Smart GPIB to RS-422/RS-485 Serial Interface Board
● Provides GPIB and RS-232 data interfaces to RS-422 or RS-485 devices. Adds a GPIB interface and a RS-232 to RS-485 converter. ● Smart firmware passes GPIB data to serial device. Does not require escape sequences or a second GPIB address. ● Provides all IEEE-488.2 functions and the Status Reporting Structure. Easiest way to add IEEE-488.2 capability to any serial device. ● User setable IDN message and serial configuration. Easy setup with ICS utility programs customizes the 4808 for the end product. ● Three operational modes handles any kind of serial device. Can be a smart interface or act as the front end for an embedded controller. ● Mounts directly to host chassis's rear panel. Easy installation eliminates extra cables and reduces cost. ● Runs on 5 ~ 15 VDC. Uses available DC power.
The Model 4808 GPIB <-> Serial Interface is a small, low cost interface board that interfaces serial devices with RS-422 or RS-485 signals to the GPIB bus. The ICS GPIB-to-Serial Interface Board 4808 provides a smart IEEE-488.2 compliant, GPIB-to-serial interface and includes an RS-232 to RS-485 converter that also provides a serial communications path from the rear panel to the internal serial device. The ICS GPIB-to-Serial Interface Board 4808's GPIB-to-serial data path can be set for any standard baud rate up to 57.6 kbaud and for all of the common asynchronous data formats. All configuration settings are user setable and are saved in the 4808's flash memory. The ICS GPIB-to-Serial Interface Board 4808 is typically mounted to the rear panel of the host chassis so the connectors can protrude through the rear panel or inside the host chassis. An on-card regulator lets the 4808 run on regulated or unregulated DC power.
Typical applications are adding a GPIB interface to a sensor or instrument that has a serial interface or adding an IEEE-488.2 interface to an embedded computer board.
Bus drivers incorporate power up/down protection to prevent glitching the bus during power turn-on.
Address Capability
Primary addresses 0-30 set by GPIB bus command. Address displayed on LED indicators at power turn-on.
SRQ Generation
SRQs are generated per the IEEE-488.2 specification when the unit is not addressed to talk and an enabled bit in the ESR, Questionable or Conditional register becomes set.
Rear panel serial signals conform to EIA Specifications for RS-232 signals. J2 is a DTE type interface with DTR, CTR and RTS signals pulled to +V.
Signals
Txd, Rxd, Gnd
Baud Rates
300 to 57.6 Kbaud
Data Bits
7 or 8 bits
Parity
Odd, even or none
Stop Bits
1 or 2
Internal Serial Connector
Internal serial signals for connection to the serial device are 4-wire or 2-wire RS-485 signals capable of driving 32 RS-422/RS-485 loads. Rx Differential receiver includes a termination network to hold the signals in a mark state when they are not being driven. 4-wire or 2-wire signal selection set by on card jumpers. Signal transmitter can be set for full or half-duplex operation by a SCPI setup command. The baud rate and data character format settings are the same for both serial connectors. Signal receiver can be always enabled for full-duplex operation disabled when transmitting to block the transmit data from being echoed back.
RS-232 to RS-485 Conversion
Rear panel characters buffered and retransmitted after the EOM character is received if the GPIB path is not enabled. User sets EOM character with a SCPI setup comand. Any serial characters received from the internal serial device are always transmitted to the rear panel connector.
SCPI Commands
The 4808 conforms to the SCPI 1994.0 Specification and uses SCPI commands to set its configuration: The reserved SCPI Keywords are:
- SYSTem
- STATus
- CALibrate
- DIAGnostic
Construction
Four layer PCB. Connector shells are connected to chassis ground.
Controls and Indicators
Six on board LEDs show selftest diagnostics, GPIB address and status.
PWR
On when power applied
RDY
On when Selftest passed
MTA
On when talk address recognized
MLA
On when listen address recognized
SRQ
On when SRQ generated
ERR
On when ESR error bit set
Grootte
101.6 x 114.3 x 17.9mm (l x w x h)
Connectors and Headers
GPIB
24-pin IEEE-488 connector with metric lock studs.
Ext. Serial
9-pin DE shell male connec- tor with 4-40 lock studs.
Device
9-pin DE shell female
connector with 4-40 lock studs.
