Glossary
M
MAC address | media access control address. A |
| programmed into each network card or device when it is manufactured. |
mandatory | When an Advantys STB I/O module is configured to be mandatory, it must be |
module | present and healthy in the island configuration for the island to be operational. If a |
| mandatory module fails or is removed from its location on the island bus, the island |
| will go into a |
| You must use the Advantys configuration software to set this parameter. |
master/slave | The direction of control in a network that implements the master/slave model is |
model | always from the master to the slave devices. |
Modbus | Modbus is an application layer messaging protocol. Modbus provides client and |
| server communications between devices connected on different types of buses or |
| networks. Modbus offers many services specified by function codes. |
MOV | metal oxide varistor. A |
| dependant nonlinear resistance that drops markedly as the applied voltage is |
| increased. It is used to suppress transient voltage surges. |
MSB | most significant bit, most significant byte. The part of a number, address, or field that |
| is written as the leftmost single value in conventional hexadecimal or binary notation. |
|
|
N
N.C. contact | normally closed contact. A relay contact pair that is closed when the relay coil is de- |
| energized and open when the coil is energized. |
N.O. contact | normally open. contact. A relay contact pair that is open when the relay coil is de- |
| energized and closed when the coil is energized. |
NEMA | National Electrical Manufacturers Association. |
network cycle | The time that a master requires to complete a single scan of all of the configured I/ |
time | O modules on a network device; typically expressed in microseconds. |
890USE19600 April 2004 | 61 |