INM 5500 Rev 11
56
6 .7 .6
MTL5582/MTL5582B - Resistance Isolator
Single channel, to repeat RTD signals
The MTL5582 or MTL5582B connect to a 2-, 3-, or 4-wire resistance temperature device (RTD)
or other resistance located in a hazardous area, isolates it and repeats the resistance to a
monitoring system in the safe area. The module is intended typically (but not exclusively) for
use with Pt100 3-wire RTDs. Switches enable selection of 2-, 3-, or 4-wire RTD connection.
The MTL5582/ MTL5582B should be considered as an alternative, non-configurable MTL5575,
for use in RTD applications where a resistance input is preferred or needed instead of 4/20mA.
The design is notable for its ease of use and repeatability. The number of wires which can
be connected on the safe-area side of the unit is independent of the number of wires which
can be connected on the hazardous-area side. The module drives upscale in the case of open
circuit detection. The MTL5582B replaced the MTL5582 during 2016 to improve the response
characteristics of the safe area circuit.
Hazardous area
Safe area
Terminal
Function
1
RTD input –ve
3
RTD input +ve
4
3-wire RTD input –ve
5
4-wire RTD input +ve
9
RTD output –ve
10
RTD ve
11
RTD output –ve
12
RTD ve
13
Supply –ve
14
ve
PWR
MTL5582
OFF position
ON position
Sw 1
Sw 2
RTD type selection switches
Sw 1
Sw 2
2-wire
OFF
ON
3-wire
ON
ON
4-wire
ON
OFF
Warning
: Check polarity of terminals used for safe-area connections. Safe-area terminals
9, 10, 11 and 12 are unipolar so it is essential to select a positive terminal on the MTL5582/
MTL5582B for connection to the positive of the RTD input card.
Figure 6 .32:
Top label
for MTL5582/
MTL5582B
