state to high state
Negative Transition Transition from high state to low state
by at least 1.5V
by at least 1.5V
2-3
SDN Theory of Operation
SDN Quiescent State Pink wire biased O.4V more negatively than blue wire.
Data Wires (LDC only)
Positive (+) Wire Pink colored wire
Negative (–) Wire Blue colored wire
Priority Wires (LDC only)
Positive (+) Wire Gray colored wire
Negative (–) Wire Black colored wire
True State Black wire positive with respect to gray wire
False State Black wire negative with respect to gray wire
UTP
Positive (+) Wire Blue wire with white stripe
Data wires are quiescent during dead time.
Negative (–) Wire White wire with blue stripe
Ground Green wire
2-4
SDN Topology
Theory of Operation
The SDN uses a star topology that consists of up to 32 individual branches
emanating from the center of the star—the ACC. Only one ACC may be
used per SDN. One SDN can accommodate up to 24 bedside instruments
(one patient per branch), 6 information centers (ICs), and 2 computerized
monitoring systems. For details on specific operational and topological
limitations, refer to the Installation section.
A typical SDN configuration is illustrated below.
Figure 2-1. Typical SDN Configuration
2-5
Applications of SDN Operation
Applications of SDN Operation
Configurations of the SDN will vary from installation to installation. The
SDN is designed to be flexible enough to accommodate a variety of
communication needs in the patient monitoring environment, for the
present and for future expansion. Many hospitals have more than one care
unit. For example, there might be separate care units such as an ICU, a
CCU, an MICU, and an SICU. SDN communication between instruments
can be customized at installation.
One of the applications on the SDN is the OVERVIEW display. This feature
provides a split display screen showing “home bed” and “source bed”
patient information. This OVERVIEW mode can be entered either
manually for observation or automatically upon patient alarm. Any bed/
patient within the same care unit can be displayed in this manner.
Softkeys on the monitor are used to form subgroups under the care of
each nurse, called care groups, to match nursing assignments. The features
of split display screens, message transfer, alarm alert, and care group
configuration are all possible using the digital Serial Distribution Network.
In addition, any defined message can be transmitted via serial digital data
without requiring any changes to network hardware. There are 63
physiological function codes of which 42 are defined and 21 are reserved
for future use. The SDN is flexible enough to accommodate configuration
changes at the bedside instrument via plug-in modules without any system
modifications, user interaction, or hardware changes. Also, SDN
instruments may be disconnected at any time and moved to other system
locations and reconnected without bringing the network down.
Another application on the SDN is the TUNING feature at an Information
Center. This feature provides the ability to choose which patients/beds are
monitored at the IC. Patient information viewed at the IC is displayed in
dedicated positions on the display screen called SECTORS.
The sectors may be individually TUNED to any bedside instrument using
the softkeys. Any number of ICs may tune to the same patient/bed. The
first IC to be tuned to a bedside is called the “primary” IC for that bedside
instrument, and furnishes recordings when requested from that bedside.
Sectors on other ICs displaying the same bedside information are called
“consulting sectors.” All sectors tuned to a given bedside report patient
alarms.
Instrument Communication on the SDN
The ACC is the active node of the SDN. It functions to provide the system
communications link and to control the data flow, timing, synchronization,
and distribution throughout the system. The ACC functions in conjunction
with the SDN interface circuitry located within each instrument connected
to the SDN. The SDN interface circuitry drives and receives SDN data over
2-6
SDN Timing Overview
Theory of Operation
the branch cables for instrument-to-system communication via the ACC,
and also over the local distribution cable(s) for instrument-to-instrument
communication when the local distribution network (LDN) exists.
Only one instrument broadcasts patient data at a time and the ACC
rebroadcasts that information from that branch to all other branches on
the system. The ACC functions as a rotary switch successively allowing
each branch to transmit data to all other branches. The communication
system is designed so every instrument gets a chance to transmit all its
available data within predetermined cycles. The functional operation and
timing sequence of the SDN communication cycle is described below.
Most information is broadcast by the SDN instruments once every system
cycle, or approximately once every second, such as bed labels, derived
parameters and time-of- day. Other system information, such as
physiological waveform data, is broadcast once every poll cycle or 32
times a second. The ACC controls data communication on the SDN in
blocks of time called system cycles. One system cycle lasts 1.024 seconds
and is made up of 32 separate poll cycles.
Poll Cycle: One poll cycle lasts 32 milliseconds. Each poll cycle is made up
of three distinct segments, which are:
SYNC TAP 4 MS DEAD TIME TALK TIME
Sync Tap. The sync tap acts as a system synchronization strobe. It is sent
by the ACC to all branches (instruments) simultaneously to synchronize
the instrument’s transceivers and to initiate the beginning of a new poll
cycle. The sync tap also contains coded status information.
4 Ms Dead Time. The 4 ms dead time is an enforced quiet time that
immediately follows the sync tap.
During the 4 ms dead time each instrument reads data stored by the SDN
interface circuitry during the previous poll cycle and stores data to be sent
during this poll cycle. This is the only time SDN data can be loaded into
and retrieved from the instrument’s SDN interface circuitry.
Talk Time. During the talk time a talk tap message is sent to one branch at
a time starting with branch 0 to grant permission to talk on the SDN.
When a talk tap has been received, the instrument on that branch
transmits all of the data stored in its transmit memory. When finished, the
ACC senses silence on the branch and sends a talk tap to the next branch.
The amount of data transmitted during the talk time varies from branch to
branch and changes from poll cycle to poll cycle, so talk taps do not occur
in the same place every cycle. After all branches have been polled once, no
more data is transferred until the next poll cycle.
2-7
SDN Data Structure — System and Instrument Messages
Autopoll Mode
In the event that the ACC goes down (loses power, for example), all
instruments on the same branch continue to communicate with each other
in the autopoll mode. Autopoll means that the first instrument (closest to
the wall box) sends sync taps and talk taps to itself and the other
instruments on the branch. The timing is exactly the same as normal SDN
operation. When the ACC resumes proper operation, the instrument
automatically leaves the autopoll mode and returns to SDN
communication.
SDN Data Structure — System and Instrument Messages
Digitized information travels serially on the SDN in 12-bit words. These
words are grouped together in a string to form complete messages. The
SDN uses two types of messages: system messages which originate in the
ACC or in the first instrument on branch when in the autopoll mode and
instrument messages that originate in the instruments.
System Messages
System messages originate in the ACC. System messages consist of three
separate 12-bit words and have the following structure:
FLUSH
Flush: The flush is a unique sequence of 12 bits (101010101010) that are
used to clear the line of capacitive charging to ensure reliable detection of
logic levels. The flush word always follows any silence on the SDN bus.
System Delimiter: The system delimiter is another unique sequence of 12
bits (100000111111) that are used to help the instruments’ transceivers
recognize the system message and establish synchronization.
System Status Word: The system status word consists of either a sync tap
or a talk tap.
Sync Tap: The sync tap carries encoded information to indicate whether
the current poll cycle is the first poll cycle in the system cycle (master poll
cycle), to flag “fire axe” and “poll overflow” error conditions (see “SDN
Status and Error Conditions” on page 2-12), and to identify the “autopoll”
operating mode (see “Autopoll Mode” on page 2-8).
SYSTEM
DELIMITER
SYSTEM STATUS
WORD
2-8
Theory of Operation
Talk Tap: The talk tap carries encoded information to indicate the branch
number and to identify the “autopoll” operating mode.
Note
Instrument Messages
INSTRUMENT
DELIMITER
Since the status information is block encoded, there is not a one-to-one
correspondence between status values and bits of the status words. The
condition of these bits are indicated on the status LEDs on the ACC and on
the display screens of the SDN instruments. See “SDN Status and Error
Conditions” on page 2-12.
Instrument messages originate in the instrument. These instrument
messages comprise of all the data broadcast on the SDN, such as
waveforms, derived parameters, alarm status, text messages, bed labels,
time-of-day, and many others. Instrument messages vary in length (i.e.,
number of words) but always consist of the following structure.
HEADER
HEADER
Instrument Delimiter: The instrument delimiter is a unique 12-bit word
(110010011111) used to mark the beginning and the end of the message.
Header: The header is always four words long (48 bits) and is used to
label the content of the message body. The second word is called the
“signature.” Listening instruments examine the signature to determine
whether they want to capture this message.
BODY
INSTRUMENT
DELIMETER
Body: The body of the instrument message contains the actual data. The
number of data words in the body depends upon the type of message being
sent.
2-9
SDN Normal Operation
SDN Norma l Operation
This section contains the SDN data timing specifications and a description
of the instrument status message.
SDN Data Timing Specifications
During normal operation SDN digital data travels on the SDN at 3.6 Mbit;
the bit cell width is 1/3,600,000 seconds, or 277.78 ns.
10101
277.78ns
Bit Cell Width
Therefore, the 12-bit word is 3.33 µs long. One poll cycle lasts 32 ms, but
not all of this time is available to transmit data. Considering all of the
overhead time (see breakdown below), approximately 7700 words of data
can be transmitted in every poll cycle. Overhead time consists of the
following:
a. Sync tap (10µs)
b. Dead time (4 ms)
c. Time to listen for activity on each branch before sending a talk tap
(3.33 µs per branch)
d. Talk taps (10µs per branch)
e. Time to listen for silence before going on to the next branch (12.22 µs
per branch)
f. Headers and delimiters in messages
Instrument Status Me ssage
Once every system cycle (approximately once a second) each instrument
connected to the SDN broadcasts a message called the Instrument Status
Message. The content of this message allows all other instruments to
identify its operational status. Contained in every Instrument Status
Message are the following:
2-10
Theory of Operation
a. Instrument Identification: Each instrument can be identified as any
SDN bedside monitor, IC, or computer. For bedsides the instrument
identification gives branch number and type of bedside monitor.
b. SDN Communication Error Flags: A variety of SDN system errors are
identified and flagged in the instrument status message. Refer to the
Troubleshooting section for details on the network test and SDN
system troubleshooting.
c. Status Indicators: Three unique status indicators reflect the
instrument’s ability to communicate on the SDN. The three status
indicator bits in the instrument status message are described below.
Each bit can have a value of 0 or 1. In normal operation the status
indicator bits are set to 1.
SDN/Autopoll
ONLINE/OFFLINE
NETWORK/LOCAL
The normal operating mode is SDN. The ACC’s sync tap indicates to the
instruments that they are in the SDN mode. If operation of the ACC fails
(loses power for example), then one instrument on each branch generates
its own sync taps and talk taps that it sends to itself and to the other
instruments on that branch. Thus, the local communication is maintained.
The locally generated sync tap indicates to the instruments on that branch
that the branch is operating in Autopoll mode.
If the ACC becomes active again, then the branch automatically returns to
the SDN mode.
The normal operating mode is ONLINE. The ONLINE status indicates that
an instrument has examined itself and is ready and able to operate
reliably on the SDN. At power up an instrument is OFFLINE. When it
successfully completes its own initialization it may put itself in the
ONLINE state.
The normal operating mode is NETWORK. The NETWORK status indicates
that an instrument is synchronized with the system cycle. This is
important because most of the data on the SDN is sent only once each
system cycle, during a specific poll cycle. An instrument must synchronize
with the master poll cycle in order to know when to transmit specific data.
At power up an instrument is in LOCAL mode and starts searching for the
beginning of a system cycle. As soon as a valid system cycle has been
found, the instrument may set itself in NETWORK mode.
SDN Status and Error Conditions
SDN system status and error conditions can be viewed on the IC display,
bedside, and indicated on the ACC via LED status and error code
indicators. A detailed description of the SDN system errors is described in
the SDN troubleshooting section.
2-11
SDN Normal Operation
ACC Error Conditions — SDN Failure Detection
The functional operation of the ACC can be checked and verified to ensure
reliable operation. During normal operation, the following LEDs on the
Control/Driver PC board are illuminated continuously:
RED DS1 (MSB) flickers
RED DS4 (LSB)
GREEN DS5 (RUN)
RED DS6 (Ti)
DS6
DS5
2-12
DS1 DS2 DS4DS3 DS8 DS7
The ACC is designed to detect and isolate certain fault conditions which
may be present on the SDN bus.
Fire Axe: One type of fault condition that could occur is the presence of
activity on a branch which has not yet been sent a talk tap. The ACC
senses the branch for 3.3 µs before sending a talk tap message. If activity
is detected during this time, then no talk tap is sent and the ACC skips
over that branch automatically and cuts it off from the rest of the SDN.
This condition is called “fire axe”, and is indicated at the ACC by
illuminating the yellow fire axe LED DS8. However, if no activity is
detected on a branch, the ACC checks to ensure that the SDN bus is biased
correctly (in the low state). If the bias is correct, a talk tap is issued.
Otherwise, the branch is fire axed.
Poll Cycle Overflow: Another fault condition detected by the ACC is a
poll cycle overflow condition. The yellow poll cycle LED DS7 is illuminated
signifying a poll cycle has overflowed if, before the next sync tap, all 32
branches do not receive a talk tap and an opportunity to transmit all their
data.
ACC Theory of Operation
The ACC consists of three PC boards (refer to Figure 2-2):
•Main PCB
• Transition board assembly
• Power supply
Main PCB (78581-60200)
The Main PCB is considered the control/drive board. It connects up to 32
branch cables via the Transition Board to provide timed multiplexed
communication links and system synchronization. The circuitry on the
PCB sets up a polling cycle that allows each branch access to the SDN bus
in a sequential manner. Data coming in from one branch is received and
then “broadcast” simultaneously to the remaining branches of the SDN. As
each branch transmits in sequence, the SCC buffers, retimes, and
retransmits the data.
Theory of Operation
System communications is controlled, timed, and synchronized by the
ACC issuing regular system sync messages every 32 milliseconds and a
master sync message every second.
When power is supplied, the MODE switch is sensed for normal operation.
The ACC then issues a SYNC TAP message to all branches connected to
the ACC. The ACC senses the poll timer for 4 ms elapsed time to allow the
instruments to unload their receive buffers and load their transmit
buffers. Then, branch 0 is set up for a TALK TAP message by first sensing
the branch for activity and line state (polarity 1 or 0). If activity is sensed
within a 2.7 microsecond window, or the line is in the logic 1 state, then
the branch is considered faulty (FIRE AXE condition) and is skipped over
without a TALK TAP being issued. However, if no activity is sensed, a
TALK TAP message is transmitted out the branch in which the branch
number is embedded. The branch number is a 6-bit block encoded word
derived from the Block Code ROM. The 5-bit branch binary counter is the
ROM address pointer.
After the TALK TAP message has been transmitted, the ACC turns around
the line drivers and receivers and senses for activity from branch 0 and,
also, turns on the “broadcast” to all remaining branches. The ACC senses
for transmission activity for 12.2 microseconds and will timeout and
switch to the next branch if no activity is sensed. Activity is defined as one
or more positive transitions trapped within the 12.2 microsecond window.
The ACC senses the end-of-transmission by detecting 12.2 microseconds of
continuous silence; no positive transitions for example. The next branch in
sequence is then sensed for silence (no activity) and issued a TALK TAP
message in the same manner. Each branch is polled sequentially until all
32 branches have been issued a TALK TAP message. The last branch
2-13
ACC Theory of Operation
polled at the end of 32 milliseconds must be branch 31 for TALK TAP
messages. If not, the poll cycle is in error and an error flag is set in the
next SYNC TAP message to indicate a POLL OVERLFOW; for example,
system overload or poll sync loss.
Transition Board (78581-61253)
This PCB interfaces from the RJ45 connector to the main PCB. There are
32 ports label from 0 through 31. Port 0 is the master time port for the
central stations. Ports 1 through 24 are bedside ports. Ports 25 through 31
are for other central stations, computers, or mainframes. The transition
board supplies the input/output data from the bedside to and from other
devices.
Power Supply (M2604-60002)
This is a 5V automatic switch power supply. It supplies power for the main
PCB, power on LED and the 5V indicator LED on the rear of the power
supply board.
Power SupplyMain PC Board
Transition Board
Figure 2-2. Internal Components of the ACC
2-14
SDN and ACC System Level Troubleshooting
Section 3: SDN and ACC
System Level
Troubleshooting
Caution
Service and repair of the SDN system components is to be performed by
authorized service personnel only.
SDN Troubleshooting Overview
This section describes a logical approach for service personnel to diagnose
and identify the source of an SDN system problem and to isolate the
problem to the instrument/cable level for service and/or repair. The
troubleshooting procedures are presented simply and logically, and should
be followed in the sequence indicated.
The following troubleshooting procedures are written to minimize
disturbance to system patient monitoring and to avoid (and to determine
the need for) bringing down the entire SDN communications system.
When troubleshooting a new SDN system installation (not a patient
connected SDN system), it may be more expedient to power down the ACC
in order to checkout the cables and swap the Control/Driver PC board in
the ACC. Discretion must be applied according to the constraints of the
situation.
The content of this text presumes that the service person is familiar with
Agilent monitoring instrumentation and has a basic understanding of the
SDN system operation, specifically:
• SDN Architecture and Topology
• Agilent CareNet Controller
• Structure of System Cycle and Poll Cycle
•SDN Status
– Autopoll/SDN
– Offline/Online
–Local/Network
• SDN Interface Board — Functional Block Level
– Activity Detection, Autopoll Enable
– Priority Wires (Upstream/Downstream)
– Last Box Detection, Termination
3-1
SDN Troubleshooting Overview
In addition, service personnel must be aware of the structure of the SDN
system being troubleshot with respect to:
The following abbreviations are used throughout this section:
•Care Units
•Bed Label/Branch Assignments
• IC Tuning
•IC/Branch Assignments
•BS — Bedside Monitor
• CS — Central Station
• LDC — Local Distribution Cable
• LDN — Local Distribution Network
• M/T — Monitor/Terminal; an SDN Bedside
• NT — Network Test
• IC — Information Center
• ACC — Agilent CareNet Controller
• SDC — System Distribution Cable
• XSDC — Extended System Distribution cable
• SDN — Serial Distribution Network
• SDNIF — SDN Interface
A simplified block diagram of the SDN system components is shown in the
following:
BS or CS
SDNIF
LDC
SDC
Wall Box
ACC
SDC LDC
Wall Box
Figure 3-1. SDN Components—Simplified Block Diagram
BS or CS
SDNIF
3-2
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