6821 Programmable dual-channel transmitter0 pages

Nokeval

sales@nokeval.com
www.nokeval.com

Yrittäjäkatu 12
FI-37100 Nokia

Tel. 358-3-3424 800
Fax. 358-3-3422 066

6821 Programmable dual-channel transmitter
• 2 analog inputs, 0/4..20 mA or 0..5/10V, mV, Pt100, thermocouples
• 2 analog outputs 0/4..20 mA or 0..5/10V
• 2 alarm relays
• Mathematical and conditional operations using easy logic language (ELo)
• Serial communication RS-485
• Modbus RTU and Nokeval SCL protocols
• Power supply 90..240 VAC or 24 VDC
• Conguration using MekuWin PC program or using front panel buttons
6821 is a rail-mounted two-channel measurement unit for temperature sensors and other
electrical inputs. The unit has two analog outputs or alternatively one analog and one serial
output.
The serial output can accept Nokeval SCL and Modbus RTU commands. Up to four logical
alarms can control two common alarm relays. The inputs are galvanically isolated from the
outputs and the supply voltage, but not from each other.
Mathematical and conditional operations may be realized with a simple programming language. There is a four-digit display and four pushbuttons, that can be used to monitor the readings and to change the settings. The settings can also be edited from a personal computer
using the RS-485 serial connection.
Schematic drawing of transmitter 6821
Inputs:
• Pt100, Pt1000, Ni100,
KTY83, Cu10
• Thermocouples:
B, C, D, E, G, J, K, L, N, R, S, T
• mV inputs: ±55 mV, ±100 mV
• 0..20 mA, 4..20 mA, ±20 mA
0..1 V, ±1 V, 0..10 V, ±10 V
• Resistance measurement:
0..400, 0..4 kΩ, 0..40 kΩ

Analog input x2

Galvanic
isolation

Analog output x2

Registers

Input 1

In1

Output 1

Input 2

In2

Output 2
Display

Built-in functions
Avg
Min
Max
Diff

Avg
Min
Max
Diff

123.4

User program

Writing your own functions
Measurement results and alarm states are written into registers. Users can easily write
simple programs to modify registers F1-F12
using Nokeval’s ELo language and MekuWin
conguration program. Any register can be used
in the programs and used as an output source.

@18+=@1
@2>0?2

Serial interface
F1
F2
F3
F12

Alarm comparator x4
+
-

Flow sensor pressure compensation example

Mass ow rate

OR function

Alm1
Alm2
Alm3
Alm4

Relay output x2

Serial connection
Nokeval SCL
Modbus RTU
2 alarm relays:
max. 240 VAC, 2A
Four separate logical
alarms can be set

Programming examples using ELo language (MekuWin)
Input channels 1 and 2 correspond to registers @1 and @2,
any register can be used as an output source.
Channels multiplied
@18=@1*@2 // The result is placed in register 18 (F1)

Channel 1 Channel 2

Pressure
4..20 mA

Mass ow rate can be easily calculated using 6821 transmitter. Use channel
1 to measure the ow, 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.

Peak hold
@1<@18?2
@18=@1

// If current rdg is smaller, skip the next line
// Store the new peak in register 18 (F1)

Clock
@18+=@0

Volume flow
4..20 mA

Outputs:
0..20 mA
4..20 mA
0..5 V
10 V

// Register 18 (F1) will indicate seconds

Mass ow rate
@19=@1*@2
@18=@19*0.00112

// Channels multiplied, result in register 19 (F2)
// Register 18 = (Ch1 x Ch2) x 1.12/1000