6. Operations and Functions
6-3. External output operation
- 40 -
Example of Gas Concentration and External Output
4 - 20 mA
(Maintenance output:
2.5 mA setting)
<Communication Specifications>
Power-line
communication
system
The gas detector is used in a local network formed with a multi-display unit
(RM-70NT) as the base unit. For more information, see the operating manual of the
multi-display unit.
Ethernet
The gas detector offers functions that work in liaison with external software using a
standard network protocol. For details, see the separate manual for communication
function.
Web function (HTTP), mail send function (SMTP), and time synchronization
function (SNTP)
Use a Web browser of an upper-unit PC to view and change setting values and
perform calibration and test on a graphical user interface.
SMTP, when receiving a gas alarm or fault alarm from an external mail server, can
send a notification mail to a registered address.
SNTP, receiving time information from a time server, can correct the clock at
regular intervals.
Modbus slave function (Modbus/TCP)
Works as a Modbus slave and feeds back a setting value in response to a read
request or changes a setting value in response to a write request.
PLC linkage function (FINS
・
MC)
Sends a setting value to PLC to provide information to be processed by PLC in a
ladder program. Reading from PLC is also available to change a setting value or
perform calibration and test.
2.5 mA
4mA
20mA
22mA
Full scale
Gas concentration
External output
0
Zero suppression
Detection mode
Maintenance mode
CAUTION
<Analog Transmission (4 - 20 mA)>
The 4 - 20 mA output is already adjusted. In case of over scale, an output will not exceed 22 mA.
Output during inhibit or initial clear is based on 4 - 20 mA output setting in the maintenance mode.
Be careful for a possible lower output which drops as low as 2.5 mA during initial clear when OSU
(L alarm) is used. In particular, this occurs when the gas detector is started or the specification is
changed. Understand how the gas detector functions, and take actions, if necessary, so that the
receiver side cannot get false alarms (e.g. making an inhibit status).
