1771-SPI

The 1771-SPI PLC 5 SPI Protocol Interface Module by Allen-Bradley is a Network master device which coordinates the flow of data between a PLC-5 processor and the slave devices connected to the network and it stores configured information corresponding to each device connected on the network, returns configuration status to the PLC 5 processors, and returns status data from devices connected to the network to the host PLC 5 processor. The 1771-SPI is fitted into any 1771 I/O chassis slot and it draws a backplane current of 1.3A at 5V DC. It interfaces electronically through the RS-485 multi-drop serial port using a Field Wiring Arm Connector and it can support a maximum of 32 connected devices on the SPI link. The module comes with a 1771-WA Field Wiring Arm with a wiring arm screw torque of 7 x 9 inches-pounds. The 1771-SPI coordinates via the RS-485 multi-drop configuration with a communication speed of 1200-19200 bits per second (with 1200 bits per second required and 9600 common) and it uses the asynchronous, half duplex, IEEE floating point numbers, and Block Data Transfer protocol format. The module has 128+ possible Logical Device Addresses and uses an SPI protocol specified command set. The module is keyed to the Chassis via a connection between pins 12 and 14, 16 and 18 of the top connector and the connecting band. The 1771-SPI has a tested and factory-designated temperature range between 0 and 60 0C at 5-95% non-condensing relative humidity and a non-operational temperature range between -40 and 85 0C.