Understanding the C8 Board - Part 1

LifeSafety Power's FlexPower line of power systems is the industry's first and only fully-modular, listed power supply system.  This allows you to choose from a variety of power supplies and output boards and combine them in the best combination for the job at hand.  One of the most versatile components at your disposal is the C4 or C8 lock control board.  Don't let the "lock control" fool you, however - the C4 and C8 can do far more than just locks. 


The C4 and C8 come in four different variations.  The C4 and C8 provide 4 and 8 zones, respectively, of 3A fused outputs.  The C4P and C8P provide the same 4 and 8 zone counts but use 2.5A PTCs, rather than fuses, to provide Class 2 Power Limiting.  In this multi-part series of posts, we will refer mostly to the C8 board, but the C8P, C4, and C4P are all identical in operation.

What does the C8 do?

The C8 board provides eight outputs, each with its own input for control.  If you are familiar with the Altronix ACM8, then you are already familiar with this basic concept.  The inputs of the C8 are low current, protecting your high-cost access control panel's relays from the high currents and return EMF spikes from the locks.  Each output can be individually selected for voltage, lock type, input type, and whether or not to unlock the door on a Fire Alarm Input (FAI) activation.  Outputs can be wet or dry (NO or NC).

Input Power & FlexIO Connections

Like all FlexPower output boards, the C8 has a dual-buss power input, allowing use in either single or dual voltage power supplies.  When used in a dual voltage power supply, the C8 allows you to select either voltage on each individual output.  Note that the C8 MUST be supplied with constant power for proper operation.  Do not use the DC2 output of the FPO power supply to power the C8 board - the C8 controls each output for FAI on its own.


The first power supply should be connected to the B1 input of the C8.  As with all FlexPower output boards, the power connections can be made at either B1 terminal.  The BR connection serves as the DC common and must be connected to the BR terminal of the power supply.

If a second power supply is also being used, it should be connected to the B2 input of the C8.  The second power supply's BR terminal must also be connected to the other BR terminal of the C8 so that everything is common grounded together.

The FlexIO connectors supply FAI input and fault status to and from the C8 board.  Both FlexIO connectors are the same and either may be used interchangeably.  Simply plug one end of the white 2-pin FlexIO cable into the FPO power supply's FlexIO connector and the other end into the C8.

If there are other output boards already connected to the power supply, the C8 may be connected at the end of the chain, or inserted into the middle of the chain.  Make sure to match up the wire colors and B1/B2 connections to the other boards in the system.

Visual Indicators

The C4 and C8 boards have a green LED for every output indicating its status.  When the C8 is properly configured, a steady green LED indicates that the door is locked, and a flashing green indicates unlocked.  Notice we are speaking in terms of "locked" and "unlocked" rather than about the outputs being powered and unpowered.  This makes understanding and configuring the C8 easier, once you are accustomed to thinking this way - all LEDs function the same, whether the input is NO or NC, whether the output is connected to a maglock or door strike, whether FAI is active or not.

If any of the green LEDs are out, it indicates that there is a problem with the fuse (or PTC), jumper settings, or there is a missing power supply voltage.

The C4 and C8 also have a single yellow fault LED.  It will light whenever any of the green LEDs are out (blown fuse, incorrect jumper setting, or missing power supply voltage).  If there is a fault on your FPO power supply and the C8 also indicates a fault, correcting the C8 fault will likely clear the FPO fault unless multiple problems exist in the system.

Next Up..

This time we covered some of the very basics of the C8.  In the next part in this series, we will go even more in-depth on the inputs of the C8 board - including wiring, configuration, and other information. Until then, if you need any assistance our Technical Support department is always here to help.