Glossary
POWERCELL™ control unit
Box of the ISIS system which connects to the loads (outputs) and receives commands from the MASTERCELL. This box switches the loads. The POWERCELL is also where the fuses are located in the system.
MASTERCELL™ input unit
The control center of the ISIS intelligent multiplexed system that switches (inputs) are connected to. The MASTERCELL input unit contains all of the ISIS programming and gives commands to the POWERCELL control unit to activate outputs. The MASTERCELL unit is also where the inSIGHT and inLINK modules are connected to the system.
inSIGHT™ Diagnostic Module
Optional LCD Diagnostic screen attached to the ISIS MASTERCELL input unit.
inLINK™ Radio Control Module
Optional Radio Frequency module. Allows for keyless entry as well as most other remote control functions desired.
inMOTION™ Power Module Control
A specialized type of POWERCELL control unit that is specifically designed to operate various types of fractional horsepower DC motors. Coming Soon. Contact Us for more information.
CAN Cable
Cable which controls the communication between the MASTERCELL and POWERCELL unit(s).
J1939
Protocol which dictates communication and diagnosis among vehicle components. Often used in heavy duty markets such as off road truck and bus, the ISIS system’s CAN network is compliant with J1939.
Heart Beat
Blue diode light near the middle of the POWERCELL control unit which enables the user to determine functionality of CAN connection between the POWERCELL unit and MASTERCELL. A quickly blinking Heart Beat means that there is a fault in the connection. A slowly blinking light signifies a working connection.
RF Indicator
Light on the MASTERCELL input unit which blinks if the inLINK module is installed in the system and properly connected. .
Train Button
Button on the MASTERCELL input unit to pair RF remote and ISIS system.
COM Light
MASTERCELL input unit heartbeat. Behaves the same as the “Heartbeat” of the POWERCELL
Home Button
When using the inSIGHT diagnostic module, this button brings the user back to the main MASTERCELL screen.
Scroll up/down buttons
Located and labeled on the POWERCELL control unit when the inSIGHT module is installed. Allow the user to move between messaging screens on the inSIGHT module.
Select button
Functions as the enter key on the MASTERCELL input unit when the inSIGHT module is installed.
CAN Hi / Lo Lights
Show health of the CAN connection.
Serial number
Specific identification number assigned to each ISIS unit. The Serial Number can be found on the label of the MASTERCELL input unit.
MASTERCELL Input Unit Programming header
7 pin interface found on MASTERCEL unit used for the transfer of information between a computer and the ISIS. If doing home programming, the Programming Module attaches here.
Multiplexing
The process of combining multiple data streams into one. The ISIS system uses multiplexing to minimize the amount of wires needed as well as the complication inherent in wiring by transmitting all input and output commands through one CAN cable.
MOSFET
The semiconductor used in the POWERCELL control unit to switch on different outputs when there is a command from the MASTERCELL input unit to do so. This replaces the function of a relay for greater functionality.
Inputs
The switches connected to the MASTERCELL input unit. The switch inputs the signal into the MASTERCELL unit which transfers it to the POWERCELL control unit outputs. To initiate an input, the wire needs to be pulled to ground.
Outputs
The devices connected to the POWERCELL control unit. The switch inputs the signal into the MASTERCELL input unit which transfers it to the POWERCELL unit outputs and applies the node personality.
Solid State
Circuits which do not contain relays or moving parts.
B+
Positive terminal of a car battery
Crimp Terminals
Metal contacts connected to the end of a wire. The contacts are sized and shaped to mate with another terminal or a screw.
MEGA® Fuse
Fuses between the battery of the car and ISIS POWERCELL control unit which protect the power cables from damage due to over current conditions.
MINI® Fuse
Industry standard Low Current Distribution fuses used to protect each of the output nodes on the POWERCELL control unit.
POWERCELL Control Unit Connector Cable
The cables that connect the outputs to the POWERCELL unit. There are two for every POWERCELL unit. Each output wire is 14-AWG TXL wire and is rated for 30 amps.
MASTERCELL Input Unit Connector Cable
The cable from the MASTERCELL input unit to the inputs (switches).
Battery Connector Cable
The cable between the power cell and the battery via the MEGA® fuse kit. Typical installations will have two power input cables.
Load
A component in a circuit that converts electricity into light, heat, or mechanical motion. Loads are the devices connected to the POWERCELL control unit.
Inductive loads
Load which uses a magnetic field. Inductive loads are generated by devices such as solenoids and motors that have moving parts. Inductive loads cause voltage spikes which need to be protected against using various circuit protection devices.
Resistive Load
Load which converts current into other forms of energy such as heat.
PWM (Pulse Width Modulation)
As related to the ISIS multiplexed electrical system, is the reduction of an output current to a set ratio by pulsing output current to reach a desired level.
One-to-Many
One input on the MASTERCELL input unit controls multiple outputs on the POWERCELL control unit.
Many-to-One
Many inputs on the MASTERCELL input unit control 1 output on the POWERCELL control unit
One-to-One
A single input on the MASTERCELL input unit controls a single output on the POWERCELL control unit
Many-to-Many
Many inputs on a MASTERCELL input unit controls many outputs on a POWERCELL control unit.
KEELOQ™ Code
The encryption of the radio frequency module that makes it virtually unbreakable.
CAN Terminator
The plug that goes into the open CAN connector socket on the last POWERCELL control unit in a chain. The resistor balances the impedance of the CAN network to ensure high-reliability data transmission.
Programming Module
Device which is used to program the MASTERCELL input unit. The programming module can be plugged into the programming header to program the ISIS.
Cell Address
The hardware defined address that physically identifies a device within the ISIS architecture. Typically each POWERCELL™ or MASTERCELL™ unit has a unique hardware address. Under very special circumstances, POWERCELL control units can exist at the same hardware address. The Littelfuse application-engineering department must approve this type of usage and supply specifically configured devices for this type of application.
Dry Contacts
This term defines a set of electrical contacts that have no voltage from any outside source applied to them. Although not ideal, one side of the contacts can be attached to vehicle chassis ground.
NOTE: The ISIS MASTERCELL input unit provides special “electrically quiet” grounds that are essentially the same as chassis ground, but are not subject to current spikes form the actuation of loads in the vehicle. It is strongly recommended that these provided grounds are used as the common side of all switches or sensors used as inputs to the ISIS system.
Input Node
This term defines a point on an ISIS MASTERCELL input unit that has been designed to take in information from a mechanical switch, sensor or electronic input device. Input nodes can be supplied with ON/OFF state information from the following devices:
- 'Dry' electrical contacts on any Mechanical Switch
- 'Dry' electrical contacts on any sensor or relay
- Open collector bipolar transistor with the emitter terminal connected to ground and no additional resistance in the emitter circuit.
- Open drain mosfet transistor with the source terminal connected to ground with no additional resistance in the source circuit
There are 48 digital and 2 analog input nodes on a MASTERCELL input unit. The 2 analog inputs are designed to take in information from a 0-5 Volt sensor (linear, log etc.) or a 0-5 Volt ratiometric voltage source like a potentiometer set up as a voltage divider.
NOTE: The maximum input voltage on the 2 analog inputs (inputs 49 & 50 on the MASTERCELL unit) is 0-5 Volts DC
Output Node
This term describes a point on an ISIS POWRCELL control unit that is designed to source electrical current to an electrical load. Each output node is created using state-of-the-art automotive grade power MOSFETs. Each output node is rated at a continuous output current of 25 DC Amps from 0-42 Volts without damage to the device. There are 10 output nodes on each POWERCELL control unit.
NOTE: Proportional outputs are possible on the MOSFET output nodes using PWM methods.
NODE PAIR
A set (2 to 10) of nodes on a POWERCELL control unit that cooperate in producing the correct output states for a specific node personality or function.
PERSONALITY NAME
This is the name assigned to the specific personality within the ISIS system
OUTPUT FOLLOWS STATE OF INPUT DEVICE
This indicates if the personality type follows the state of the switch controlling it; meaning if the switch is ON, the output node will produce the function. If the switch is OFF, the output node will stop producing the function
PERSONALITY MODIFIERS
These are special control words that can modify the basic action of the personality and are as follows (not all personalities can be used with all modifiers).
SOFT START
This modifier will change the characteristics of how the output node is started. For the first 500 milliseconds of the turn-on-cycle the output will be 50% Pulse Width Modulated to allow the load to come “on-line” without large current spikes in the vehicle or mechanical abuse to the filament in an expensive halogen bulb or damage to the brushes in BDC (Brushed Direct Current) motor. Using soft start on your headlights can double the life of the bulb and extend the life of the brushes in a D.C. motor
SWITCH DEBOUNCE TIME
This is the time that a mechanical switch is allowed to “bounce” internally before it’s state is read by ISIS for subsequent processing. All mechanical switches “bounce”. Almost any mechanical switch can be correctly read using a 10 millisecond debounce window. For special needs this value can be custom programmed for your system from 0 milliseconds to over 1 second. The 0 milliseconds option is used if you have electronic “bounce-less” inputs to your ISIS system. By reducing this number to 0, the overall system performance can be increased to manage over 50 state changes/input/second.
TYPICAL INPUT SWITCH TYPE
This defines the typical type of switch that would be commonly used in conjunction with the personality being described. The conventions in calling out a switch of a specific type are as follows:
SPST – This is the most common type of switch, also called an ON-OFF switch. The –SP- means that is has one set of electrical POLES, contacts, and –ST- means that the switch only has (2) active positions, ON and OFF. A “Toggle Switch” is a common form of a SPST switch
SPST-MOMENTARY – This switch is identical to the SPST switch, except that if the switch is put in the ON position it will automatically return to the OFF position. This is also called a momentary switch. Whenever you see “( )” around a switch description it means THAT position is momentary. An example would be an ON-OFF-(ON) switch, also called a SPDT, Single Pole Double Throw Switch. The ON position of the switch will remain in place until manually turned OFF. The (ON) position of the switch is spring-loaded and will return to the OFF position as soon as the handle is released
DPDT – This is also called an ON-ON switch with 2 independent sets of poles with a common center position. This switch has to independent set of electrical poles inside the switch that can control 2 independent circuits. The single switch actuator mechanically ties the 2 independent poles together
SPDT – This is also called an ON-ON switch. This type of switch usually has 3 outer terminals, each position of the switch actuator controls a common center terminal and 2 independent outer terminals. The common terminal is why it is called –SP- or Single Pole
ON-OFF-ON, (ON)-OFF-ON, (ON)-OFF-(ON) – All of these switches have a single OFF position in the middle of the switch actuation positions and a 2 independent sets of contacts with a single common side. A good rule to remember if you are not sure which position of the switch handle turns on which circuit is that the handle is always in the opposite position of the active switch poles. As mentioned above the various uses of “( )” indicate momentary operation
AS DEFINED ON A STANDARD SYSTEM
This tells you where the personality is found on a standard off-the-shelf ISIS System. Almost any combination is possible. Contact Littelfuse Application Support if you have specific questions about a custom configuration
