MSA Ultima User Manual

Typical Wiring of the Ultima Gas Monitor
• Two-wire 4 to 20 mA Ultima Monitors operate in the current
mode (FIGURE 1-17)
• Three-wire Ultima Monitors operate in the current source,
frequency, or multiplex frequency mode, depending on your
model. For 4 to 20 mA current source output, see FIGURE
1-18. For multiplex and frequency output models see FIGURE
1-19.
Table 1-6. Cable Length and Wire Size (Power Supply 24 VDC) (Toxic
Gas or Oxygen) Sensor, 4-20 mA Signal Output (Three Wire Sensor)
In all installations twisted three-conductor, instrument quality cable is required.
In applications where interferences from RFI or EMI or other noise sources exist,
shielded cable is recommended.
WIRE SIZE
MAXIMUM CABLE LENGTH IN
FEET
MAXIMUM LOAD RESISTANCE
22 AWG 12,000 600 Ohms
Table 1-7. Cable Length and Wire Size IR Combustible Gas Sensor,
4-20 mA Signal Output (Three Wire Sensor)
In all installations twisted, three-conductor, instrument quality cable is required.
In applications where interferences from RFI or EMI or other noise sources exist,
shielded cable is recommended.
WIRE
SIZE
MAXIMUM CABLE
LENGTH IN FEET
@ 24 VDC
MAXIMUM
LOAD
RESISTANCE
MAXIMUM CABLE
LENGTH IN FEET
@ 12 VDC
MAXIMUM
LOAD
RESISTANCE
22 AWG 2,000
600 Ohms
100
250 Ohms
18 AWG 5,500 800
16 AWG 8,000 1,100
12 AWG 16,000 2,800
Figure 1-17.
Two-Wire Monitor Operation
Chapter 1, Set-up
1-15

MSA Ultima Specifications

General

Brand	MSA
Model	Ultima
Category	Monitor
Language	English