Allen-Bradley 1771-OBD DC (10-60V) Output Module

1771-OBD DC (10-60V) Output Module

The 1771-IBD DC (10-60V) Output Module produces a DC voltage level on any combination of 16 outputs. The voltage level output is determined by a user supplied power supply. The maximum output current is 2A per output, not to exceed 8A per module.

1771-OBD DC (10-60V) Output Module Strapping

The 1771-OBD DC (10-60V) Output 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 outputs of the module in the corresponding state if a fault is detected. To configure the fault mode jumper, locate the jumper at the bottom edge of the module circuit board as it appears in figure 12.1. 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-OBD DC (10-60V) Output Module Installation

Power Requirements

The Allen-Bradley 1771-OBD 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 400mA @ 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-OBD 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-OBD 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 output module in a two-slot addressing mode, the output module must always be inserted into an odd number slot (right-hand side of the module group). A complementary input module (8-bit or 16-bit module) may be inserted into an even number (left-hand side of the module group) slot completing the module group. If no complementary module is used then that slot must remain empty.

Module Keying

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 22 and 24 on the I/O chassis backplane connector.

Module Insertion

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-OBD DC (10-60V) Output Module Wiring Connection

Connecting field wiring to the 1771-OBD 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-OBD. Note that on the wiring arm the outputs 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-OBD DC (10-60V) Output Module Use

The front panel on the 1771-OBD contains 18 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 output is true. The indicator will be illuminated if the output is true (there is voltage at the terminal) and out if the output is false (there is no voltage at the terminal). There is also a red LED FUSE indicator. This will be illuminated if the on-board output protection fuse is blown.