Instruction Manual

Instruction Manual

D102748X012

Installation

October 2014

Electrical Connections

WARNING

Select wiring and/or cable glands that are rated for the environment of use (such as hazardous area, ingress protection and

temperature). Failure to use properly rated wiring and/or cable glands can result in personal injury or property damage

from fire or explosion.

Wiring connections must be in accordance with local, regional, and national codes for any given hazardous area approval.

Failure to follow the local, regional, and national codes could result in personal injury or property damage from fire or

explosion.

Proper electrical installation is necessary to prevent errors due to electrical noise. A resistance between 230 and 1100

ohms must be present in the loop for communication with a Field Communicator. Refer to figure 2‐9 for current loop

connections.

Figure 2‐9. Connecting a Field Communicator to the Digital Level Controller Loop

230   R

 1100 

POWER

SUPPLY

Signal loop may be grounded at

any point or left ungrounded.

A Field Communicator

may be connected at any

termination point in the signal

loop. Signal loop must have

between 250 and 1100 ohms

load for communication.

Reference meter

for calibration

or monitoring

operation. May

be a voltmeter

across 250 ohm

resistor or a

current meter.

E0363

NOTE:

1 THIS REPRESENTS THE TOTAL SERIES LOOP RESISTANCE.

−

Power Supply

To communicate with the digital level controller, you need a 17.75 volt DC minimum power supply. The power

supplied to the transmitter terminals is determined by the available supply voltage minus the product of the total loop

resistance and the loop current. The available supply voltage should not drop below the lift‐off voltage. (The lift‐off

voltage is the minimum “available supply voltage” required for a given total loop resistance). Refer to figure 2‐10 to