Installation
5.4 Installing the Electronics Housing
The distance between the electronics housing and a computer (via RS485 cable) can be up to 1200 m (4000 feet). This allows ample distance from the harsh environment where the sensing head is mounted to a control room or pulpit where the computer is located.
For reliable performance it is recommended that the power supply be no more than 60 m (200 feet) away!
Following you can see installation examples shown with two representative cable types. A 4‐wire cable is used to wire the 24 VDC power supply and one output of the electronics housing. A coated 12‐wire cable is used to wire all inputs and outputs of the electronics housing.
Sometimes in cable both sets of twisted‐pair wires have drain wires inside their insulation. These drain wires must be assembled and connected to the terminal labeled SHIELD (bare). Also connect the earth ground to the SHIELD (bare) terminal. The following figure shows how to configure the drain wires of both 4‐ and 12‐wire cables before connecting to the sensor and RS485/RS232 converter.
Attach to SHIELD | Twist braided shield and two drain wires from |
in electronics housing | the two twisted pairs together |
To electronics housing | e.g. |
to power supply, | |
| to RS232/485 converter, |
| other inputs/outputs |
|
|
Attach to SHIELD | Earth Ground |
in electronics housing |
|
To electronics housing | e.g. |
to power supply, | |
| 0/4 – 20 mA current output |
| |
| Earth Ground |
| Figure 14: Configuring the Sensor Cable |
The complete wiring must have only one common earth ground point!
Cables can be run to the electronics enclosure through conduit or fastened using the a compression fitting. Once you run the cable into the enclosure, attach the color‐coded bare wires to the terminals. Use the following figure (or diagram on underside of lid) as a wiring guide. Note that the terminal blocks in the electronics enclosure can be “popped” out for easy wire connections.
Marathon Series FA/FR | 19 |
