Verifying Analog Signals; Verifying The Modbus Signal - Emerson MRLDS-450 Installation And Operation Manual

4.1.2. Verifying Analog Signals

The MRLDS-450 gas detector features a single configurable analog output. During
normal operation, the analog output of the instrument is proportional to the detected
gas concentration and can be selected from the following:
• 1 to 5V (Default)
• 0 to 5V
• 2 to 10V
• 0 to 10V
• 4 to 20mA
The MRLDS-450 Gas Detector uses different voltage/current values to indicate
various modes of operation. In normal operation the relative gas concentration
output is indicated by the analog output level. Output level is proportional to the gas
level as shown in Table 4-2:
Gas Concentration
0%
50%
100%
Table 4-2 - Gas Concentration Levels
The instrument may also enter several special states, these are indicated by the
specific analog output levels indicated in Table 4-3:
Mode of Operation
Instrument Fault
Offline Mode/Maintenance
Drift below zero
Normal operation
Measuring range exceeded
Fault on analog interface
Table 4-3 - Analog Output Levels

4.1.3. Verifying the Modbus Signal

The MRLDS-450 Gas Detector provides a Modbus RTU digital interface. All status
messages and most parameters that can be accessed and/or configured through the
Bluetooth® interface can also be accessed and/or configured via RS485 for Modbus
RTU.
14 • MRLDS-450 Refrigerant Gas Detection I&O Manual
1-5V 0-5V
1V 0V
3V 2.5V
5V 5V
1-5V 0-5V
≤ 0.3V N/A
0.75V N/A
0.95V N/A
1-5V 0-5V
5.12V 5.12V
> 5.25V > 5.25V
2-10V 0-10V
2V 0V
6V 5V
10V 10V
2-10V 0-10V
≤ 0.6V N/A
1.5V N/A
1.9V N/A
2-10V 0-10V
10.25V 10.25V
> 10.5V > 10.5V
4-20mA
4mA
12mA
20mA
4-20mA
≤ 1.2mA
3mA
3.8mA
4-20mA
20.5mA
> 21mA
026-1316 Rev 0