GE IC697MDL653 Digital Input Module

Functions 

The 24 Volt DC Positive/Negative Input Module provides 32 input points in four isolated groups of eight points each. 

The input current–voltage characteristics meet IEC standard  (type 1) specifications. 

LED indicators that show the ON–OFF status of each point on the logic (PLC) side of the circuit are located at the top of the module. 

               Operation of the 24 Volt DC Positive/Negative Input Module 

Input Characteristics: This module has both positive and negative logic  characteristics – it sinks or sources current from the input device to the user common.  The input device is connected between the power bus and the module input as shown above. This module is compatible with a wide variety of input devices, such as: ▪ Pushbuttons, limit switches, selector switches; ▪ Electronic proximity switches, both 2 and 3–wire. In addition, inputs on this module may be directly driven by a compatible voltage output module. The input circuitry provides sufficient current to ensure reliable operation of the switching device.  Input current is typically 10mA in the ON state. An input in the OFF state can accept up to 2mA leakage current without turning on. 

Proximity Switch Compatibility:  3–wire proximity switches are easily applied, since they provide low voltage drop in the ON state and low leakage current in the OFF State. 2–wire proximity switches derive their power from the signal connections; thus both the ON state voltage and the OFF state leakage current are higher than for 3–wire devices.  This module is compatible with many such 2wire devices; however each device type must be carefully evaluated for compatibility in both the ON and OFF states. To determine compatibility with a specific proximity switch, find the ON state characteristics of the switch in the following diagram.  If that point falls to the left of the input load line, the ON state characteristics are compatible.  As an example, the ON state requirements of a compatible proximity switch of 3mA at 5 volts drop are shown below.  OFF state compatibility is assured if the proximity switch leakage is less than 3mA with a module input voltage of 5 volts or less. 

Input Filter Selection:4 I Load (mA) 6 8 10 This module can be configured to have either a 1 ms or 10 ms input filter.  Configuration is on a module, not per point basis; all points have the same filter time.  See the PLC Reference Manual for detailed information. 

Interrupt Input: If the CPU supports input interrupts,  input point A1 may be configured to cause an interrupt.  Configuration allows the CPU to be interrupted on either the rising or falling edge of the signal transition.  Interrupt response is not affected by input filter time selection.  Refer to the PLC Reference Manual for detailed information. 

Module Keying: Earlier versions of this module included a mechanical key to prevent inadvertently replacing a module with another of the wrong type.  The key latched onto the backplane center rail when the module was first installed, and remained on the backplane if the module was removed. A new module without this keying feature can be installed in a previously-keyed slot without removing the earlier keying. However, the key is easily removed by pushing it upward to unhook the latch while pulling it off the rail.