Panel Mount 4-20mA Controller in 96 x 96 Din Spec.

4-20mA Controller BC7635 Introduction

The BC7635 is our 4-20mA controller and is a member of our series 7635 analytical instruments. The 7635 series are housed in 96 x 96 Din standard enclosures which are only 95mm deep and are designed for mounting in panels or in a surface mounted enclosure.

The BC7635 takes a 4-20mA input from a compatible sensor and will provide power to loop powered devices.  The range of the connected 4-20mA connected device is displayed initially as the actual current output for commissioning and testing, and can be scaled using the onscreen menu.

As well as providing power to loop powered instruments - the BC7635 can take a powered input from a device with a 4-20mA device, such as a 4-20mA output signal from another 7635 or 7335 instrument device such as a P7635 or a P7335.

The ranges available are from 0-100.0% of the measured range or from -1999 to + 9999 in engineering units.

The decimal point positioning is user selectable with the following decimalisation options available:-

• XXXX
• XXX.X
• XX.XX
• X.XXX

Powered from a switch mode power supply 86 / 264 VAC, the BC7635 controller enables a 4-20mA control signal to be displayed using the LCD (Liquid Crystal Display), as well as control functionality.

4-20mA Controller BC7635 Control Functions

The BC7635 has a 2 x High/Low selectable set-points with an associated control relay.  The control relays are SPST rated for 220 V 5 amp resistive loads with adjustable delay timers and hysteresis.

In addition to the control relays the BC7635 includes an alarm relay and a 4-20mA output.  The 4-20mA output corresponds to the input 4-20mA signal and is isolated into 600Ω.

The versatility of the microprocessor accompanied by the user friendly software, allows the programming of the functions, routine checks and calibration to easily be accomplished even by untrained operators.  Installation of the 7635 series of instruments is intended to be into a control panel or in the optional surface mounting enclosure.

The rear of the case is fitted with plug-in connector blocks for ease of installation and maintenance.

BC7635 4-20mA Scaling

The input 4-20mA control signal can be scaled across a desired range, which makes it ideal for use in devices such as our Hydrostatic Level Sensors, where the 4-20mA is fixed at the point of ordering.

With a hydrostatic level sensor being used for water, the factory set range of 0 - 5 metres, where 0 metres means the tank is empty and the output signal is 4 mA, and when at 5 metres the tank is full and the output is 20mA, we can still use this level sensor on a tank with a depth of only 4 metres. When the level is at 4 metres our output signal is 16.8 mA - we can scale this in the BC7635 as being 100% full.

We can then use the set-points and control relays to automate a number of processes based on the tank level from 0-100%. 

4-20mA Controller BC7635 Features & Benefits 

The BC7635 is a really useful instrument if you're working with 4-20mA control signals.

The controller provides power to loop powered instruments, which when used with our LMK2 connecting cable, means that the signal can be connected up to 3 km away.  There are only 2 wires to connect, as the 4-20mA signal is transmitted over the same wires that power the device.

Alternatively the BC7635 can take a signal from a powered output such as one from the other instruments in our 7635 or 7335 range.

The incoming 4-20mA can be scaled in the BC7635, either as a percentage or in engineering units with a range from -1999 to + 9999 with the decimal point positioned as required on the 4 digit LCD.

The 4-20mA signal can also be transmitted from within the BC7635 to another device such as a PLC, Building Management System or Data Logger.  As the 4-20mA current signal is isolated into 600Ω, this makes the BC7635 an excellent gateway device with control functionality, without having the PLC's programmed for single tasks.

With 2 x control relays with High/Low selectable set-points and an alarm relay, the BC7635 is ideal for use as a stand alone surface mounted 4-20mA controller or as a panel mounted controller ideal for system integrators to use in their panels.

There are a huge number of compatible devices including from our own range of pH transmitters, Redox Transmitters, Conductivity Sensors, Dissolved Oxygen Transmitters, Turbidity Sensors and Level Measurement devices.