AMX nxc manual Setting the Voltage Clamp Jumper +12V or Open, +12 V mode setting default

NXC-I/O10 Input/Output Control Card

In switch mode, the A terminals are connected to the NetLinx Controller's ground. Sources that require isolation from the Controller's ground should use voltage mode, and provide switched DC power for sensing as required.

Setting the Voltage Clamp Jumper (+12V or Open)

Set the V- Clamp jumper (J31) to +12 V (default) to clamp any voltage connected to I/O ports 1-10 to 12 V.

Set to Open for connections that will draw more than 12 V.

Remember, the +12 V and OPEN settings are only enabled when the I/O ports are set to SW mode. The V-Clamp jumper settings are described below:

+12 V mode setting (default)

Use the default setting for all loads that require less than 12 V.

Open mode setting

When this jumper is set to Open, and an I/O port is used as an output, the I/O port is rated at 85 mA @ 28 VDC.

When this jumper is Open, it is the technician's responsibility to clamp the external source relay anytime the voltage exceeds 12 V. The source relay should always be clamped if the voltage exceeds 12 V. Contact the relay manufacturer to determine the size of the diode in the source relay.

NetLinx Cardframe, Control Cards, and NetModules - Operation Reference Guide 13