A computer compatible conversion for printing multichannel analyzers

A computer compatible conversion for printing multichannel analyzers

NUCLEAR INSTRUMENTS AND M E T H O D S 155 ( 1 9 7 8 ) 309-310 : (~ NORTH-HOLLAND PUBLISHING CO. A COMPUTER COMPATIBLE CONVERSION FOR PRINTING...

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NUCLEAR

INSTRUMENTS

AND M E T H O D S

155 ( 1 9 7 8 )

309-310

: (~

NORTH-HOLLAND

PUBLISHING

CO.

A COMPUTER COMPATIBLE CONVERSION FOR PRINTING MULTICHANNEL ANALYZERS MORTON F. T A R A G I N

Department ol Physics, George Washington University. l&ashington, D . ( . 20052. U.S.A. Received 23 February 1978 A simple and inexpensive conversion to allow older style printing multicbannel analyzers to output data in ASCII Keyboard compatible fort0 is described.

Many older style multichannel analyzers and pulse height analyzers use as output devices some type of simple solenoid controlled printing mechanism. With the present use of and availability of small computers, it becomes desirable to interface these printing devices directly to a computer. The following note describes such a technique. The interface circuit described here is for a Nuclear Data Autofinger~), however, the technique will work for any printer using some type of solenoid for printing. The output of the circuit is the same as the standard ASCII keyboard output and can therefore be used to input to a computer in place of the keyboard. Our printer has twelve solenoids, one each for the 10 digits 0 - 9 , one (Tab) for a space between the data for each channel and one (CR) for a new line after ten channels of data have been printed out. The printer solenoids have power applied to 5v

i ~ 2 ~

5 ~

12 identical

4

units

6 7

2 3 4 8

8-9

5v

~

Tab ,

5 6 7 8 9 0 I

9

~.

,Strobe ---5v -gnd

-~1/6

[~

TABLE

I

Required ASCII Code. H O .65 ,bl ,b2 .b3 ~ b 4

2 7K IN4002

one side at all times and are energized when the other side is brought to ground by the multichannel analyzer circuits. This grounding signal is used as input to the interface circuit. The left side of fig. 1 shows the circuits used for converting the grounding signal to TTL signal. There are twelve of these circuits, one each for digits 0-9, one for the Tab and one for CR. The Tab signal is output as a decimal point and the CR as the Return character. The conversion to the ASCII seven bit code is made in part using a Harris HD 165 4 bit encoder2). The required code is shown in table 1. The four least significant bits are obtained using the outputs of the HD 165 as shown in fig. I. The most signifcant bit (b7) is always 0 so it is grounded. Bits 6 and 5 (b6, b5) are obtained from the circuits shown in the lower part of" fig. I. The output strobe from the circuit is pin 4 of the HD 165. Five V is supplied to pin 1 and pin 23 is ground. The above circuit was constructed and tested

.b5

7404

_ ~

.b6

%-~V4 7402

j_

.b7

Fig. 1. Circuit diagram for conversion circuit.

Input b7 0

0

1

0

2 3 4 5 6 7 8 9 Tab (.) CR (Return)

0 0 0 0 0 0 0 0 0 0

most significant b6 b5 b4

0

0

least signilicant b3 b2 bI

0 0 0 0

0 0 0 0

0 0 I 1

0

0

I

0

0

0 0 0

1 1 1

0 1 1

0

I 1 1 I

0 0 1 1

0 0 1 0

0

0 0

310

M.F.

TARAGIN

using a Nuclear Data 2200 MCA with Autofinger outputS). The interface circuit was switched into a terminal in place of the keyboard and was used to send data via an acoustic coupler to an IBM 370 APLSV system. The software used was a standard text editor on the APL system. It was necessary to slow down the data send rate in the MCA in order to allow the IBM 370 sufficient time to dump the buffer at the end of each line.

This work was partially supported by the National Science Foundation under institutional Grant no GU-3287. The George Washington University Center for Computing provided the computer time. References I) Nuclear Data Inc., Schaumburg, Illinois 60067, U.S.A. 2) Harris Semiconductor Inc., Melbourne, Florida 32901. U.S.A.