National Instruments EIGHT CHANNEL SPST RELAY MODULE 用户手册
cFP-RLY-421
8
ni.com
In-Rush Current
The type of load and its in-rush current characteristics, together
with switching frequency, can cause contact welding. For loads
with in-rush current, measure the steady state current and in-rush
current to determine the proper relay. Some typical types of loads
and the in-rush current they create are summarized in the following
chart.
with switching frequency, can cause contact welding. For loads
with in-rush current, measure the steady state current and in-rush
current to determine the proper relay. Some typical types of loads
and the in-rush current they create are summarized in the following
chart.
Status Indicators
Figure 3 shows the status indicator LEDs on the cFP-RLY-421.
Figure 3. Status Indicators
After you insert the cFP-RLY-421 into a backplane and apply
power to the network module, the green POWER indicator lights
and the cFP-RLY-421 informs the network module of its presence.
When the network module recognizes the cFP-RLY-421, it sends
initial configuration information to the cFP-RLY-421. After the
cFP-RLY-421 receives this initial information, the green READY
indicator lights and the module is in normal operating mode.
power to the network module, the green POWER indicator lights
and the cFP-RLY-421 informs the network module of its presence.
When the network module recognizes the cFP-RLY-421, it sends
initial configuration information to the cFP-RLY-421. After the
cFP-RLY-421 receives this initial information, the green READY
indicator lights and the module is in normal operating mode.
In addition to the green POWER and READY indicators, each
channel has a numbered, green output state indicator that lights
when the channel is in the ON state.
channel has a numbered, green output state indicator that lights
when the channel is in the ON state.
Type of Load
In-Rush Current
Resistive load
Steady-state current
Solenoid load
10 to 20 times the steady-state current
Motor load
5 to 10 times the steady-state current
Incandescent lamp load
10 to 15 times the steady-state current
Mercury lamp load
Approximately 3 times the steady-state
current
current
Sodium vapor lamp load
1 to 3 times the steady-state current
Capacitive load
20 to 40 times the steady-state current
Transformer load
5 to 15 times the steady-state current
0
1
2
3
4
5
6
7
PO
WE
R
READ
Y