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BASIC I/O AD Hardware User Manual

Chapter 3

BIO4AD, BIO8AD and BIO16AD Products

Chassis Setup

Figure 3-1 Connectors, Switches, and Indicators

Figure 3-1 Connectors, Switches, and Indicators

During the setup phase of a BASIC I/O AD system, the chassis is given specific values for unit address, analog/digital separator, network baud rate and protocol pass type. A momentary push-button and seven-segment display provide access to these parameters. Figure 3-1 shows the location of these components labeled Setup Push-Button and Sequential Display.

Function Addresses

Each Host instruction includes an address made up of two hexadecimal characters (00H to FFH). At any BASIC I/O AD network connection 3 different types of functions can be performed, each with its own unique system-wide function address. There are two BASIC I/O AD addressing modes, OFFSET and VARIABLE.

Offset Mode

Units are shipped in the OFFSET mode where only the Master Unit Control address needs to be set (with a range of 00H to 3FH). The remaining function addresses are automatically calculated and set based on the Master address.

Function Abbreviation Function Address Sequential Display
Master Unit Control MC 00H (0) U0=00
Master Unit Digital I/O MD 40H (64) U1=40
Master Unit Analog I/O MA 80H (128) U2=80

The OFFSET addressing mode is more convenient to use, as only one address setup is required for each network connection. For example changing the Master Unit Control, MC, from 00H to 03H will automatically cause MD=43H; MA=83H.

Variable Mode

In the VARIABLE mode, function addresses are independent of each other, and can range from 00H to FFH. For this mode, each function, MC, MD, and MA must be entered. As long as addresses are not duplicated, they can take on any of the 256 possibilities. The VARIABLE mode must be used with some software packages and systems of more than 64 BASIC I/O AD network connections.

The loading of selected function addresses into the BASIC I/O AD is explained after the description of analog/digital separator, baud rates, and protocol handshake type.

Analog/Digital Separator

Each BASIC I/O AD will require an analog/digital separator to be set. This identifies which modules are analog and which are digital. This is necessary so the system can properly direct each instruction to the appropriate module.

The analog/digital separator is teh character following the in  the sequential display. It should be set equal to the HEX value of the lowest numbered module position containing a digital module (input or output). If this BASIC I/O AD contains only analog modules, set this value to G. Refer to the worksheet found here.

Baud Rates

Any one of the standard baud rates can be used for the serial network communications. The sequential display indicates the letter H followed by the baud rate, divided by 100. As shipped BASIC I/O ADs are setup for 9600 baud; the sequential display indicates H096.

Protocol Handshake Types

Two protocol handshake types are available, 2 Pass and 4 Pass.

2 Pass

The Host transmits an instruction to a BASIC I/O AD. If the message is correctly received (ie valid address, instruction type and correct checksum), the BASIC I/O AD executes the instruction and returns the letter A and a CR or, where data is to be returned, the letter A followed by the data followed by a two character checksum and ending with a CR.

4 Pass

The Host transmits an instruction to a BASIC I/O AD. If the message is correctly received (ie valid address, but not necessarily the correct instruction type nor checksum), the BASIC I/O AD returns an A followed by the echo of the instruction, and does not execute it. If the Host then transmits an E, the command is executed in the same manner as 2 Pass. If the Host transmits any other character to any unit on the network, the instruction is disregarded.

The sequential display indicates the letter P followed by 2 or 4. As shipped, BASIC I/O ADs are setup for 2 Pass; the sequential display indicates P2. The actual setting of the Handshake Protocol Type into the BASIC I/O AD is detailed beginning here.

Network Type Switch

The digit after the L in the Sequential Display represents how the network switch is set. Go here for further details.

Note: The seven segment display will not reflect a switch position change until power has been cycled to the unit.

Changing Setup Parameters via Push Button

During setup, the user may need to change the unit address, serial link baud rate and protocol pass type. The pushbutton located under the removable cover is used to change these parameters. The pushbutton causes the adjacent red LED to flash each time it is pushed. Any changed values are automatically saved in non-volatile EEPROM.

During the diagnostic test period following the application of power, the sequential display shows: GoGoGo= . Flashing the pushbutton LED once when the = appears places the unit in the setup mode. The value of each setup character can be changed, as they appear in sequence by pressing the pushbutton. The display will continue to cycle through the setup sequence until there is a full cycle with no changes. The BASIC I/O AD then stores all values in EEPROM for automatic use following each power cycle. If desired changes were not implemented correctly, line power can be recycled and teh setup via pushbutton procedure can be repeated as required.

Once the unit has been placed in the setup mode, as described above, the value of each setup character shown below, can be changed.

U O O O 8 H 0 9 6 P 2 -  Only the underlined digits may be changed.

The 2 digits after UO indicates the Master Unit Control address; initially set for address 00H - 00.

Note: in the address offset mode, only the Master unit address is set, the other addresses are automatically set 40H above each other. Find more information here.

The digit after the indicates the analog/digital separator.

The 3 digits after H show the baud rate (divided by 100); initially set for 9600 baud = 096.

The 1 digit after P signifies the handshake protocol type; initially set for 2 Pass - 2.

The display continues to cycle through this sequence until there is a full cycle with no changes. The BASIC I/O AD then stores all values in EEPROM for automatic use following the next power cycle.

The unit is now in the operational mode, and teh sequential display cycle becomes*:

U0 = 00
U1 = 40
U2 = 80

Address Setup Via Network - VARIABLE mode only

Each function address, including the Master Control address, of the BASIC I/O AD can be set individually by issuing as special instruction to the current Master Control address of that chassis. This "set Variable Address" instruction should be used with caution as it will change the unit addresses and save them in the EEPROM. Consult the BASIC I/O AD protocol manual for details.

In the event that the new addresses become lost, they will appear on the sequential display.

The Pushbutton method can always be used to return to the OFFSET mode.

Communication Verification

Most startup problems are related to the communications link. The left network traffic LED (marked RECV) blinks when there is serial data traffic being sent to this BASIC I/O AD from the Host computer. The LED merely indicates serial data. It does not indicate that this data is valid, nor at the proper baud rate. The right network traffic LED (marked TRANS) blinks each time this BASIC I/O AD  sends data to the Host computer.

Hardware Error Codes

When the BASIC I/O AD is initially turned on, it goes through internal self test. If anything is not correct, the appropriate error code will flash on the sequential display. Try recycling power. If that does not resolve the error condition please call duTec Technical Support at 800-248-1632.

End of BASIC I/O AD manual

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