Allen-Bradley 1771-IBD DC (10-30V) Input Module
The 1771-IBD DC (10-30V) Input Module accepts DC voltage levels on 16 inputs and converts these signals to logic levels. The minimum input current rating is 4mA at 10V DC and 12mA at 30V DC. The minimum on state voltage is 10V DC. The Maximum off state current is 2.4mA, and the maximum off state voltage is 6V DC. The input impedance of the module is 2.5K ohms maximum per channel.
1771-IBD DC (10-30V) Input Module Strapping
The 1771-IBD DC (10-30V) Input Module has a fault mode which may be configured. This fault mode is independent of the last state switch on the Universal I/O Chassis backplane, and will place the inputs of the module in the corresponding state if a fault is detected. To configure the fault mode jumper, locate the jumper at the top edge of the module circuit board as it appears in figure 11.1. Configure the 2 position jumper on the middle and LS pin of the three pin header for last state fault mode. Configure the two position jumper on the middle and RESET pin of the three pin header for reset fault mode.
1771-IBD DC (10-30V) Input Module Installation
The Allen-Bradley 1771-IBD may be installed in any Allen-Bradley Universal I/O Chassis, 1771-A1B, 1771-A2B, 1771-A3B, or 1771-A4B. Before Installation, calculate the power requirements of the modules currently in the chassis. Add to that 250mA @ 5V DC, the current required by the 1771-IBD. Check to be sure that this combined current requirement does not exceed the current driving ability of the chassis power supply.
Module Location in the I/O Chassis
The 1771-IBD may be placed in any slot of the I/O chassis with the exception of of the extreme left slot. This slot is occupied by the Remote I/O Adapter Module. It is suggested that analog input modules and low voltage DC modules be placed away from AC modules or high voltage DC modules to minimize electrical noise interference.
The 1771-IBD has an additional restriction. EPICS software reads and writes the Allen-Bradly chassis in Two-slot addressing mode. A module group is considered to contain two Allen-Bradly slots. The first module group address is located at slot 0 and 1. The second is slot 2 and 3 and so on. When using a 16-bit input module in a two-slot addressing mode, the input module must always be inserted into an even number slot (left-hand side of the module group). A complementary output module (8-bit or 16-bit module) may be inserted into an odd number slot (right-hand side of the module group) completing the module group. If no complementary module is used then that slot must remain empty.
The Allen Bradley Universal I/O chassis have the ability to limit the slot access to certain modules by the implementation of a keying system. Modules are slotted in two places at the edge of the circuit board. The position of the keying bands on the backplane connector of the I/O chassis must correspond to these slots. To key a slot for use by the 1771-IQ Contact Output only, place the keying bands between 10 and 12 and between 16 and 18 on the I/O chassis backplane connector.
Before a module is inserted into the Universal I/O Chassis, be sure that the power to the chassis is shut off. This can be done without shutting off the IOC that the Universal I/O Chassis is connected to, and without removing the subnet communication link. To insert the module, place it in the plastic tracks on the top and bottom of the Universal I/O Chassis. Slide the module into the Universal I/O Chassis until the module comes in contact with the backplane connector. Do not force the module in, instead apply firm and even pressure on the module to seat it properly on the backplane connector. Snap the chassis latch over the top of the module and connect the wiring arm to the module. The Universal I/O Chassis should begin communicating with the host IOC when power is reapplied, no rebooting of the IOC will have to be done.
1771-IBD DC (10-30V) Input Module Wiring Connection
Connecting field wiring to the 1771-IBD is accomplished through the use of the wiring arm. Signals should be connected to the screw terminals of the wiring arm, as detailed in figure 11.2, and the wiring arm should be connected to the front tab connector on the 1771-IBD. Note that on the wiring arm the inputs are labeled 00 - 17 (octal). When shielded cable is used and grounding of the shield is desired, it is recommended that the connection be made at one of the I/O chassis mounting bolts. To prevent ground loops only one end of the cable shield should be grounded.
1771-IBD DC (10-30V) Input Module Use
The front panel on the 1771-IBD contains 17 LED indicators. The top green LED indicator labeled ACTIVE indicates the module is connected to +5 volts and operating normally. The next 16 red LED indicators, labeled 00 through 17 (octal), will indicate if an input is true. The indicator will be illuminated if the input is true (there is voltage at the terminal) and out if the input is false (there is no voltage at the terminal).