B&B Electronics I-7011 Benutzerhandbuch

63

I-7011, I-7018 User Manual

Rev:B1.0

Some analog input modules, like I-7011, equip with the

high/low alarm function. When the alarm function is enabled, the

digital output DO0 is the low alarm indicator, DO1 is the high alarm

indicator, and the digital output command for changing digital out-

puts DO0, DO1 is ignored. The alarm function is to compare the

analog input value with given high alarm value and low alarm value.

And there are two alarm types as follows :

z

Momentary alarm : the alarm status is cleared while the

analog input is not over the alarm value.

If Analog Input Value > High Alarm, DO1(High alarm) is on,

else DO1 is off.

If Analog Input Value < Low Alarm, DO0(Low alarm) is on,

else DO0 is off.

z

Latch Alarm : the alarm is cleared only the user send com-

mand to clear.

If Analog Input Value > High Alarm, DO1(High alarm) is on,

else if Analog Input Value < Low Alarm, DO0(Low alarm) is

on.

When two wires composed of dissimilar metal are joined at

one end and heated, the open circuit voltage is a function of the

junction temperature and the composition of the two metals. All

dissimilar metals exhibit this effect. The voltage is called “Seebeck

voltage”. For small changes in temperature the Seebeck voltage is

linearly proportional to temperature.