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Nokeval 6821 User Manual

2 channel transmitter
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User manual
2017-01-23
Firmware V1.0-1.6
6821
2 channel transmitter
1

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Summary of Contents for Nokeval 6821

  • Page 1 User manual 2017-01-23 Firmware V1.0-1.6 6821 2 channel transmitter...

  • Page 2: Table Of Contents

    The input channels are individual and can be used for different signals. The unit has two analog outputs or alternatively one analog and one serial output. The serial output accepts Nokeval SCL and Modbus RTU commands. Up to four logical alarms can control two alarm relays. The inputs are galvanically isolated from the outputs and the supply voltage, but not from each other.

  • Page 3: General

    Serial communications. Power supply Outputs 4 3 2 1 4 3 2 1 4 3 2 1 4 3 2 1 6821 Input 1 1 2 3 4 Input 2 1 2 3 4 1 2 3 4 TC, mV, V,...
  • Page 4 Jumpers To access the jumpers, use a small screwdriver to click the four locks (see photo). Then pull the top and bottom parts of the case apart. The power supply must be disconnected to avoid electric shocks. The picture shows the jumper locations and the default setup. The jumpers labeled “Free”...
  • Page 5 Registers Analog input x2 = writes into a register = can be configured to read any register Scaling Lowpass filter Display Registers 123.4 Built-in functions Analog output x2 Diff Diff Ext1 User program Serial interface Ext2 @18+=@1 @2>0?2 OR function Alarm comparator x4 Alm1 Alm2...
  • Page 6 Average of the readings, (In1+In2)/2 Smaller of the readings In1, In2 Greater of the readings Diff Difference In1-In2 Isens RTD excitation current in mA, normally about 0.25 Internal cold junction temperature in °C Cycle The measured time to get all the channels, in seconds Out1 Analog output 1 signal in mA or V Out2...

  • Page 7: Power Supply

    Power supply The transmitter 6821 is available for two supply voltage ranges, that are nominally called “24VDC” and “230VAC”. 6821-24VDC This model accepts supply voltage of 20 to 28 V DC or AC. The supply is connected in connector A terminals 1 and 2.

  • Page 8: Front Panel

     Monitor state – displaying the readings and other Enter variable data. Exit Nokeval 6800 Series Normal state After power-up, the front panel is in the normal state, displaying the input 1 reading (unless otherwise set). The ”channel” being displayed can be selected using the ^v keys. While changing the channel, the channel name is displayed until the key is released.
  • Page 9 A password is set as follows: push ^ to select Set (means password will be used), then push > to enter the new password. Cod.0 is shown. The password is a sequence of six key presses using all the four keys. Enter the same password twice;...
  • Page 10 Src1…Src4 (Display) Display submenu is used to define which readings (or registers) you want to see on the display. Up to four registers can be selected in Src1..Src4 (the registers are described on page 5). If you do not need all the four registers, set the rest to Off.
  • Page 11 Menu tree The complete configuration menu is shown here to aid navigating. The menus are explained in the relevant chapters:  General and Display: page 9.  Inputs: page 15.  Math: page 21.  Outputs: page 17.  Alarms and Relays: page 20. ...

  • Page 12: Inputs

    4 3 2 1 In addition, jumper settings inside the case might need adjusting. The factory 6821 setting of the jumpers is suitable for all input signals except the mA signal.  In1 = mA: If closed, an internal 50 ohm shunt resistor is connected...
  • Page 13 Close the mA jumper on that channel. Transmitter supply This transmitter can provide a 15 V 50 mA supply for an external transmitter. This voltage is output at connector H terminal 1 (+) and terminal 4 (ground). To switch on the voltage supply, the jumper “In2 pin1 = +15V”...
  • Page 14 This is the easiest way to connect, and the only that will allow several volts between the negative lines of the inputs. External linking If the input sensors are galvanically isolated from each other, then it Diff. amp is recommended to tie them both to the input circuitry ground. Connect a piece of wire between the terminals 3 and 4.
  • Page 15 This transmitter calculates always four inter-channel readings: the average, the smaller, the greater, and the difference of the inputs. Fault detection If the transmitter finds the sensor faulty, the corresponding In1 or In2 register will be set to a NaN (not-a- number) value to indicate an exception.
  • Page 16  400ohm, 4000ohm, and 40000ohm: Resistance inputs. The resistor is connected in three-wire or four- wire connection. The reading is in ohms.  Pt, Ni, Cu, and KTY83: Resistance thermometers (RTD's). The nominal resistance is set in R0 (see below). The reading is in Celsius or Fahrenheits.

  • Page 17: Analog Outputs

    Free Out1 = mA 4 3 2 1 4 3 2 1 Out1 = V Out2 = mA Out2 = V 6821 Out2 = 485 1 2 3 4 Free Free 1 2 3 4 1 2 3 4 The two analog outputs are provided in the connector B.
  • Page 18 Range Analog output range mA or V. The jumpers inside have to be set correspondingly. Rdg1, Out1, Rdg2, and Out2 Output scaling. The reading Rdg1 corresponds to the output signal Out1 (in mA or V), and Rdg2 to Out2. These have not to be the end points, since the transmitter is able to extrapolate. Example: Reading 0-6 (bar) is wanted to give output of 4-20 mA.

  • Page 19: Alarms And Relays

    G terminals 1 and 2, and the second relay in terminals 3 and 4. These have no internal connection elsewhere: they are 6821 “potential free”. The relays can be used to control a 230 VAC line voltage. If one relay is...
  • Page 20 Alarm settings Conf Alarms Alm1 General Alm1 Type There are four identical logical alarms, one in each Display Alm2 Alm1…Alm4 submenu. The first alarm controls the Inputs Alm3 Level register Alm1 and so on. The relays following these Math Alm4 Hyst alarms are set up in the Rel1 and Rel2 submenus.

  • Page 21: Elo Program

    ELo program If the capabilities offered by the transmitter are not enough, they can be Conf General extended by writing a custom program inside the transmitter. With the ELo Display programming language, it is possible to do simple calculation, conditional Inputs execution, and timing.
  • Page 22 dest=src1+src2 Sums src1 and src2 value and places the result in dest register. E.g. F1=In1+10 will add register In1 contents to constant value 10 and place the result in register F1. dest=src1-src2 Subtracts. dest=src1*src2 Multiplies. dest=src1/src2 Divides. dest=srcSQ Calculates a square root. E.g. F1=In1SQ dest=src1&src2 Bitwise AND.
  • Page 23 Peak hold (result in F1) In1<F1?2 //If current rdg is smaller, skip the next line F1=In1 //Store the new peak Prevent negative (result in F1) F1=In1 //Take a copy F1>=0?2 //If not negative, skip the next line F1=0 //Was negative, have a zero Clock F1+=Intv //Register F1 will indicate seconds...

  • Page 24: Serial Communications

    Display Protocol Inputs Serial protocol: Serial Math Protocol Outputs  SCL: Nokeval SCL protocol, slave. Address Alarms  Modbus: Modbus RTU protocol, slave. Baud Relays Address Serial Serial bus address. Valid choices for SCL are 0-123 and for Modbus 1- 247.
  • Page 25 All the settings of the transmitter can be accessed from a PC. A free software “Mekuwin” is used, available at the Nokeval WWW site. (Alternatively, with the Modbus protocol, the settings can be read and changed using the standard Holding register functions.) Of course, an RS-485 connection to the PC is needed, for example a Nokeval DCS770 USB-RS-485 converter.
  • Page 26 MN xxxxx Commands used by the Mekuwin configuration software.
  • Page 27 The maximum Modbus frame length is 150 bytes. This sets the limit to the number of registers accessed with commands 3, 4, and 16. The command 17 will return 0x11 <byte count> 0x00 0xFF, followed with ”6821 V1.6 A123456”, for example.
  • Page 28 30..31 1018 FLOAT Signed 32..33 1019 FLOAT Signed 34..35 1020 FLOAT Signed 36..37 1021 FLOAT Signed 38..39 1022 FLOAT Signed 40..41 1023 FLOAT Signed 42..43 1024 FLOAT Signed 44..45 1025 FLOAT Signed 46..47 1026 FLOAT Signed 48..49 1027 FLOAT Signed 50..51 1028 FLOAT...
  • Page 29 45..46 Conf\Inputs\In2\Sca2 FLOAT Signed 47..206 Conf\Math\ELo STRINGZ Len=320 Conf\Outputs\Out1\Src ENUM See table E1 Conf\Outputs\Out1\Range ENUM See table E5 209..210 Conf\Outputs\Out1\Rdg1 FLOAT Signed 211..212 Conf\Outputs\Out1\Out1 FLOAT Signed 213..214 Conf\Outputs\Out1\Rdg2 FLOAT Signed 215..216 Conf\Outputs\Out1\Out2 FLOAT Signed Conf\Outputs\Out2\Src ENUM See table E1 Conf\Outputs\Out2\Range ENUM See table E5 219..220 Conf\Outputs\Out2\Rdg1...
  • Page 30 Enum explanations Table E1 Keys Table E2 Value Value Speed Slow Normal Fast Super Table E5 Diff Table E3 Isens Value Range Value Unit Cycle °C Out1 °F Out2 Table E6 Table E4 Alm1 Alm2 Value Type Value Sensor Alm3 Alm4 55mV Rel1...

  • Page 31: Specifications

    Specifications Thermal drift 0.02°C / °C (ref 25°C) Environment Accuracy 0.05% rdg + 0.5°C + lin.error + thermal drift Storage temp -30…+70 °C Oper. temperature -10...+60 °C Humidity Non-condensing Ranges ±55 and ±100 mV Altitude <2000 m from sea level Accuracy 0.1% rdg + 0.01 mV Pollution degree...
  • Page 32 0.005 V Thermal drift 2 mV/°C EMC immunity Serial communications EN 61326 Connection RS-485 EMC emissions Protocols Nokeval SCL slave, Modbus EN 61326 class B RTU slave Baud rates 1200, 2400, 4800, 9600, Electrical safety 19200, 38400, 57600 EN 61010-1 Bits...

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