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In English Suomeksi


programmable dual-channel transmitter




Typically in stock



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.


Writing your own functions

Measurement results and alarm states are written into registers. Users can easily write simple programs to modify registers F1-F12 (@18..29) using Nokeval’s ELo language and MekuWin configuration program. Any register can be used in the programs and as an output source.

How to write simple program?
The program consists of lines. Every line has one simple command. The command can change a register or cause a conditional jump inside the program. The program is entered in the configuration settings with Mekuwin.  Example: temperature input 1 controls output 1 together with input 2.

Flow sensor pressure compensation example
The mass flow rate can be easily calculated using the 6821 transmitter. Use channel 1 to mea­sure the flow, channel 2 to measure the pressure and write a small program using ELo language. For example, the program for the equation “Out1=(Ch1 x Ch2) x1.12/1000“ is found from programming examples.

Writing formula:

F2=In1*In2 // Channel 1 and 2 are multiplied, result in register F2
F1=F2*0.00112 // Register F1 = (Ch1 x Ch2) x 1.12/1000
Then the desired output is configured to follow the result, e.g. Outputs/Out1/Src = F1.


Load manuals (pdf)
Load datasheets (pdf)

Input details


Pt100, Pt1000, KTY83, thermocouples, mV, V, mA, Ohm

supply for transmitter

+15 V, 50 mA

input channels


measuring rate

both channels 0.25 s

Output details

output range

mA: 0...20 mA or smaller
V: 0...10 V or smaller

output loading

mA: 0...600 Ω

output channels




alarm relays


Connection details

connector model

2.5mm², detachable

bus interface


bus protocol

Nokeval SCL
Modbus RTU

baud rates

1200, 2400, 4800, 9600, 19200, 38400, 57600

Display details

display color


number of digits



7 segment LED

indicator lights

configuration state and alarms

digit size

7 mm

Power supply

power consumption

24 VDC: 200 mA
240 VAC: 5 W

supply voltage

230 VAC: 85-260 V AC/DC

General information


250 g


45 x 100 x 110 mm (WHD)


35 mm DIN rail

minimum ambient temperature


case material


maximum ambient temperature


Related products


USB to RS485 converter


Configuration program

2 x Input: thermocouples, Pt100, Pt1000, ±100 mV, 0/4-20 mA, 0-5/10V, potentiometer. 2 x Output: 4-20 mA, 0-10V, serial RS485/232, 2 alarm relays. Power supply: 90..240 VAC or 24 VDC.