Discrete I/O Specifications
Input On/Off Delay
AKA Response Time. Specifies the max time duration required by an input module's circuitry to recognized that a field devise has switched on or switched off.
Points per module
Defines the number of field inputs or outputs that can be connected to a single module. Low end has 8-16 bits. High density modules have 32-64 bits
Nominal Input Voltage
Discrete: Specifies the magnitude (5V, 24V, etc) and type (AC or DC) of user-supplied voltage that a module is designed to accept. Can operate without damage
Electrical Isolation
I/O module circuitry is electrically isolated to protect low-level internal circuitry of the PLC from high voltages that can be encountered from field device connections.
Inrush Current
Momentary surge of current that an AC or DC output circuit encounters when energizing inductive, capacitive, or filament loads.
Short Circuit Protection
Provided for AC and DC output modules y either fuses or some other current limiting circuitry.
Input Threshold Voltages
Specifies 2 values: minimum On-state voltage which is the minimum voltage at which logic 1 is recognized as absolutely On Maximum OFF-state voltage which is voltage at which logic 0 is recognized as absolutely off.
Leakage Current
Specifies the amount of current still conducting through an output circuit even after the output has turned off. Normally less than 5 milliamperes
Nominal Current Per Input
Specifies the minimum input current that the discrete devices must be capable of driving to operate the input circuit. Protects against detecting noise or leakage currents as valid signals.
Output Current
Specify the max current that single output and module as a whole can safely carry under load (at rated voltage).
Backplane Current Draw
This value indicates the amount of current the module requires from the backplane
Output Voltage
This value specifies the magnitude and type Voltage and AC or DC. Designed to operate within a range of plus or minus 10% of nominal output voltage rating.
Ambient Temperature Rating
Value specifies what the max temperature of the air surrounding the I/O modules should be for best operating conditions.