2014 7th Cairo International Biomedical Engineering Conference Cairo, Egypt, December 11-13, 2014
A Novel Approach for Remote Diagnosis and Troubleshooting for Lab Instruments Ashraf Nader and Ayman M. Eldeib Systems and Biomedical Engineering Department, Faculty of Engineering, Cairo University, Giza, Egypt e-mail:
[email protected] Nowadays many critical care and laboratory (lab) equipment manufacturers are offering remote diagnosis services for their products by the aid of built-in communication port(s) i.e. USB, serial (RS232), network, and others that can be connected to a PC. Using a special interface software protocol, the instrument and PC can communicate and interchange data. Remote diagnosis significantly shortens repair time, avoids downtime by taking advantage of predictive methods, and provides general diagnostic assistance [4]. However software packages are not often available or affordable for most instruments especially in developing countries. The situation is more drastic for old or discontinued but still in service instruments with customers trying to get maximum benefit out of them; such condition urges us to find a feasible, low cost, and compact design solution.
Abstract―The use of remote diagnosis and troubleshooting are widely used nowadays to improve instruments’ uptime and minimize workflow interruption. However, such feature is not used in many critical care units and/or laboratories either due to limited capabilities and access offered by manufacturers of such equipment or because of high cost for interface software packages especially for developing countries. The negative impact is more felt in laboratories with old instruments lacking remote connection ports but having an embedded maintenance and/or troubleshooting software. This paper describes a direct access remote diagnosis and troubleshooting for the input and output devices of a critical care and laboratory instrument using a flat data cable, an 8 cm x 10 cm built-in printed circuit board designed for this purpose, a standard parallel cable, and a control software. The main advantage of this approach is its low cost, compact design and simple implementation besides being convenient and suitable for other instruments possessing input/output devices with the same specifications. Implementation of the software and hardware related to accessing the instrument’s membrane keypad and display using a PC has been successfully accomplished and tested leading to the use of all PC communication capabilities including remote connection and access. By integrating all hardware components, the prototype system was capable of remotely diagnosing and controlling the instrument on realtime basis.
The main idea lies in bypassing the instrument’s standard communication ports used for remote access and getting direct access to the machine’s input and output devices i.e. membrane keypad (MK) and vacuum fluorescent display (VFD) respectively in our case. By developing a suitable control/data (C/D) flat cable capable of sending required keypad control instructions and receiving displayed data together with proper hardware and electronic components, a real-time remote diagnosis and troubleshooting solution is possible.
Keywords: Critical care instruments, direct remote access, laboratory equipment, remote diagnosis, troubleshooting
I.
A comparison between available Traditional Remote Access (TRA) methods and the proposed approach reveals the main points of strength for the Direct Remote Access (DRA) technique over traditional ones. Among such considered comparison criteria are access type, user customization, interface software (s/w) availability, and cost. Table Ι summarizes previously mentioned comparison criteria.
INTRODUCTION
The principle of remote diagnosis emerges to overcome high cost and difficulty of transportation to far territories, scarcity of service personnel at suppliers, also offering technical support at unreachable regions due to natural disasters, harsh weather conditions or at war time [1-2].
Access type – complete access to instruments is a desirable feature which allows the operator to perform a range of tasks, and can benefit from all system information i.e. data results, warning and error messages, and operating menus, together with complete real time interaction. TRA is usually limited and restricted to what is offered by the manufacturer and to other commercial aspects. TRA is mostly used as a Data Management System (DMS); mainly for data results, data flags, and patient demographics.
Telemaintenance is used in the industrial field based on remote supervision and activation of given equipment in an industrial environment [3], benefiting from the technological evolution in the field of electronics and telecommunication. The medical field applies same principle to medical instruments: mainly life supporting categories, and 24hrs running systems. The use of remote diagnosis technique in the medical field greatly resolves problems related to frequent medical staff turnover and shifts, lack of experience and training, and aids in fast intervention without the need to physically access the remote location [3].
User customization – lab equipment users' demands and requirements vary dependent on scope of interest and kind of personnel. Users are interested in patient results, system
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TABLE I.
TRADITIONAL AND DIRECT REMOTE ACCESS Types of Remote Access Techniques Comparison Criteria Traditional Direct
Access type
Limited
Complete
Applicability
Special commun. ports
Direct access
User customization
Usually not possible
Possible
Interface software
Specific protocol
Open source
Interface s/w availability
Rare for obsolete inst.
Available
Beneficiary instruments
Modern
Versatile
Expensive
Cheap
Usually restricted
Possible
Cost Software upgrading
running machine requiring fast service intervention, the blood gas analyzer (BGA) was chosen to apply our Direct Access Remote Diagnosis and Troubleshooting (DARDT) design. The preliminary results of the design after testing indicate normal and safe working conditions. No signs of degradation or interference to the BGA functionality or to any of its components were observed. The DARDT design could be used by other lab or critical care instruments possessing input/output devices with the same specifications. II.
MATERIALS AND METHODS
®
248 (RL248) pH/blood gas analyzer Rapidlab manufactured by Siemens [7] was chosen to implement and test the DARDT technique. The implementation procedure passed through five main stages. First, the BGA was prepared for direct remote accessing with necessary modifications carried out. Secondly, required C/D flat cable for the analyzer’s MK control signal and display data acquisition was customized. Thirdly, the C/D flat cable was connected to the interface PCB designed to interface with the PC: receiving control signals to trigger the analyzer’s MK control PCB and sending display data to be viewed on the PC display. The PC used could be a dedicated one or any available at time of need. The PCB position at the back cover of the analyzer was carefully selected to ensure both non interference to any internal integrities and ease of connection to PC. Fourthly, a standard parallel port (SPP) cable was used to connect the analyzer to the PC. Finally, the control software was installed on the PC for the system ready for use. Fig. 1 shows all five stages with hardware components required for implementation. The following sections describe main components used at each stage.
calibration, and quality control data, while maintenance personnel seek information related to system performance, error messages, and diagnostic features. By getting complete access to the instrument one can get the received data tailored-made to suit his needs by simple programming. Interface s/w availability – one of the main challenges facing owners of obsolete instruments in developing countries seeking remote access and who can afford to purchase the original interface software, is its availability. Most probably manufacturers' interface software for such instruments is scarce or discontinued. The DRA approach significantly resolves the problem and adds a new desirable feature to the customer. Cost – a vital aspect of any system under consideration is its price versus capabilities and features. A survey of fourteen blood gas analyzers available in the UK market carried out in 2006 by the Purchasing and Supply Agency (PASA) states that cost of a connectivity system for a single BGA is up to $5000 [5]. Hospitals in developing countries often operate on limited funds [6], which make such high purchasing cost worthless the benefit they get for a single instrument. The preliminary cost for the suggested DRA is only $150 for electronic components and PCB fabrication, plus cost of a PC if one is to be dedicated for such purpose.
A. Analyzer Modifications Only two minor modifications were performed to the analyzer. The first modification was the replacement of the one row 14pins MK male socket in the analyzer’s internal control PCB with a two row 28pins male socket of the same type. This change allows for dual connection to the analyzer’s MK and DARDT’s interface PCB via the C/D flat cable. Fig. 2 shows the 28pins male socket after replacement.
Due to its significant importance as being one of the major lab and critical care diagnosis instruments, and a 24hrs
The second modification was a 1.5 cm x 4.5 cm slot at the analyzer’s back cover to fit the 8 cm x 10 cm interface PCB. Fig. 3 shows the back cover with the interface PCB
Fig. 1. Schematic diagram showing five stages and hardware components required to implement the DARDT technique. B. C/D flat cable C. Interface PCB D. SPP cable E. Control software A. Analyer modifications
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assembled at the generated slot.
compared to a VISA card.
B. Keypad Control signals and Display Data Acquisition A 45 cm long flat cable with 40pins female socket is used to connect one of two rows of the 28pins male socket in the modified internal control PCB and VFD to the interface PCB. The cable is composed of two paths; 26pins male and female dual socket cable connected to the VFD and VFD control PCB of the analyzer uniting with a 14pins female socket cable connected to the MK male socket of the modified internal control PCB to form one cable. Fig. 4 shows a photo of the C/D flat cable. Flat cables are widely used in data transfer especially in PCs due to their flexibility, durability, and ability to exist in narrow spaces.
D. Computer Interfacing A standard DB25 male-to-male 1.8 m long parallel port cable was used to interface the BGA to the PC. SPPs allow the input of 13 bits via the data and status lines, and the output of 4 bits via the control lines. The SPP input pins are directly connected to the data and control ports of the VFD [10-11], while the output pins of the SPP are connected to the 4-to-16 line decoder used to trigger one of the 16 phototransistor at a time for each specific keyboard button press. The triggered phototransistor activates the MK of the BGA simulating pressing on same MK button causing the BGA to respond to such action in return.
To test for displayed patterns before programming the control software the Tektronix logic analyzer, model TLA5201B, ver. 5.6, USA and the Agilent Technologies logic analyzer, model E9340A, ver. 1.21, were used to acquire the VFD data to be analyzed, the proper frame rate was selected, and known display patterns were matched.
E. Control Software The control software for DARDT was developed by the aid of Microsoft Visual C++ of the Visual Studio package. The software translates the VFD data picked up by the interface PCB and displays it on the PC display [12]; the software then waits for any keypad stroke command by the user before reverting back to the VFD data signal for any new screen updates that might occur. In this manner realtime access to the BGA is guaranteed.
C. Interface PCB components and Design The interface PCB is composed of a 40pins male socket from one side, and a DB25 female socket from the other side. The 40pins male socket of the PCB is connected to the C/D flat cable; the other DB25 female socket is for PC connection by the aid of a standard parallel port cable. Only two kinds of electronic components were used; namely the CD74HCT4514 4-to-16 line decoder [8], and the TLP521GB phototransistors with optically coupled isolators [9] arranged in an array of 16 units. The decoder receives the desired control signal from the interface software through the parallel port to simulate keypad strokes. Based on the decoder's inputs only one addressed output is activated to 5V corresponding to the same keyboard key pressed by the user from the PC connected to the analyzer. The decoder's high output triggers the phototransistor connected to the corresponding key in the analyzer's MK internal control PCB simulating the press action performed by the BGA's user. A series of resistors (R1 through R16) were connected to the phototransistors’ primary side to step-down the 5V high output voltage of the decoder to the typical 1.15V triggering voltage for the phototransistors. The design was meant to be as compact as possible with minimum components on board. The circuit schematic diagram for the interface PCB is shown in Fig. 5. The interface PCB was intended to be relatively small, only 8 cm x 10 cm. Fig. 6 shows a photo of the interface PCB
III.
RESULTS
Several tests were carried on the BGA by first running the control software then plugging the parallel cable to the analyzer. All tests performed reveal normal and safe operation, no signs of disturbance to any of BGA status. Control signals simulating MK strokes are satisfactory with almost no delays. BGA transferred screens displayed on PC does not show significant distortion. Despite that the picked up VFD data require further processing and enhancement to capture all BGA screens with exact alignment, and better transmission rates. It is expected that the new version will overcome such aspects. Fig. 7 shows a snapshot for the DARDT main menu. Fig. 8 shows a photo of the RL248 BGA screen and MK. A trial for remote connection to the PC interfaced to the BGA was successfully done using the standard LAN connector found in most PCs, and the Windows remote desktop connection capability. The two minor modifications performed to the RL248 BGA and discussed earlier were intended to have minimum influence on the analyzer's internal circuitry as not to hinder
to interface PCB to VFD
to MK control PCB
Fig. 2. BGA internal control board modified with two row 28pins male socket (circled).
Fig. 3. BGA back cover with interface PCB (circled) assembled at the slot.
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Fig. 4. Photo of the control/data (C/D) flat cable.
to VFD control PCB
to C/D flat cable to VFD module to MK control PCB
Fig. 5. Interface PCB circuit schematic diagram.
Although the SPP is considered outdated by some parties, most PCs are still being equipped with. The reason for choosing this port rather than other serial ports is the need for multiple input/output channels working at any given time, thus requiring minimal external circuitry [12], besides ease of software programming and control. SPP is also faster than serial ports, but main disadvantage is its need for more number of transmission lines that's why it is not used in long distance communications, which is not the case in the proposed design where remote accessing is achieved using Internet connection.
any claim for acquiring CE marking conformity and/or FDA approval once an assessment is required. Such conclusion is reached on basis that the used technique is a device observer with direct connections and no power components used, except for the MK external control decoder, thus having minimal interference, not affecting environment and health safety nor leading to biologically hazardous risks [13-14]. IV.
DISCUSSION
To the best of our knowledge the discussed approach was not proposed before for lab equipment in general or BGAs in specific, that is why it is considered a novel approach.
Switching to use other serial or USB ports will be considered especially for laptops connectivity as they usually lack parallel ports.
The aim of this work was developing an effective, simple, compact, and low cost direct access for remote diagnosis and troubleshooting, and thus overcoming the need for original manufacturer’s remote software package especially for old analyzers, and extending analyzers capabilities for those with unavailable remote software packages. By this means added value for BGAs' users is originated. The proposed solution is intended to remotely access one analyzer at a time. Trials for accessing multiple analyzers at the same time were not validated.
The DARDT design takes into account not using any components that may cause noise signals and so assuring safety to the instrument; that is why optically coupled isolated phototransistors were used to isolate and delimit PC keyboard input control signals to the BGA in case of any anomalous behavior. By connecting the BGA to the PC and succeeding to log on via local networks a remote connection is achieved. This can then be extended to include Internet access from any PC with complete consideration for security and privacy. As a future work, the same DARDT technique can be applied to other advanced display types i.e. touch screens. Some modifications will be carried on the interface PCB to be converted into a universal remote access interface capable of handling extra data/control lines from any type of
Fig. 6. Photo showing interface PCB size compared to a VISA card.
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Fig. 7. RL248 BGA DARDT main menu snapshot.
Fig. 8. Photo of RL248 BGA screen and membrane keypad.
displays and keypads. The use of a microcontroller will lead to better data routing, minimum control lines, and allow for switching to the more commonly used ports i.e. Serial and/or USB ports respectively. The used control software can be improved also to include automatic or user-defined data and results archiving, viewing error log history will be possible as well. A prioritization feature for the BGA's MK input over the DARDT control software could also be added. By this means the technique can be used as a general purpose DARDT facility. V.
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CONCLUSION
[4]
The use of remote access and remote control software in recent years has further enhanced the ability of the help desk personnel to assist, troubleshoot, and solve problems remotely [15]. As increasingly more medical systems are connected via telecommunications, networks and the Internet, the help desk can perform remote troubleshooting, diagnostics, and system upgrades [15].
[5]
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[7]
It is evident that telemaintenance and remote diagnosis and troubleshooting is becoming the most convenient solution for many medical instruments proactively increasing reliability and uptime. The biggest beneficiaries are 24hrs running instruments and those requiring fast service intervention i.e. blood gas analyzers.
[8]
[9]
By acquiring a cheaper solution than traditionally used ones, besides being an easy to implement easy to use technique, the greater the benefits, the more the users, the better the healthcare quality provided, the lesser the analyzer's down time, and finally the lesser the patients stay at hospitals.
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[11]
Realizing such fact the authors have managed and implemented a new approach for remote diagnosis and troubleshooting employing simple electronic components to get a real-time remote diagnosis system. It can be extended to other instruments with same input/output platforms. It might also be standardized to virtually serve any instrument regardless of its complexity, brand, or model.
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ACKNOWLEDGMENT The authors would like to thank Eng. Yasser Kenawy, Eng. Osama Riyad, Eng. Aser Mehrez, Eng. Ayman Anwar, and Eng. Mahmoud Eid for their assistance. 978-1-4799-4412-5/14/$31.00 ©2014 IEEE 5
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