Emerson 54e pH/ORP Section Wiring, General, Power Input Wiring, Analog Output Wiring

MODEL 54e pH/ORP	SECTION 3.0
	WIRING

SECTION 3.0

WIRING

3.1 GENERAL

WARNING

All electrical installation must conform to the National Electrical Code, all state and local codes, and all plant codes and standards for electrical equipment. All electrical installations must be supervised by a qualified and respon- sible plant electrician.

NOTE

Wire only the analog and alarm outputs required for your application. Be sure to read the warning at the beginning of Section 2.0.

The Model 54e pH/ORP has five access holes in the bot- tom of the instrument housing which accept ½-in. strain relief connectors or conduit fittings. Be sure to seal any unused access holes. As you face the front of the unit, the rear openings are for input power, and alarm relay signals. The opening on the front left is for sensor wiring only (DC). The front right is for analog output wiring.

NOTE

For best EMI/RFI protection, the output cable should be shielded and enclosed in an earth grounded, rigid, metal conduit. Connect the output cable's outer shield to the earth ground connection on TB2 (Figure 3-1)

3.2 POWER INPUT WIRING

Figure 3-1 depicts the wiring detail for the Model 54e pH/ORP. Code -01: connect AC power to TB3, termi- nals 1 and 2 for 115 VAC (terminals 2 and 3 for 230 VAC). Code -02: connect DC power to TB3 terminals 1 and 2. Connect earth ground to the nearby ground lug. A good earth ground is essential for proper operation of the controller. Be sure to provide a means of discon- necting the main power to the controller.

CAUTION

Do not apply power to the controller until all electrical connections are made.

WARNING

Electrical connections to this equipment must be made in accordance with the cur- rent National and Local Electrical Codes in effect for the installation location.

3.3 ANALOG OUTPUT WIRING

The analog output wiring consists of two 4-20 mA sig- nals: output one from terminals 4 and 5, output 2 from 1 and 2 on TB2, as shown in Figure 3-1. These signals can be used for chart recorder, computer monitoring, or PID control output. The analog outputs can be pro- grammed for 4-20 mA or for 0-20 mA, direct or reverse acting. Current output 1 includes superimposed HART (code -09 only).

3.4 ALARM RELAY OUTPUT WIRING

The controller has 3 "dry" alarm relay contacts which are normally open. Alarm 1 is across terminals 4 and 5 on TB3. This alarm is typically used to control the pump in a chemical feed system. Alarm 2 across terminals 6 and 7 on TB3 is usually used to operate a light or horn as a means of alerting the chemical process operator when pH/ORP is outside the control range. Alarm 3 is across terminals 8 and 9 on TB3. All 3 of these alarms may be activated on pH/ORP or temperature. They can also be used to control other pumps or valves provided they are programmed to do so. Refer to Section 5.0 to set up these functions.

All three alarm contacts on the Model 54e pH/ORP are rated for a maximum of 3 A (1.5A, 230 VAC, inductive load). If your associated pump or valve exceeds this, use a separate contact or relay rated for the external device.

To use a contact output to control a pump, valve, or light, the contact must be wired into a circuit together with a source of power for the device to be controlled. The power can be jumpered from the main power into the controller and the circuit can be wired as shown on the wiring diagrams, Figure 3-1.

PREAMPLIFIER SELECTION

The pH sensor signal requires a preamplifier at some point in the measuring circuit. The preamp can be in- side the sensor, in the junction box, or in the controller. To allow for these options, the Model 54e pH/ORP has a jumper selectable preamp mounted on the CPU cir- cuit board (Figure 3-3). The jumper is placed in the "analyzer" position when there is no preamp in the sen- sor (or junction box). Generally, this jumper is in the "sensor" position.

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