Allen-Bradley 1771-IQ DC Selectable Input Module
The 1771-IQ DC (5-30V) Input module accepts DC voltage levels on all 8 inputs and converts these signals to logic levels. Each input circuit is individually selectable for current source (current flowing from the 1771-IQ to the DC input device) or current sink capability (current flowing from the DC input device to the 1771-IQ). This module may also be configured from either HIGH TRUE or LOW TRUE logic with an input delay of 1ms maximum or 12ms typical. For the HIGH TRUE setting TRUE is any voltage greater than 40% of the extern al supply voltage, and LOW is any voltage less than 20% of the external supply voltage. For the LOW TRUE setting, HIGH is any voltage less than 20% of the external supply voltage, and LOW is any voltage greater than 40% of the external supply voltage. The nominal input current per channel for an ON condition is 5mA for 5V DC, and 25mA for 30V DC. The external supply voltage power supply must be able to provide 100mA per module at 5V DC, and 350mA per module at 30V DC.
1771-IQ DC Selectable Input Module Strapping
Remove the module's left hand cover plate (the one without the labels). Observe the location of the configuration switches below, and note the location of the individual channels as illustrated in figure 9.1. Switch bank SW-1 is used to configure the input delay, and the true level of the logic. figure 9.1 contains sufficient information to describe these switch settings. Switch bank SW-2 and SW-3 are used to configure each input individually for either current sink or current source. For current sink set SW-2 to the ON position and SW-3 to the OFF position for the appropriate input signal (switch 1 corresponds to signal 0, and switch 8 corresponds to signal 7). For current source set SW-2 to the OFF position and SW-3 to the ON position for the appropriate input signal (switch 1 corresponds to signal 0, and switch 8 corresponds to signal 7). Note: setting an individual channel's SW-2 and SW-3 switch to either both on. or both off is an invalid setting.
1771-IQ DC Selectable Input Module Installation
The Allen-Bradley 1771-IQ Contact Output Module 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 150mA @ 5V DC, the current required by the 1771-IQ. 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-IQ may be place 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 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 6 and 8 and between 24 and 26 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-IQ DC Selectable Input Module Wiring Connection
Connecting field wiring to the 1771-IQ 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 9.2, and the wiring arm should be connected to the front tab connector on the 1771-IQ. 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-IQ DC Selectable Input Module Use
The front panel of the 1771-IQ contains eight red status indicators. Each of these indicators corresponds to a single circuit within the module. When the input to a specific circuit is TRUE (whether the module is selected for HIGH TRUE or LOW TRUE logic), its corresponding status indicator will illuminate. The top LED will indicate the status of signal 0, while the bottom LED will indicate the status of signal 7.