Control Supply Voltage Powered Transmitters

Control supply voltage powered transmitters for various sensors, processes and frequencies. Inputs available in part of the selection. We deliver transmitters also set ready. Supply voltage 90..240VAC or 24 VDC.


The RTC685 is a single-channel DIN rail mounted industrial transmitter for temperature sensors and for signal conversion. A thermocouple, an RTD, or an analog process signal (mA or V) can be connected to the input. Various processing options are provided: filtering, table linearization, custom functions. An analog output (mA or V) is provided, along with an RS485 serial bus. The serial bus supports the Nokeval SCL and the Modbus RTU protocols. The device can be configured with a computer and a programming cable, or remotely over the RS485 bus. The programming cable is DCS772 combined with an adapter POL-3PIN.


The pulse converter 6420 is designed for pulse sensors whose input frequency needs to be converted into analog output 0/4..20 mA or 0..5/10 V. The converter has an exceptionally wide frequency range 0.0003 Hz..20 kHz, so that it is ideally suited to e.g. flow sensors providing very low pulse frequencies. Besides the current output the converter features one alarm level and a digital output. Making use of the alarm level the converter may function as a batch controller as well.


Signal converter 6740 accepts almost all common sensor inputs. It”s configured by PC. Transmitter front has configuration connector which connects adapter cable POL-RS232 to serial port of the PC. Menu based configuration program is easy to use. By hand held programmer 6790 yit”s easy to control or configurate the transmitter in field conditions.


6821 is a rail-mounted two-channel measurement unit for temperature sensors and other electrical inputs. If needed the device can use inputs of different types on its channels. The unit has two analog outputs or alternatively the second output can be serial RS485 output. The device has up to four logical alarms with two alarm relays. Power supply is 90…240 VAC or 24 VDC. There are four built-in inter-channel functions: average, difference, minimum, and maximum. With MekuWin configuration software and simple Nokeval ELo-language, programs can be written to make the device calculate more mathematical and conditional operations and even timed events.


6841 is a DIN rail mounted strain gauge / weighing transmitter. It is equipped with a small display and push buttons to allow configuration without a separate programming device. There is also two alarm relays, analog output, and RS-485 serial output with Nokeval SCL and Modbus protocols. The sensor can be connected using 6-wire measurement to eliminate wire resistance effect. Sensor excitation is about 10 V DC.


Multichannel transmitter RMD680 has been designed for applications where lots of inputs have to be measured and transferred economically either to PC or PLC. Transmitter has 16 input channels, which can be programmed individually for different sensors. Measurement rate is 12 channels per second. Measurements can be read either by serial interface RS-485 using Modbus RTU or Nokeval SCL protocol or with one analog output.


RMD681 is an 8 channel measurement unit for temperature sensors and process inputs. The unit has both one analog and serial outputs. The analog output can be selected among the input channels using digital inputs. Every channel has two alarm levels controlling two common alarm relays. The inputs are galvanically isolated from the outputs and the supply voltage, but not from each other. Configuration can be done also with serial RS485 bus.

2 wire transmitters 4-20 mA

External power supplied transmitters for various sensors, processes and frequencies. Outputs available in part of the selection. We deliver transmitters also set ready upon request. Supply voltage 90..240VAC or 24 VDC.



Transmitter 6720 is exceptionally versatile and accepts all most common sensor inputs. You can configurate it by PC via Cable POL-RS232. Transmitter front has configuration connector which connects adapter cable POLRS232 to serial port of the PC. Menu based configuration program is easy to use and together with low cost cable makes delivery economical even in case of one unit only. Galvanic isolation is specially important with thermocouples but potential differencies with other measuring circuits can be avoided also with process input signals and maintenance measurements.


The model 620S temperature transmitter is designed to meet the most exacting temperature measuring requirements. Three standard temperature ranges are available, 0-100, 0-150 and 0-200 ºC. For other ranges, see freely programmable model RTB231 and RTB232. Input:  Pt100 sensors, ranges according to order (not programmable) Output: 2-wire 4-20 mA


HTB230 is 2-wire transmitter with 4…20 mA output and Pt100-, Pt1000-, Ni100-, Cu10- and potentiometer, which is designed for use with Type B connection head. HTB230 is delivered with default settings for Pt100 3-wire 0…150°C range. The wide operating range of -40…85°C allows use in almost any industrial enviroment conditions. The transmitter is easy to install not only inside a connection head but also to DIN-rail (35 mm) by using separately ordered HTB230 DIN-rail bracket.


Air sensor for measuring room temperature. The measuring elemet is Pt100 sensor. Inside the case is installed a HTB230 transmitter with 2-wire 4-20 mA output. Input: Pt100 probe sensor Output: 2-wire 4-20 mA.

Signal Conventors

Serial Data Conventors

Transmitters with supply voltage for various sensor inputs, process inputs and frequencies. Output in some device models. We deliver transmitters also set up according your request. Voltage 90..240VAC or 24 VDC.



7470 is a serial-bus controlled analog output unit. It provides four mA or V outputs, that can be controlled via an RS232 or RS485 bus. As a slave, it supports Nokeval SCL, Modbus RTU, and Ascii protocols. Alternatively, it can function as a SCL Master querying other devices. Analog output ranges include 0…20mA, 4…20mA, 0…5V, and 0…10V. 7470 needs 24 VDC supply voltage. The analog outputs are not galvanically isolated from the power supply or each other. They share the common negative wire. However the serial bus is galvanically isolated.


DCS770 is used to add an RS-485 connection in a PC computer. It is connected in a USB port, and the drivers create a virtual COM port that can be used as an ordinary COM port. Even the baud rates and bit configuration can be changed in Windows port settings – these require no jumper settings. DCS770 can be used with a variety of protocols, including Nokeval SCL and Modbus ASCII and RTU. To aid troubleshooting, DCS770 is equipped with three indicator LEDs. It is small in size, and it has screw terminals eliminating the need to make solder joints on cables. Due to individual serial number on every device, these devices retain the COM port number if detached and replugged, even in a different USB port.


With DCS772 you can add a POL interface to your PC. POL interface is used to setup Nokeval devices supporting POL interface. DCS772 is connected to PCs USB port. Drivers of DCS772 will create a virtual serial port, which can be used as common serial port. Baud rates and amount of bits are selected in Windows Control Panel or directly from your application. DCS772 is used only for configuration. DCS772 fits directly to the products that have a 3.5 mm jack. If the device has a three-pin header, an adaptor POL-3PIN is also needed.

Signal Convertors & Galvanic Isolators

Signal Convertors have been designed to convert various measuring signals. The devices can separate the input and output galvanically while doing signal convertions simultaneously.



Nokeval has designed a very slim 9 mm 2-wire converter with galvanic isolation. Converter is powered by output 2-wire loop. It is specially suited to isolate analog inputs of programmable logics because those supply the power and wiring is simple. The idea of connecting power supply to output side eliminates typical problems of conventional isolators like small output load and high input side voltage drop. Three input types are available: 0..20 and 4..20 mA or 0..10V, output is always 4..20 mA. Output load is 700 Ω by 24 VDC power supply.


Signal converter 641 is designed to convert standard process input  and output signals. Current inputs 0/4…20 mA can be converted into voltage outputs, -10…10 V can be converted to 0…10 V, low mV inputs can be converted to standard outputs etc. Signal converter 641 accepts 2-wire transmitters without separate power supply. Potentiometer input as a standard. Galvanic isolation is made at the same time with the convertion. Galvanic isolation cuts the noise signals which may exist when using low voltage signals, f.ex. thermocouples.


Loop powered galvanic accuracy isolator 6570B is has a current loop input 4…20 mA. It works without auxiliary operating voltage by taking its own energy from the input current loop. Galvanically isolated active output 4…20 mA or 0…10 V.