SIEMENS LIM-1 Loop Isolator Module Instruction Manual
- June 9, 2024
- SIEMENS
Table of Contents
SIEMENS LIM-1 Loop Isolator Module
OPERATION
The Model LIM-1 Loop Isolator module from Siemens Industry, Inc., isolates short circuits on MXL and FireFinder-XLS intelligent device loops. By placing devices between LIM-1s during installation, a short in the wiring within that group is disconnected from the rest of the loop. The remainder of the devices continues to operate. The LIM-1 operates in both Class A and Class B circuits. A yellow LED flashes when a device detects a short circuit. The LIM-1 then isolates that part of the loop. When the short is removed, the LIM-1 automatically restores the loop to normal operation. The LIM-1 does not have a loop address and therefore does not require address programming nor does it reduce the loop capacity below 60 (MXL) or 252 (XLS) devices.
ELECTRICAL RATINGS
| Active 5VDC Module Current | 0mA |
|---|---|
| Active 24VDC Module Current | 760uA |
| Standby 24VDC Module Current | 760uA |
INSTALLATION
Remove all system power before installation, first the battery and then the AC. Refer to Figure 1 for the location and number of the screw terminals on the LIM-1. The LIM-1 has two input terminals, two output terminals, and an earth ground as listed below:
Terminal Number/Description
- 1 Loop + IN
- 2 Loop – IN
- 3 Loop + OUT
- 4 Loop – OUT
- 5 Earth Ground
MECHANICAL INSTALLATION
(See Figure 2)
- Use a standard 3 1/2-inch deep, double gang electrical switch box or a 4-inch square electrical box that is 2 1/8 inches deep.
- Connect the field wiring. Press the LIM-1 into the box and fasten the module plate to the box.
- Cover the module front plate with the plate supplied and fasten it with the screws supplied.
The LIM-1 may be used in two circuit configurations.
Class B (See Figure 3)
In Class B wiring each LIM-1 isolates a branch on the circuit. Note that a
short on the main branch causes the entire loop to fail. To prevent this,
mount the LIM-1s at the MXL or FireFinder-XLS enclosure and run each branch
independently.
NOTES for Figure 3:
- All wiring must comply with national and local codes.
- In order to provide adequate protection, it is recommended that you do not install more than 20 devices on a single LIM-1.
- The minimum wire gauge is 18 AWG.
- The total wire resistance (both wires) between LIM-1s cannot exceed 10 ohms.
- Do not install more than 12 LIM-1s per loop.
- All circuits are supervised.
- Refer to the MXL/MXLV Manual, P/N 315-092036, the MLC Installation Instructions, Document ID A6V10328217, or the DLC Installation Instructions, Document ID A6V10239107, for the list of compatible devices.
- All terminals are power limited.
Class A Single Loop (See Figure 4)
In Class A wiring the LIM-1s are wired in series with the loop wiring. This
results in a single continuous loop. If any group in the loop has a short,
that group is lost and a Class A circuit failure results. The MXL or
FireFinder-XLS displays communication errors for the devices and a Class A
failure for the loop itself.
NOTES for Figure 4:
- All wiring must comply with national and local codes.
- In order to provide adequate protection, it is recommended that you do not install more than 20 devices on a single LIM-1.
- The minimum wire gauge is 18 AWG.
- The total wire resistance (both wires) between LIM-1s cannot exceed 10 ohms.
- Do not install more than 12 LIM-1s per loop.
- All circuits are supervised.
- Refer to the MXL/MXLV Manual, P/N 315-092036, the MLC Installation Instructions, Document ID A6V10328217, or the DLC Installation Instructions, Document ID A6V10239107, for the list of compatible devices.
- All terminals are power limited.
Contact Information
Siemens Industry, Inc. Building Technologies Division Florham Park, NJ.
P/N 315-049552-6.
Siemens Canada Limited
Building Technologies Division 2 Kenview Boulevard Brampton, Ontario L6T 5E4
Canada.