Omega DPF75, DPF78, DPF76 manual Serial Input Commands, Unit will Recognize a Decimal if ONE is

SERIAL INPUT COMMANDS:

To get a unit on line you must address it by its device number. This is done by typing DXX(S), XX= device number. The unit comes on line and echoes back DEVICE# XX. Insure that "DEVICE# XX:" is received before requests are sent. The unit is now ready to receive a command or string of commands separated by a space. A carriage return (enter) will enter the commands and processing of requests begins. The carriage return (Hex Code "D") puts the unit "off line" after data is processed.

COMMANDS:
EP	Unit will enter program mode.
DA	Unit will display (transmit) Count A.
DB	Unit will display (transmit) Count B.
DR	Unit will display (transmit) rate A.
KA	Unit will display K-factor A.
†*KA(S)XXXXX....		Unit will load K-factor A
with entered number.
KB	Unit will display K-factor B
†*KB(S)XXXXX....		Unit will load K-factor B
with entered number.
PA	Unit will display Preset A.
†PA(S)XXXXX....		Unit will load Preset A with
entered number.
PB	Unit will display Preset B
†PB(S)XXXXX....		Unit will load Preset B with
entered number.
RA	Counter A will reset
†*RA(S)XXXXXX...		Unit will set Counter A to
entered number.
RB	Counter B will reset.
†*RB(S)XXXXXX...		Unit will reset Counter B to
	entered number.
*THE UNIT WILL RECOGNIZE A DECIMAL IF ONE IS
PLACED IN ANY OF THESE DATA VALUES.
†THE UNIT WILL ONLY RECOGNIZE THE LAST FIVE
DIGITS ENTERED (SIX DIGITS FOR RA & RB).
The following is an example of requests and responses:
Transmit from terminal Receive from unit
		(s)=Space
D5(s) [Unit #5 Activated]			DEVICE# 5:
PA(s)12345(s)PA			PA 12345 PA
KA(s)1576(s)KA			KA 1576 KA
KB(s)6751(s)KB			KB 6751 KB
RA(s)RB[RETURN]			RA RB
(UNIT PRESETS AND A & B K-FACTORS ARE SET AND
BOTH COUNTERS ARE RESET)
			12345
			1576
			6751
SERIAL INTERFACE OPERATION:
Data is received and transmitted over standard EIA RS232 or
RS422 levels. Each ten bit character is made up of a start bit,
seven bit ASCII code, a parity bit and a stop bit. Device
number, baud rate, parity and strobe list are entered in the
program setup mode and will remain in memory even if power
is lost.

The input impedance of RS232 is 3KΩ to 7KΩ worst case. The terminal addressing the unit must be capable of driving all loads in the loop. The input impedance of RS422 is much higher and there should be no problem driving as many as 99 units. The transmit line remains in a high impedance "off" state until addressed. Only one unit is to be on line at a time!!! More than one unit on line could damage the unit or destroy the transmitted data.

When the unit is active (on line) it will operate in a full duplex, echo back mode, so that data sent from the terminal will be transmitted back for verification. When the unit is "on line", use the proper serial transmit commands to request data or set a new value. Up to 80 characters of data can be linked together and transmitted to the unit in a string as long as there is a space between the commands. If an error is made, a correction can be made by back spacing and retyping correct data before the return (enter) is sent. Once a return (enter) is sent, the unit begins processing the data and will transmit the requested data on a non-priority basis over the data transmit line. A keypad entry or incoming data will halt the data communication cycle. Therefore, there should be a pause after data is requested to insure that all data has been transmitted before making another request or addressing another unit. If the unit is not busy, it should not take longer than 300 msec to process each request. To find the cycle time to process and transmit a request, calculate the bit transmit time by using this formula: [(1⎟ baud rate) x (80) + .005] x number of requests made. This time will be extended if the unit must service the front keypad. If transmission has not started within two seconds after data is requested, it can be assumed that there is a problem. The unit transmits a carriage return and line feed after each data value. Any new commu- nication must be started with DXX(S) (device number and space).

RS232/RS422 - IBM-PC INTERFACE:

The following program is for IBM basic to set up RS232/RS422 on serial port (#1) at 300 baud. Run this program after connecting the serial interface connections.

10 SCREEN 0,0:WIDTH 80

20 CLS:CLOSE

30 OPEN "COM1:300,n,7,1,CS,DS,CD" AS #1

40 ON ERROR GOTO 110

50 B$=INKEY$

60 IF B$< >"" THEN PRINT #1,B$;

70 IF EOF (1) THEN 50

80 A$=INPUT$ (LOC(1),#1)

90 PRINT A$;

100 GOTO 50

110 RESUME

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