Sensoray 7429 Manual do Utilizador

Sensoray Model 7429STDbus Sensor Coprocessor

HARDWARE CONFIGURATIONDEFAULTSThe 7429 requires installation of programming shunts to select various options such as I/O port addresses, interrupts, a

I/O PORT MAPPINGThe 7429 occupies two consecutive port addresses in the selected STD I/O space. These ports may be mapped to any address from 00H to

0 I I I2 I I R4 I R I6 I R R8 R I IA R I RC R R IE R R RI indicates shunt should be insertedR indicates shunt should be removedMSN is the most signifi

ALARM interrupt E19 enables alarm interruptSystem interrupt enable E18 routes interrupt request to STD busHARDWARE FILTERSEach channel is provided wit

PROGRAMMINGCOMMUNICATIONProgramming of the 7429 is achieved via a set of built-in commands which the 7429's onboard microcomputer is programmed t

The CRMT and DAV bits are used for communication handshake control as described in the next section. During a coprocessor reset, CRMT is held low — t

'' BasePort% is globally visible within this module'COMMON SHARED BasePort%'7429 base port address'' This subprogram est

COMMANDSThe great versatility of the 7429 is due to its simple but powerful set of built-in com-mands. Commands vary in length depending on the need

Define SensorThis command declares the type of sensor connected to a particular channel. Each sup-ported sensor type is assigned a unique 8-bit senso

TABLE OF CONTENTSBASICS...1WAR

Example: A 350¾ pressure gage is to be connected to channel 7. The gage spec-ification is 3 mV/V at 150 PSI. 3 (mV/V) x 10 = 30.The application req

Read DataThis command returns the most recently measured sensor data from the specified chan-nel. The returned value is scaled according to the decla

Set Alarm LimitsThis command declares upper and lower alarm limits for the specified channel. After declaring limits, an alarm will "sound"

Read AlarmsThis command returns the status the channel alarms. Alarm flags will be returned from either channels 0-7 or 8-15, depending on the comman

Read Board TemperatureThis command returns the temperature of the thermocouple cold-junction compensa-tion sensors (if 7409TB termination boards are c

Set Open Sensor Data ValuesThis command establishes the data value to be returned for each channel if an open sen-sor is detected. Depending on the f

Set Filter Time ConstantThis command establishes a software single-pole low-pass filter for the specified chan-nel. The second command byte specifies

Tare GageThis command tares the strain/pressure gage connected to the specified channel. Gage taring is commonly used to subtract off the load offset

Activate 50 Hz Rejection FilterThis command will cause the 7429 to reject 50 Hertz differential noise on all channels. Upon power-up reset, the 7429

Read All ChannelsThis command returns the most recently acquired data from a block of eight sensor channels. Depending on the command form used, data

Activate 50 Hz Rejection Filter... ...20Read All Channels ...

Calibrate BoardThis command is used to calibrate all 7429 internal standards. All measurements made by the coprocessor are referenced to these standa

NEXT calCode%

CONNECTIONSGENERALAll sensors are connected to the 7429 through the 40-pin ribbon cable connectors P1 and P2. Optionally, sensors may be connected to

no current passes through the sense lines, therefore no voltage develops across the sense wires.Three-wire connectionUsing three wires has the advanta

DC voltage connectionsThere is no need for thermocouples to connect to the POWER+ or POWER- pins be-cause thermocouples contain their own built-in pow

THERMISTORSThermistors (type 10K) have much higher resistance values than RTD's over most of their operating range, therefore a connection identi

4-20 mA current loop connectionsSense+Sense-ShieldSensoray P/N 7408R(+)(-)

CUSTOM RESISTIVE SENSORSThe 7429 possesses the capability of interfacing custom resistive sensors to any sensor channel with the following limitations

D = 1R2 + 17R - 3105where:D is the displacement in millimetersR is the transducer resistance in ohms

This QuickBasic code segment invokes the define channel sensor command for this re-sistive linear displacement transducer:CALL SendByte (16 + 5)'

Limited WarrantySensoray Company, Incorporated (Sensoray) warrants the model 7429 hardware to be free from defects in material and workmanship and per

THERMOCOUPLE THEORYThermocouples are typically formed from two wires having dissimilar metals. The wires are built into a cable having a heat-resistan

COMMAND SUMMARYDEFINE CHANNEL SENSOR - declare sensor type connected to a channelCustom resistive sensors only:command: (16 + CHAN),(SENSOR DEFINITION

READ BOARD TEMPERATURE - read 7409TB temperature7409TB (channels 0-7):command: (64)response: (TEMP MSB),(TEMP LSB)7409TB (channels 8-15):command: (65)

SET OPEN SENSOR VALUES - establish data value in event of open sensorChannels 0-7:command: (80),(OPEN SENSOR FLAGS)response: NONEChannels 8-15:command

SENSOR TABLESSensor definition codes and data scale factors:SENSOR TYPE CODE DATA SCALING per bitVoltage±100 mV f.s. 17H 5 µV±500 mV f.s 16H 20 µV±5

4-20 mA 11H 0.01% (4mA=0%, 20mA=100%)Gage (pressure/strain)Š120¾ 12H * defined by programmerDisabled channel13H * not applicableBACK COMPATIBILITYIn a

TIMINGThree timing parameters are important from a system integration viewpoint: channel scan rate, communication latency, and host processor speed.

byte. This analysis ignores any additional time consumed by the host processor.The read all channels command consumes 740 microseconds maximum as fo

BOARD LAYOUTE26E24E22E27E25E23E21E20E18E19J1E17E1E2E3E4E5E6E7E8E9E10E11E12E13E14E15E16P1P2

INTRODUCTIONFUNCTIONAL DESCRIPTIONThe 7429 interfaces sixteen process sensors directly to the STD bus. Each of the sixteen sensor channels may be ind

Measurement time per channel 16.66 msec/channelChannel settling time 5 msecStrain/Pressure gage excitation 10VDC, pulsedResistive sensor excitation 13

SensorsSensor Type Range Resolution Accuracy Noise, 1-sigmaThermocouplesE -270C to 990°C 0.1C 0.2°CJ -210C to 760°C 0.1°C 0.2°CK -270C to 1360°C 0.1°C

Strain/Pressure (4-wire bridge) Š 120¾ -100 to +100 mV 5 µV 10 µVDC Voltage Input Range 1 -5 to +5V 200 µV 0.40 mV 0.75 mV Range 2 -500 to +500 mV