37
200
190
200
190
200
200
200
190
190
190
ON
OFF
Figure 3.3
Normal Process Alarm
Figure 3.3
Normal Process Alarm
Process proceeds
Process proceeds
200
190
200
190
200
200
200
190
190
190
ON
Figure 3.4
Latching Process Alarm
Figure 3.4
Latching Process Alarm
SP2 = 200
AL.HY = 10.0
AL.MD = LTCH
AL.FN = PV.H.A
SP2 = 200
AL.HY = 10.0
AL.MD = LTCH
AL.FN = PV.H.A
Process proceeds
Process proceeds
3-7 RS -485 Communication
3-7 RS -485 Communication
Using a PC for data communication is the most economic way.
The signal is transmitted and received through the PC
communication Port (generally RS-232). Since a standard PC can't
support RS-485 port, a network adaptor (such as SNA10A, SNA10B)
has to be used to convert RS-485 to RS-232 for a PC if RS-485 is
required for the data communication. Many RS-485 units (up to
247 units) can be connected to one RS-232, that is a PC with 4
comm ports can communicate with 988 units.
Examples:
UM L91-Rev 8
