Control Panel Solutions

This control panel measures the pH, ORP, and Temperature of a process. The various sensors are connected to the dual-channel model EMEC LDPHRH controller for pH and ORP. The set-points are controlled via internal relays and wired externally to chemical dosing pumps to control the pH and ORP of the process. The mA outputs for these values are to be wired to a DCS or SCADA system.

The temperature mA output of the controller is connected to a PR-4116 transmitter, which is used to control a heater via a high-power interposing relay. The set-point of the temperature can easily be set on the transmitter, and the system provides user-friendly readings and an interface for the control.

In this example, the RealTech Controls model ETX water hardness controller sends a mA signal signal representing the water hardness in CaCO3 (Calcium Carbonate) to a PR-4114 transmitter which converts the signal into grains per gallon, as required by the customer.

The reading now in GPG (grains per gallon) is sent to a PR-5714 panel meter display to display the reading on the front of the control panel. The ETX Controller has a standard 3 x Relay set-point / alarm outputs, a mA output representing the water hardness, and MODBUS RTU as standard.

An alternate display panel shows the same ETX water hardness controller on the front of a panel with 3 x red alarm lights connected to the set-point alarm relays inside the controller. All 3 x alarms have been activated for the purpose of presentation.

This plug-and-play design requires the customer to simply install the sensor in the water flow, and plug the power cord into a standard power outlet. The system has been pre-calibrated and set up to achieve the measurement of water hardness in grains per gallon on the front panel meter display, while the water hardness Calcium Carbonate value is displayed inside the panel on the ETX controller.

A customer desired to have a robust stainless steel enclosure to house a temperature controller to control 3 x separate temperature elements. A protective cover was used to protect the face of the temperature controller against water ingress and accidental knocks. The set-points for the different temperature settings are sent to 3 x interposing relays which provide a higher power capacity to control heaters, already existing at the customer’s site.

The temperature controller was pre-programmed based on the customer’s specifications, and this enabled ease of commissioning.

A temperature sensor (RTD) was custom-designed to be placed in the process, along with a coupling adapter to fit directly into the existing piping. 20 Feet of RTD extension cable was provided, to be pre-wired from the control box to the temperature sensor in the process.

For plug-and-play operation, the customer simply had to mount the stainless steel enclosure, wire the temperature sensor, and relays to his heating elements, and plug the power cord in.

This control panel was designed for a customer who specified the following:

• 15 x Temperature sensors connected to the panel
• Each temperature was to be displayed individually
• All the information from the sensors was to be sent via Ethernet to a SCADA system

Solution:

15 x PR-4114 transmitters with displays were incorporated to accommodate the temperature sensors. These transmitters incorporated MODBUS communication, to send the signals to a MODBUS to Ethernet converter, all pre-wired and pre-programmed for plug-and-play operation.

This panel incorporates a WIFI accessible remote alarm device, which can send SMS and E-mail alarms for programmable process parameters. The set points are easily configurable in the software provided. The setup for the remote alarm device was pre-programmed and ready to use, as per customer specifications.

The inputs to this system are mA signals from a water treatment controller, representing a Peracetic Acid concentration for sanitation, as well as temperature. Isolated re-transmission of these signals is required to be sent to a SCADA system for additional monitoring and control. The isolated re-transmission of these signals is accomplished by using PR-3108 signal slim-line signal isolators, which galvanically isolate the mA signals, to be sent safely to the SCADA system.

For plug-and-play ease of operation, the customer is required to simply wire a power cord to the power supply, and wire the mA inputs and outputs.