Nokeval FT20 User manual

Nokeval
FT20
User Manual

2
Contents
Document information...................................................................................................................................... 2
Introduction....................................................................................................................................................... 3
Trademarks........................................................................................................................................................ 3
Manufacturer .................................................................................................................................................... 3
Installing ............................................................................................................................................................ 4
Maintenance...................................................................................................................................................... 8
Firmware settings .............................................................................................................................................. 9
Operation......................................................................................................................................................... 14
SCL protocol..................................................................................................................................................... 15
Modbus protocol ............................................................................................................................................. 16
Nopsa commands ............................................................................................................................................ 19
Specifications................................................................................................................................................... 23
Document information
Device Scope: FT20
Device Versions: 1.1 to 1.2
Document Type: manual
Document ID: 2873
Document Version: 17
Document Date: 2.10.2012

3
Introduction
FT20 is a radio data receiver and repeater for Nokeval MTR, FTR and KMR series wireless transmitters.
Type FT20-RTC433-RECEIVER means the device is pre-set as receiver only. Type FT20-RTC433-REPEATER
means the device is pre-set as repeater and is supplied with a power supply.
FT20 receives and buffers the data packets that wireless transmitters have sent. It can also relay the data
packets so that large areas can be covered using only one receiver. It automatically recognizes the types of
the transmitters, so different kinds of transmitters can be used simultaneously. Transmitters can also have
different transmission intervals. FT20 uses license-free 433.92 MHz frequency band (ISM) so it can be freely
used, for example, almost in whole Europe.
FT20 is housed in a watertight (IP 66) and impact resistant plastic enclosure. The joint between the two
modules is sealed with two rubber O-rings. The receiver is connected to a computer using RS-485 bus and it
requires e.g. PromoLog data acquisition application that reads the data from the device.
Nokeval SCL or Modbus RTU protocol is used for data transmission between the receiver and the computer.
Multiple receivers can be connected in parallel to an RS-485 bus to increase the coverage area. FT20 has
one diagnostic LED and it requires 8..30 VDC power supply.
Trademarks
This device uses the FreeRTOS real-time operating system version 6.0.5. The source code of the RTOS is
available on request –contact [e-mail].
Manufacturer
Nokeval Oy
Yrittäjäkatu 12
FI-37100 Nokia
Finland
Tel [phone] (Mo-Fr 8:30-16:00 EET)
WWW http://www.nokeval.com/
email [email protected]om,
[email protected]m

4
Installing
Mounting
The best installation environment for a radio receiver is above a big grounded horizontal metal surface
surrounded by as few as possible vertical metal surfaces. Antenna is to be installed perpendicular to the
metal surface. The best range for the transmitter is achieved when there is a line-of-sight from the receiver
to the transmitter. Walls and objects between the transmitters attenuate the signal and thereby shorten
the range. On the other hand, metal surfaces cause reflections which might lengthen the range.
Placing the repeaters
The repeater must be placed in the coverage area of at least one receiver. For example, in the picture
below the whole warehouse is covered using two repeaters that are placed near both ends of the
warehouse. In this way the receiver that is placed in the center of the warehouse can receive transmissions
anywhere from the warehouse.
RS-485
Repeater Repeater Receiver
50..200 m
Coverage area
Warehouse

5
Using two repeaters
The picture below shows how two repeaters can be daisy chained.
RS-485
Repeater Repeater Receiver
50..200 m
Coverage area
Warehouse
The downside of daisy chaining is that now both repeaters relay also the data that they receive from the
other repeater. This increases radio traffic and therefore decreases the maximum allowed number of radio
transmitters in a coverage area. See the transmitter’s manual or example table on page 6 how the use of
repeaters affects the maximum number of transmitters.
Both repeaters can be placed in the coverage area of one receiver like in the example picture below.
RS-485
Receiver
Warehouse
Repeater
50..200 m
Coverage area Repeater

6
The maximum number of transmitters
The maximum number of radio transmitters in a coverage area is limited by radio standards. The use of
repeaters reduces the maximum number of transmitters because repeaters use the same frequency
channel as transmitters. The following example table shows the allowed maximum number of Nokeval
radio transmitters in a coverage area.
Transmission
Interval (s)
Receiver
Receiver and
1 repeater
Receiver and
1 repeater
Maximum number of transmitters
5
22
11
7
10
43
22
14
20
87
43*
29
30
130
65
43
40
174
87
58
50
217
109
72
60
261
130
87
70
304
152
101
80
348
174
116
90
391
196
130
120
522
261
174
240
1043
522
348
For example, if you have transmission interval of 20 seconds and one repeater, the maximum number of
transmitters is 43*.
Note: ID filter can be used to reduce the radio traffic caused by the repeaters. Using ID filter, only the
desired transmitter data packets is repeated (see the section "Firmware settings" sections Repeater/ID
filter and Channels/Repeater).
Enclosure
FT20 consists of a radio transceiver module (FT20-RTC433) and a processor/serial module (FT20-RS485).
Before use, please make sure that the modules are pushed together all the way so that the locking latches
snap into position.

7
Opening the case
Modules can be detached from each other by pressing the locking latches on the sides of the enclosure and
at the same time pulling the modules apart.
For receiver operation the serial module must be opened for RS485 and power
cables installation. Serial module can be opened by gently pushing a screwdriver
into the slot that holds the cover plate.
When the cover plate is removed, the circuit board can be pulled out of the
enclosure.
Connections
2
3
4
1
RS-485
Power
8...30 VDC
+ - D1 D0
POL
Jumpers
Diag. LED
Default RS485 settings
RS485 AC term.
Repeater Transmit.
LED
FT20 serial module has a 4-pin terminal block for power supply and RS-485 connection. Serial module
features also a round 3.5 mm POL programming connector jack found on many other Nokeval products as
well. FT20 radio module contains BNC type antenna connector.
Power supply
The supply voltage range is 8...30 VDC and is connected to terminals 1 (+) and 2 (-). Power demand is 50
mA. FT20 is protected against wrong polarity of the supply voltage.
RS-485 serial bus
RS-485 is used when the device operates as a receiver. RS-485 interface can easily be added to a computer
by using Nokeval DCS770 or DC771B USB - RS-485 converter or RCS770 USB/RS-232-RS-485 converter. If
you use DC771B converter, no external power supply needed (DC771B's power supply should be set to
10V). RS-485 bus is connected to terminals 3 (D1) and 4 (D0). The supply voltage's negative terminal 2 (-)
can also use as ground for RS-485.
The RS-485 bus consists of a bidirectional half-duplex twisted data pair and a common wire. The cable
should be shielded, the shield earthed at one point. The nominal impedance should be approx. 100-120 Ω.
The length of an RS-485 bus can be up to 1 km and it can be connected to 32 devices, more can be
connected via bus repeaters. If the bus is long (say more than 100 m), it is recommended to terminate the
first and last device on the bus (set the ”RS485 AC term” jumper to ”on” position).
The polarity of the data pair is important. Modbus specifications call the positive idling line D1, but it is also
commonly known as +, B, and A. Correspondingly the negative idling line is -, A, or B.
The bus needs one device that gives a small voltage between the data wires when no device is transmitting
on the bus. This is called biasing or fail-safing. The master device is usually the natural choice for biasing.

8
POL connector
The POL connector is convenient for configuring when the device operates as a repeater. This connector
can be used when the modules are disconnected from each other. Note that when the POL plug is
connected the RS-485 bus is disabled.
Two types of programming cables are available:
•POL-RS232 for the RS-232 port of the computer.
•DCS772 for the USB port of the computer (recommended).
Antenna
Antenna is connected to the transceiver modules’s BNC connector. Antenna is first pushed into the BNC
connector by aligning it with two guide posts after which it is turned 90 degrees clockwise. Antenna can be
removed by turning it counterclockwise after which the antenna can be pulled off.
Jumpers
FT20 has three jumpers in the serial module: ”RS485 AC term”RS-485 termination jumper, default serial
settings jumper and jumper which turns repeater on or off (if enabled in firmware settings).
If the device is the last device on the RS485 bus and the bus is long (say more than 100 m), it is
recommended to set the ”RS485 AC term” jumper to ”on” position. When this jumper is set, AC
termination is used which means that 1 nF capacitor and 110 ohm resistor are connected in series between
the bus wires.
Maintenance
Cleaning
The plastic parts can be cleaned with a soft cloth and soap water. The cloth must be damp but not wet.
Cleaning with isopropyl alcohol is also allowed.

9
Firmware settings
Repeater mode
User does not normally need to setup the device. By default, the device type FT20-RTC433-REPEATER is
setup as repeater (repeater jumper is on) and it repeats all the received data packets. In some special cases,
for example, when there is lot of transmitters, ID filtering may be needed.
Receiver mode
If you use PromoLog data acquisition software, then there is generally no need to configure the device. Just
check that the repeater jumper is off because the repeater mode is not needed and thus prevent the extra
radio traffic.
Mekuwin
MekuWin can be used to change settings on various Nokeval products. It has a unique feature: it loads the
structure and the contents of the configuration menu from the target device, so the same MekuWin
version can be used with past and forthcoming products. There is no need to update this software every
time a new product or product version is released. You can download Mekuwin from Nokevals web site for
free. Mekuwin has its own instruction manual.
It is also possible to change the configuration settings remotely by writing to the appropriate Modbus
Holding registers.
With a POL programming cable
The communications parameters for POL are always:
Protocol
SCL
Baud
9600
Parity
8N1
Address
0
Over the RS-485 serial bus
The Mekuwin communications parameters must match the selections made in the device (Serial menu).
Resetting RS-485 serial communication settings
In case RS-485 serial settings are for some reason not known, they can be temporarily set to defaults by the
“default RS485 settings” jumper (shown in the figure on page 7) when the device is powered up.
Default communication parameter settings:
Protocol
SCL
Baud
9600
Parity
8N1
Address
0

10
Serial
Protocol
Baud rate
Bits
Address
Configuration settings
The configuration settings are arranged as a hierarchical tree: The Conf menu has submenus, and these
contain settings and possibly more submenus, etc.
Menu of the FT20:
Conf
Serial
Channels
Repeater
Advanced Options
Advanced Options
Weak repeater filter
Compatibility mode
Repeater
Repeater
ID filter
Extra bytes
Max jumps
Replace with RSL
Ch1
ID
Value
Reading
Info
Repeater
Serial
Protocol
Baud rate
Bits
Address Channels
Timeout[min]
Count
Ch1
Ch2
Ch3
Ch4
Ch5
Ch6
Ch7
...
Ch100
Serial submenu
Serial communication settings.
Protocol
•SCL: Nokeval SCL protocol. Default.
•Modbus RTU: Modbus RTU protocol
Baud rate
Baud rate selection: 300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200, 230400.
Default 9600.
Bits
Bit selection: 8N1, 8N2, 8E1, 8O1.
Note! SCL protocol uses always 8N1 (this item does not appear when the protocol is SCL). Modbus RTU uses
commonly 8E1.
Address
Serial communications address selection. Since several devices can be attached to a bus, each device needs
to be configured to a different Address. Valid SCL-addresses are 0...123. Valid Modbus RTU-addresses are
1...247. Default 0.

11
Channels submenu
Up to 100 channels can be set up in the radio receiver. These channels can be set up to contain any data
received from the radio transmitters. The values of these channels can then be queried over the serial
interface. This menu contains settings for configuring these channels.
Timeout
The number of how many minutes have to pass since last reception
until it is determined that the device is not transmitting anymore
and its value is set to NaN (Not a Number). For example if Timeout
= 10 min then channel value is set to NaN when more than 10
minutes but less than 11 minutes have passed since last reception.
Count
Sets how many channels are used (0...100).
Ch1 ... Ch100
100 MTR series transmitters (for example MTR260 and FT10) can
be defined to act as certain channels. For example, when the device
receives ”MEA CH 1?” command it sends latest received data from the transmitter that has been assigned
to channel one. To assign a device to channel one, set the transmitter's ID to Ch1 ID value. Other channels
can be assigned in the same way.
ID
Identification (ID) number of the transmitter (1…65535).
Value
Defines where the contents (reading) of the channel comes from:
•Input: Measurement result from the wireless transmitter.
•TcB, TcC, TcD, TcE, TcG, TcJ, TcK, TcL, TcN, TcR, TcS or, TcT: Used thermocouple linearization if
transmitter in question can measure temperature with thermocouples but cannot perform the
necessary thermocouple linearization by itself.
•Batt: Battery level* of the transmitter.
•CJ: Cold junction temperature of the transmitter.
•RSL: Received signal level.
•Interval: Tells how many seconds between successive receptions from the transmitter.
•Age: Tells how many seconds have passed since last reception from the transmitter.
•Jumps: The number of repeaters the data from the transmitter has passed through.
Reading
Channel reading.
Info
Shows information on the corresponding transmitter. Signal level, battery level*, seconds elapsed from the
last reception, transmitter type and number of repetitions.
* “Batt”reading is relative value where reading 2.5 corresponds to empty battery and reading 3.0
corresponds to full battery.
Repeater
If “ID filter” is checked in Repeater submenu, only those IDs will be repeated that have this setting on.
Ch1
ID
Value
Reading
Info
Repeater
Channels
Timeout[min]
Count
Ch1
...
Ch100

12

13
Repeater
Repeater
ID filter
Extra bytes
Max jumps
Replace with RSL
Advanced Options
Weak repeater filter
Compatibility mode
Repeater submenu
Repeater
•Off: Repeater function is off.
•On: Repeater function is on.
•Jumper: Jumper controls the repeater function. Default setting.
ID filter
If checked, only those IDs that are checked in Channels/ChX/Repeater
submenu will be repeated. Default unchecked.
Extra bytes
If checked, the device adds additional information to the repeated data packets: Number of hops and the
received signal strength. Group of repeaters can deliver received signal level of the weakest link. Default
unchecked.
Max jumps
If the “Extra bytes” setting is checked in all repeaters in the system, this setting can limit the number of
repeats (jumps) and thus prevent an endless repeating cycle of data packets. Default value 15.
Replace with RSL
This setting is reserved for testing purposes only. When checked, the original measurement value of the
repeated data is replaced with the received signal level. Default unchecked.
Advanced Options submenu
Weak repeater filter
When checked, the repeater function will not repeat already repeated data
packets that have a received signal level weaker than already received. Default
checked.
Compatibility mode
When checked, the receiver uses an alternate signal processing algorithm. Try different setting if you have
problems with reception in low signal level conditions. Default checked.
Monitor menu
Monitor menu contains some information that can be useful during installation and which may facilitate
monitoring the system's operating condition.
Mon
Uptime[h]
LastID
LastType
Last RSL[dBm]
RSL[dBm]
Switches

14
Operation
FT20 has one diagnostic LED that shines through the case of the device. This LED blinks slowly when the
unit is operational but not receiving any radio data packets at the moment, and blinks rapidly when radio
data packets are being received.
Receiver operation
Promolog data acquisition software
PromoLog is a modular data acquisition software allowing you to design customized data collection and
monitoring applications matching your needs.
Applications are created by dragging suitable modules from library onto the screen. Both wireless and
wired transmitters are supported practically without channel limits. You can also place photos or drawings
on the background.
Serial commands
In case PromoLog data acquisition software is not used for reading data from the device, then following
protocols can be used to read data from the device:
•Nokeval SCL protocol (page 15).
oReading with SCL commands.
oReading with Nopsa commands over SCL protocol (page 19).
•Modbus RTU protocol (page 16).
oReading Modbus registers.
oReading with Nopsa commands over Modbus protocol (page 19).

15
SCL protocol
A full specification of the Nokeval SCL protocol can be downloaded from Nokeval WWW site. In short, the
command frame consists of an address byte (bus address+128), a human-readable command, an ETX
character (ASCII 3) and an XOR checksum of all bytes excluding the address byte. A normal response
consists of an ACK (ASCII 6), a human-readable response, an ETX and an XOR checksum of all the bytes
including the ACK. An error response is similar, but the ACK is replaced by a NAK (ASCII 21).
Nokeval SCL always uses 8N1 parity.
SCL Commands
This device supports the following SCL commands:
TYPE ?
Returns the model name and software version of the device.
SN ?
Returns the device's serial number, for example ”A123456”.
MEA CH <ch> ?
Returns the last received value from the channel <ch>. The response may contain digits 0-9, minus sign, and
a decimal point. The scientific representation 1.00E-3 is not used. If the channels result is NaN (Not A
Number), device returns ------.
MEA SCAN <first> <last>
Returns the last received values of channels <first> to <last> separated with a space. E.g. MEA SCAN 1 3 will
return the values of channels 1, 2, and 3. An example response: 25.6 29.1 0. If the channels result is NaN
(Not A Number), device returns ------
DBG 1 ?
Returns the oldest unread data packet from the ring buffer.
DBR 1 <xx> ?
Returns a data packet from the ring buffer at location <xx>.
DBX
Clears the ring buffer (marks all data packets as read).
DBS 1 ?
Returns the size of the ring buffer.
N <hexadecimal data>
Encapsulating a Nopsa command in SCL. The Nopsa command is converted to hexadecimal characters
without spaces. E.g. querying the serial number: N 0102. The device responds with hexadecimal characters
carrying a Nopsa response. See section “Nopsa commands”.
MN <hexadecimal data>
A legacy command for encapsulating Meku configuration commands in SCL protocol. Using Nopsa is
recommended.

16
Modbus protocol
Supported Modbus RTU commands:
• 3 Read Holding Registers: Read settings.
• 4 Read Input Registers: Read result values.
• 6 Write Single Register: Change settings.
• 16 Write Multiple registers: Change multiple settings at once.
• 17 Report Slave ID: Device type information.
• 109 Meku: This is used by Mekuwin configuration software.
• 110 Nopsa: This is used to transport Nopsa protocol on Modbus.
Command 17 returns 0x11 <byte count> 0x00 0xFF, followed by for example “FT20 V1.0 A123456”
Maximum Modbus packet length is 240 bytes. This affects the maximum possible register count that can be
accessed simultaneously with commands 3, 4 and 16.
When settings are changed, the device will save the settings instantly into the configuration EEPROM
memory. If serial settings are changed, new settings will take effect only after cycling the device power, it
works this way so that all serial settings can be done at once without breaking the serial connection.
Data types:
• BOOL: On/off value. 0=off, 1=on, in lower (right hand side) byte.
• BYTE: 8-bit value. Only lower (right hand side) byte used.
• WORD: 16-bit value.
• ENUM: List of alternatives.
• FLOAT: 32-bit float IEEE 754. Least significant word first, inside word most significant byte first.
• STRINGZ: Zero terminated string. In one Modbus register data is presented as most significant byte first.

17
Input registers
0..1
Ch1\Reading
FLOAT (LSW, MSB)
Signed
2..3
Ch2\Reading
FLOAT (LSW, MSB)
Signed
…
…
198..199
Ch100\Reading
FLOAT (LSW, MSB)
Signed
200..201
Ch1\Reading
FLOAT (MSW, MSB)
Signed
202..203
Ch2\Reading
FLOAT (MSW, MSB)
Signed
…
…
398..399
Ch100\Reading
FLOAT (MSW, MSB)
Signed
400..401
Ch1\Reading
FLOAT (LSW, LSB)
Signed
402..403
Ch2\Reading
FLOAT (LSW, LSB)
Signed
…
…
598..599
Ch100\Reading
FLOAT (LSW, LSB)
Signed
600..601
Ch1\Reading
FLOAT (MSW, LSB)
Signed
602..603
Ch2\Reading
FLOAT (MSW, LSB)
Signed
…
…
798..799
Ch100\Reading
FLOAT (MSW, LSB)
Signed
1000
Ch1\Reading
WORD
Signed
1001
Ch2\Reading
WORD
Signed
…
…
1099
Ch100\Reading
WORD
Signed
2000
Ch1\ID
WORD
Unsigned
2001
Ch1\Type
ENUM
See Table E1
2002
Ch1\Battery
WORD
Unsigned *
2003
Ch1\Signal
WORD
Unsigned
2004
Ch1\Flags
WORD
See Table E2
…
Table E1
Value
Type
0
MTR260
1
MTR262
2
MTR264
3
MTR265
4
MTR165
5
FTR860
6
CSR260
7
Unknown
Table E2
Bits
Bits
0..6
Age counter [min]
7
Data changed
* Battery register value is relative value where reading 25 corresponds to empty battery and reading 30
corresponds to full battery.
Measured values are available in 4 different word/byte order formats in registers below 1000.
All floats are 32-bit floating point numbers according to IEEE 754.
•In registers 0...63: Least significant word first, inside word most significant byte first.
•In registers 200…263: Most significant word first, inside word most significant byte first.
•In registers 400...463: Least significant word first, inside word least significant byte first.
•In registers 600...663: Most significant word first, inside word least significant byte first.
•In registers 1000...1031 results of channels are presented using fixed point notation with 1 decimal.
In example integer 150 means 15.0.
Note! In case the reading is too old (older than the timeout parameter configured in the menu specifies) or
there is no reading for a channel then float value is Quiet NaN ( 0x7FC00000 ) and word value is 0x7FFF.

18
Holding registers
Address
Name
Type
Values
2000
Conf\Serial\Protocol
ENUM
See table E3
2001
Conf\Serial\Baud rate
ENUM
See table E4
2002
Conf\Serial\Bits
ENUM
See table E5
2003
Conf\Serial\Address
BYTE
Unsigned 0...247
2004
Conf\Channels\Timeout[min]
BYTE
Unsigned 1...255
2005
Conf\Channels\Count
BYTE
Unsigned 0...100
2006
Conf\Channels\Ch1\ID
WORD
Unsigned
2007
Conf\Channels\Ch1\Value
ENUM
See table E6
2008...2009
Conf\Channels\Ch1\Reading
FLOAT
Signed
2010...2025
Conf\Channels\Ch1\Info
STRINGZ
Len=32
2026
Conf\Channels\Ch1\Repeater
BOOL
2027
Conf\Channels\Ch2\ID
WORD
Unsigned
2028
Conf\Channels\Ch2\Value
ENUM
See table E6
2029...2030
Conf\Channels\Ch2\Reading
FLOAT
Signed
2031...2046
Conf\Channels\Ch2\Info
STRINGZ
Len=32
2047
Conf\Channels\Ch2\Repeater
BOOL
…
4106
Conf\Repeater\Repeater
ENUM
See table E7
4107
Conf\Repeater\ID filter
BOOL
4108
Conf\Repeater\Extra bytes
BOOL
4109
Conf\Repeater\Max jumps
BYTE
Unsigned 1...15
4110
Conf\Repeater\Replace with RSL
BOOL
4111
Conf\Advanced Options\Weak repeater filter
BOOL
4112
Conf\Advanced Options\Compatibility mode
BOOL
Enum values
Table E3
Value
Protocol
0
SCL
1
ModbusRTU
Table E5
Value
Bits
0
8N1
1
8N2
2
8E1
3
8O1
Table E6
Value
Value
0
Input
1
TcB
2
TcC
3
TcD
4
TcE
5
TcG
6
TcJ
7
TcK
8
TcL
9
TcN
10
TcR
11
TcS
12
TcT
13
Batt
14
CJ
15
RSL
16
Interval
17
Age
18
Jumps
Table E4
Value
Baud rate
0
300
1
600
2
1200
3
2400
4
4800
5
9600
6
19200
7
38400
8
57600
9
115200
10
230400
Table E7
Value
Repeater
0
Off
1
On
2
Jumper

19
Nopsa commands
Nopsa is a command language which enables measurement data and configuration data transfer. Nopsa
can be used to transfer data between devices or from host to device. Nopsa needs some transfer layer
protocol, which takes care of addresses, transfer error management and packet length. This device
supports Nopsa commands over either Nokeval SCL or Modbus RTU protocols.
Supported Nopsa commands
•1/0 (Type) Read device type
•1/1 (Version) Read device version
•1/2 (Serial number) Read serial number of the device
•1/3 (Description) Read short description of the device
•1/4 (Command set) Read command set number for the device
•1/5 (Serial buffer size) Read serial buffer size
•1/7 (Radio ID) Read radio ID
•1/16 (Reset) Reset device
•1/32 (Meku) Pass Meku configuration commands to device
•2/0 (Out value request) Read channel reading
•2/1 (Out resource request) Read channel metadata (name, data type)
•4/0 (Buffer info) Read buffer size and current write position
•4/1 (Find oldest from buffer) Move read position to oldest entry in buffer
•4/2 (Find newest from buffer) Move read position to newest entry in buffer
•4/3 (Read buffer with index) Read specific data entry from buffer
•4/4 (Read next from buffer) Read data entry from buffer and move read position to next
•4/5 (Reread last) Returns last read operation contents
•7/10 (Carrier) Turn carrier on or off.
•7/11 (Test packet) Send RF test packet

20
Transport protocol SCL
When Nopsa packets are transported on SCL data is converted to hexadecimal notation (0-9 and A-F). One
Nopsa byte will become 2 bytes. No spaces between characters. Packet starts with SCL command N and a
space.
ID ’N’ ’ ’ Nopsa-packet in hexadecimal ETX BCC
Response is transferred also same way in hexadecimal, but N command is not appended.
ACK Nopsa-response in hexadecimal ETX BCC
Transport protocol Modbus RTU
Command function 110 (0x6E) is reserved for Nopsa commands in Modbus free command area. After
function code there is one byte which informs Nopsa packet length.
ID 0x6E Length Nopsa-packet CRC
Response is in same format.
0x6E Length Nopsa-packet CRC
Nopsa response
Each response contains first status byte.
Bit
Description
.7
Internal error. Device has detected some internal malfunction. In example flash memory don’t
respond. More detailed error information need to be request by Meku Diag.
.6
External error. Device has detected some external error. More detailed error information need to
be requested by Meku Diag.
.2-.0
Command progress:
* 0 = OK
* 1 = Command is not supported
* 2 = Parameter error
* 3 = Device is unable to process the command at the moment (busy)
* 4 = Command is legal, but some error caused it to fail
If response is not OK, then the response data is not response for the command. Command specific data
begins immediately after status byte.