WO1988006827A1

WO1988006827A1 - Centralized inventory apparatus for a plurality of printed circuit boards in a magazine

Info

Publication number: WO1988006827A1
Application number: PCT/SE1988/000099
Authority: WO
Inventors: Bror Thomas Tullholm
Original assignee: Telefonaktiebolaget L M Ericsson
Priority date: 1987-03-04
Filing date: 1988-03-03
Publication date: 1988-09-07
Also published as: SE8700912L; SE456709B; SE8700912D0

Abstract

An apparatus for making an inventory of printed circuit boards (K1-K30) placed in a magazine (M) is provided. A given space on each board is reserved for a programmable memory (EP1) and a first microprocessor (MS1-MS30). The back plane of the magazine is divided into a plurality of part areas (BP1-BP4), where each such area corresponds to a board. A plurality of connection points (S1-S5) in each part area gives information as to the actual position of the board in the magazine. The correct position of the board is stored in the memory (EP1). The first microprocessor compares the actual position with the correct position and sends the result to a second microprocessor (MP) for the entire magazine. The first microprocessor (MS1-MS30) reads out remaining information about the board and sends such information to the second processor (MP).

Description

CENTRALIZED INVENTORY APPARATUS FOR A PLURALITY OF PRINTED CIRCUIT BOARDS IN A MAGAZINE.

TECHNICAL FIELD

The present invention relates to an apparatus for centralized inventory of a plurality of printed circuit boards (PCB) provided with electronic components, the PCB's being placed conventionally in a magazine. More specifically, an apparatus is intended for making an inventory of PCB's included in magazines for a telephone exchange.

BACKGROUND ART

By the expression "making an inventory" is intended in this context an examination of each of a plurality of PCB's in the magazine with respect to its position in the magazine, its type, name and remaining information, e.g. its circuit layout, that can be stored in a memory on it. Modern telephone exchanges constitute systems where the different system components are soldered to PCB's arranged in magazines, which in turn are stacked in racks. The total rack space here is less than in earlier electromagnetic exchanges, but still contains a large number of components and thus a corresponding number of PCB's.

It must be possible for a service man either completely or partially to make an inventory of the units included in the system. In a known method of performing such an inventory, each PCB is provided with a Bar Code containing the above- mentioned information as to PCB type, name etc. The serviceman performs the inventory by manually using a light pen to read the PCB's one after the other. If a large number of PCB's are to be read in the exchange, this can become time- consuming and expensive.

DISCLOSURE OF INVENTION

The above-mentioned disadvantages lead to the thought of making an inventory centrally and being able automatically to bring the desired information together, e.g. to a centrally placed terminal with a keyboard and display screen. It would, for example, be desirable to make an inventory at a service station in a "central office" remote from the local exchange or exchanges.

The object of the present Invention is therefore to provide apparatus for centralized inventory of a plurality of PCB's in one or more magazines included in a telephone system, by automatically collecting data from each of the PCB's in the magazine or magazines.

To this end the apparatus is characterized as disclosed in the characterizing portion of claim 1.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be described in more detail, and with reference to the accompanying drawing, on which

Figure 1 is a schematic front view of a magazine containing a plurality of

PCB's,

Figure 2 illustrates in more detail the apparatus in accordance with the . invention in a PCB seen from one side, and with its associated back plane in the magazine seen from. its front,

Figure 3 schematically illustrates a back plane in the magazine with a plurality of voltage connections,

Figure 4 is a simplified block diagram of a store and a microprocessor included in the apparatus according to Figure 2.

BEST MODE FOR CARRYING OUT THE INVENTION

Figure 1 is a direct front view of a magazine M with a plurality of PCB s, Kl, K2, ... K31 inserted therein, where only the front end walls of the PCB's are visible in the figure. The PCB's K1-K31 take up 31 positions numbered 01-31. If the magazine has been charged with the PCB's correctly, the PCB Kl will be inserted in position 01, K2 in position 02 etc. For certain reasons, however, e.g. unexperienced personnel, forgetfulness etc, one or more PCB's may be inserted in the wrong compartment (position), although normal functions in the system to which the magazine M pertains operate satisfactorily even so, while seldom used functions are inoperative. In the end, however, the system which has one or more wrongly inserted PCB's will not operate as intended. This can be discovered by making an inventory of the PCB's.

In accordance with the present invention, space has been reserved on each PCB for making an inventory of them. An EPROM-type programmable memory EP1, EP2, ... EP31 has been arranged in this space on each of the PCB's K1-K31. Each of the memories EP1-EP30 is connected to an associated microprocessor MSI, MS2, ... MS30. Each memory EP1-EP30 contains information on the PCB to which it is connected which is unique for that particular PCB. The information is stored in encoded form conventionally and may comprise a) PCB type overhaul status b) PCB name/denotation c) Remaining information, e.g. circuit layout for the particular PCB.

Each of the microprocessors MS1-MS30 is connected to its associated memory for reading out and processing the stored information according a) - c) above. The microprocessor MS1-MS30 on each PCB is connected via the back plane in the magazine to a special two-wire data bus Bl for data transmission (SDA) and clock pulse transmission (SCL) to a main processor MP connected to the microprocessor PCB K31 in the magazine.

The microprocessors MS1-MS31 can be of the single chip type, of the Philips

PCB 8400 family, and the microprocessor MP of the type MC 68070 or the like.

2

TThhee ddaattia bus Bl is in this case of the so-called I C-type (two-way communi- cation).

The position of the memory EP1 and associated microprocessor MSI on the PCB Kl is illustrated in more detail in Figure 2. A terminal block PI on the PCB is associated with the connections for the remaining (not illustrated) components on the PCB Kl. In this embodiment, seven jacks in a second terminal block P2 have been reserved for the microprocessor MSI, namely five jacks J1-J5 for connecting certain input ports (see Figure 4) of the processor MSI and two jacks for connecting to data out - data in and the clock input of the processor MSI, which constitutes an extra data bus. The jacks J1-J5 are intended for connection to the pins S1-S5 of the back plane BPL1 of the PCB Kl, where certain pins are live (see below, Figure 3). The jacks 36 and J7 are intended for the pins S6 and S7 for connection to the two- way bus Bl.

Referring now to Figure 3, it will be seen how a constant voltage to certain pins in the back plane is arranged. The parts of the back plane lying opposite the different PCB's KI-K4 are denoted by PBL1-PBL4. Within the part PBL1 for the PCB Kl the pins S1-S5 are utilized in this case for connecting to the jacks 31- J5 of the PCB Kl and the pins SI, S7 for connecting to the pins 36 and 37. In this illustrated example the pin S4 has been connected to the constant voltage +5V while remaining pins S1-S3 and S5 are at zero volts.

The five pins correspond to a given binary word of five bits, in this case 00001 for the PCB Kl. In the back plane part PBL2 the pin S3 is conected to +5V, the corresponding binary word being 00010. For the back plane parts BPL3 and PBL4 the corresponding binary words will be 00011 and 00100.

Each part of the magazine back plane associated with a given PCB position is thus encoded with a certain binary number which unambigously determines the position of the PCB in thε magazine. As previously mentioned, the five pins Sl- S5 of each of the parts BPL1-BPL5, BL6-BPL30 are connected to a micro- processor MS1-MS30 on each of the PCB's K1-K30, and accordingly give information as to the position of the PCB in the magazine.

Figure 4 illustrates in more detail the memory unit EP1 and its connections to the microprocessor (the subordinate processor ) MSI on the PCB Kl. The unit EP1 constitutes and EPROM in which there has been programmed PCB POSITION, PCB TYPE, OVERHAUL STATUS and "REMAINING INFORMATION". PCB POSITION denotes the position in the magazine, i.e. 01, where the PCB is to be inserted, and shall agree with the PCB position 01 according to Figure 3, i.e. the value 00001. This is correspondingly applicable for remaining PCB's in the magazine. The microprocessors MS1-MS31 are in this case so-called micro-control circuits of the type PCF 84C20 (PHILIPS), each being an 8-bϊt single chip microcontrol circuit/arithmetic processor in CMOS with 2KROM/64 RAM bytes. Such a circuit has three ports P0, PI and P2. In this case, port P0 has five utilized inputs P_QQ, P,-., , P_Q2 and P_Q. , respectively connected via the jacks J1-J5, and the pins S1-S5 to the magazine back plane for sensing 0V or +5V. In this case, only five of 8 bits (ports) on the circuit 84C20 are utilized. The port P2 with the pins P20-P23 is here divided up for transmission of serial data (SDA) over the bus B, , and the pins P22, P23 are connected to a data bus d from the memory unit EP1. The port PI (the pins P, _n - Pi y) can be entirely or partially utilized for connecting to an address bus a on the store unit EP1. The clock port SCLK is two-way and connected to the bus Bl.

The memory unit (EPROM) EP1 has the address inputs A_Q - A connected to the address bus a for indicating the respective memory cell in EP1 by the circuit MSI. The memory content in the respective space is read out via the data outputs D_Q - D-r and over the data bus d to the circuit MSI.

The microprocessor MP, which is the main processor, is suitably a 16-bit processor of the type SCC 68070 (PHILIPS) or the like. Its central unit collects and processes data from the bus Bl on commands from the subordinate processors MS1-MS30 (via SDA). In addition, on a command from the service¬ man, the processor MP can send processed information via a serial I/O interface in the form of asynchronous data.

2 As mentioned above, the bus Bl is a so-called I C bus (PHILIPS' specification) and can transmit data via two-wire communication (SDA serial data, SCL serial clock) between units connected to the bus Bl. Each unit can be recognized by a unique address, the unit comprising a microcomputer and a memory. Data communication (as well as clock pulses) can take place in both directions. A processor can, as a master unit, initiate data transmission on the bus (Bl) and generate the clock signals. In this case another processor, which is connected to the bus and is addressed, constitutes the slave unit. Since the bus Bl is a multiple master bus, several processors can be connected as master units and these may be individually recognized by their own uique addresses. In the present case, the master unit is the microprocessor MP and the slave unit consists of the microcontrol units MS1-MS30. When making an inventory of the PCB's K1-K30 in the magazine, a command is sent from the main processor MP. This processor has in turn obtained a command from the serviceman, who may be a long distance away from the telephone exchange in which the magazine is placed.

The command from the main processor MP may be suitably sent to all the subordinate processors MS1-MS31 for activating these to start the inventory process. For the PCB Kl this means that a signal is sent from its associated subordinate processor MSI via the address bus a to point out the memory space PCB POSITION in EP1. The binary value 00001 is then read out, and a comparison with the value of the position (01) in the back plane stored in the processor MSI then takes place. After this comparison has been made, the result thereof is sent via SDA to the main processor, e.g. as "1" for agreement, or otherwise as "0". Since only one bit position is required for the result of the comparison, the result from all subordinate processors MS1-MS31 may be sent over SDA to the main processor MP.

As an alternative, the values for the PCB positions may be stored in the main processor MP, and the comparison carried out in this processor. The subordinate processors MS1-MS30 then only read out the binary value for the respective PCB position and expedite it to the main processor MP.

Remaining inventory of the PCB's is carried out after the above-mentioned operations have been performed by the subordinate processors MS1-MS30. Pointing out thus takes place of the memory space for PCB TYPE, OVERHAUL STATUS and REMAINING INFORMATION. The information which is to be sent to the main processor MP is here more exhaustive and this is therefore sent in sequence beginning with the PCB Kl, and then PCB K2 etc until all the store units have sent their stored information to the main processor MP, so-called

2 "arbitration", - see the specification of the I C bus. Transmission between the main processor MP to the data operator can take place on a special service channel if the traffic between the local exchange and the central exchange is voluminous, otherwise normal transmission paths can be utilized.

Claims

1 Apparatus for centralized supervision and inventory of a plurality of printed circuit boards, to which are connected electronic functional units, particularly for making an inventory of units in a telephone system, the circuit boards being mounted in given places (01-04) in the magazine (M) which has a back plane with wire connections between the printed boards and connections' means between the boards and the back plane, characterized a) in that the back plane (BP) is divided into a plurality of part areas (BP1- BP4) for each of the printed boards (K1-K4) consisting of a plurality of contact points (SI, Jl, S2, 32, S3, 33) where one or more connection points are activated for defining the position of the part area in the back plane (BP), b) by a first microprocessor (MS1-MS30) arranged on each of the printed boards and connected to associated connection points (SI, Jl, S2, 32) for obtaining information as to the position of the board in the back plane of the magazine, c) by a programmable memory unit (EP1-EP30) arranged on each printed board for storing data on it as to what type it is, its denotation etc, the unit being connected to the first microprocessor for feeding out n data concerning the board on command, d) by a second micoprocessor (MP) for the entire magazine, which via a two- 2 way data bus (I C) is in communication with the first microprocessor (MS1-

MS30) on each of the boards, and which, on a given operator command, activates the first microprocessor on each board for sequentially sending to the

2 sseeccoonndd microprocessor over the data bus (I C) n data concerning each of the boards.

2 Apparatus as claimed in claim 1, characterized in that the first micro¬ processor (MS1-MS30) obtains, via the activated connection points, a first value denoting the actual position of the associated board (K1-K30), that a given second value is stored which denotes the correct position of the board in the magazine (M), and that a comparison is made in the first microprocessor (MS1- MS30) between said first and second values, the result of the comparison being sent further to the second microprocessor (MP), subsequent to which said data concerning each of the PCB's are sent to the second processor (MP) as a response to said operator command.

3 Apparatus as claimed in claim 1, characterized in that each of n part areas (BP1-BP4) on the boards comprises a plurality of pins (S1-S5) arranged in a matrix where one or more pins are connected to a constant voltage (+5V) while remaining pins are earthed, the positions of the live pins in the matrix determining a binary value representing the position of the board in the magazine.