Contemporary Control Systems MR-AI8 User Manual

Analog Input Module
MR-AI8

11083213

1. Description

The Modbus module with 8 individually configurable
resistance or voltage inputs is designed for local switching
operations. It is suitable to record resistance or voltage values of
for example passive and active temperature sensors electrical
ventilation or mixing valves, valve positions etc. The inputs are
universally configurable and can be scanned via a Modbus-Master.
Setting of the slave address, bit rate and parity is done with the
two address switches (x1 / x10) on the front. Possible settings
are addresses 00 to 99 and baud rates 1200, 2400, 4800, 9600,
19200, 38400, 57600 und 115200 Bd.

The device does not participate in bus communication if the
address is 00 (reserved for broadcast commands).

2. Declaration of Conformity

The device was tested according to the applicable standards.
Conformity was proofed. The declaration of conformity is
available at the manufacturer BTR NETCOM GmbH.

Notes Regarding Device Description

These instructions include indications for use and mounting of
the device. In case of questions that cannot be answered with
these instructions please consult supplier or manufacturer.

The indicated installation directions or rules are applicable to
the Federal Republic of Germany. If the device is used in other
countries it applies to the equipment installer or the user to
meet the national directions.

Safety Instructions

Keep the applicable directions for industrial safety and preventi­on of accidents as well as the VDE rules.

Technicians and/or installers are informed that they have to
electrically discharge themselves as prescribed before installati­on or maintenance of the devices.

Only qualified personnel shall do mounting and installation
work with the devices, se e section “qualified personnel”.

The information of these instruc tions have to be read and un­derstood by every person using this device.

7170/899289

Symbols

Warning of dangerous electrical voltage

Dange r

means that non- obser vance may cause risk of life,
grievous bodily harm or he avy material damage.

Qualified Personnel

Qualified personnel in the sense of these instructions are
persons who are well versed in the use and installation of such
devices and whose professional qualification meets the require­ments of their work.

This includes for example:

• Qualification to conne ct the device according to the VDE
specifications and the local regulations and a qualific ation to
put this device into operation, to power it down or to activate
it by respecting the internal directions.

• Knowledge of safety rules.

• Knowledge about application and use of the device within the
equipment system etc.

Modbus Interface

Protocoll Modbus RTU
Transmission rate 1200 ... 115200 Bd
(factory set ting 19200 Bd Even)
Cabling RS485 two wire bus with voltage
equalizing cable in bus / line
topology

Supply

Operating volt age range 20 ... 28 V AC/DC (SELV)
Current consumption 65 mA (AC) / 25 mA (DC)
Relative duty cycle 100 %

Input

Resistance range 40 W to 4 MW
Voltage input 0 ... 10 V DC
Resolution 1 mV
Error
Voltage input about ±10 mV
Resistance input < 12 kW = 0,1 % / > 12 kW = 1 %

Housing

Dimensions Wx HxD 2.0 x 2.8 x 2.6 in. (50 x 70 x 65 mm)
Weight 104 g
Mounting position any
Mounting standard rail TH35 per IEC 60715
Mounting in series the maximum quantit y of modules
without space connected in line is limited to 15 or to
a maximum power consumption of
2 Amps (AC or DC) per conne ction to
the power supply.
For any similar block of additional
modules a separate connection to the
power supply is mandatory.
Material
Housing Polyamide 6.6 V0
Terminal blocks Polyamide 6.6 V0
Cover plate Polycarbonate
Type of protection
(IEC 60529)
Housing IP40
Terminal blocks IP20

Terminal blocks

Supply and bus
4 pole ter minal block max. AWG 16 (1,5 mm²) solid wire
max. AWG 18 (1,0 mm²) stranded wire
Wire diameter min. 0.3 mm up to max. 1.4 mm
(terminal block and jumper plug are
included to each packing unit)
Module connection
Input/Output max. AWG 12 (4.0 mm²) solid wire
max. AWG 14 (2.5 mm²) stranded wire
Wire diameter min. 0.3 mm up to max 2.7 mm

Temperature range

Operation -5 °C ... +55 °C
Storage -20 °C ... +70 °C
Protective circuitr y polarity reversal protection of
operating voltage
polarity reversal protection of supply
and bus

Display

Operating and bus activity green LED
Error indication red LED

4. Wiring Diagram3. Technical Data

5. Connection Diagram

METZ CONNECT | Im Tal 2 | 78176 Blumberg | Germany | Phone [phone] | Fax [phone]
Distributed by RIA CONNECT GmbH and BTR NETCOM GmbH
Mounting instruction see www.metz-connect.com

6. Mounting

Power down the equipment

Mount the module on standard rail (TH35 per IEC 60715 in
junction boxes and/or on distribution panels).

Installation
Electric ins tallat ion and device te rminat ion shal l be done by

qualified persons only, by respecting all applicable
specifications and regulations.

Plug in th e terminal bloc k for bus co nnection

21

Conne ct the ca ble for bus supply

5 mm

43

Mounting in series

65

The module can be aligned w ithout interspace. Use the jumper
plug to connect bus and supply voltage when the modules are
mounted in series.

The max imum quantity o f modules conne cted in l ine is lim i­ted to 15 or to a ma ximum power consumption of 2 Amps
(AC or DC ) per connecti on to the power supply. For any
simila r block of additi onal mod ules a se parate co nnection
to the power suppl y is manda tory.

7. Bit rate and Parity setting

The bit rate and parity can be set in the programming mode
when ajumper is plugged behind the front cover of the module.
This jumper is removed in normal mode. A connection to the
bus is not require d during bit rate setting.

The bit rate of the modules can be set in the following way:

1. remove the front cover of the module;

2. plug a jumper to the two middle pins of the 4 pole header
between the red and green LED ( Á);

3. set the desired parity and bit rate with the address s witches
(Â) in accordance to the chart below.

7

C2C2C2

24V 24V

+24V

GND

B+

A -

ERROR



MODBus RTU

MR-AI8

182

C2

4. switch on the supply voltage of the module; it is now per­manently saving the bit rate in an EEPROM;

5. switch off the supply voltage of the module;

6. remove the jumper from the header and place the front
cover.

Switch

1 2 3

x10

C26

x10



x1

Jumper below
the faceplate

3C2

BUSY

5

S

+24V

GND

B+

A -

1

2

24V

J

3

15V

4

4

C2C2S

Parity even odd none

Switch

1 2 3 4 5 6 7 8

x1

Bitrate

1200 2400 4800 9600 19200 38400 57600 115200

(Bit/s)

If the settings differ from the settings specified in the chart the
factory setting applies.

Factor y setting: 19200 Bd Even

8. Jumper Positions for Voltage feeding of Ac­tive Sensors

7

C2C2C2

24V 24V

+24V

GND

B+

A -

ERROR

MODBus RTU

MR-AI8

182

C2

7

C2C2C2

24V 24V

+24V

GND

B+

A -

ERROR

MODBus RTU

MR-AI8

182

C2

5

S

C26

+24V

GND

x10

B+

x1

BUSY

4

3C2

5

C26

x10

x1

BUSY

4

3C2

1

2

3

4

C2C2S

1

2

3

4

C2C2S

+24V

GND

A -

S

B+

A -

Jumper below
the faceplate

Jumper in
bottom position
contacts S
=15VDC
(factory setting)

Jumper below
the faceplate

Jumper in
top position
contacts S
=24VAC/DC

9. Connection examples

active

passive
sensor

7

C2C2C2

24V 24V

+24V

GND

B+

A -

ERROR

Pullup
resistance

MODBus RTU

MR-AI8

182

C2

Semiconductor

sensor

D

sensor

Ub

0..10V

GN

5

S

C26

+24V

GND

x10

B+

x1

A -

1

BUSY

2

24V

J

3

15V

4

4

C2C2S

3C2

10. Software Description

10.1 I/O Commands

„04 (0x04) Read Input Registers“

Request:

Valid Starting Address 0 .. 15
Valid Quantity of Registers 1 .. 16 (1 to 8 inputs)

Response:

Byte Count 2 x Quantity o. R.
Registers Values Quantity o. R x 2 Bytes

Input

Register

Information

1 0-1

2 2-3

3 4-5

4 6-7

5 8-9

6 10-11

7 12-13

8 14-15

Figure 1

Sign

Byte 1 Bit 7 Byte 1 Bit 6..0 Byte 2 Bit 7 Byte 2 Bit 6..0 Byte 3 Byte 4

Configuration Registers
Input circuit and measuring range, data type and value unit and

the sensor characteristic for usual temperature sensors are set for
the 8 inputs with the 8 configuration registers.

Register contents is stored in an EEPROM.
Modbus functions:

“03 (0x03) Read Holding Registers” (max. 20 at once)
“06 (0x06) Write Single Register”
“16 (0x10) Write Multiple Registers” (max. 20 at once)

Holding Register 0-15 Offset Register is added to the measured
value in 2 succeeding registers,
(Input 1 = Register 0 - 1)
Float in both or Signed Integer 16 in the
first one, same as for measured value

Holding Register 16-23 Configuration register (EEPROM)
used to set measuring range,
data type of the measure d value
(Float / Integer 16),

unit of the measured value and the
sensor characteristic

(Input 1 = Register 16)
Holding Register 24-63 Register for interpolation charts

(EEPROM),
alternately temperature and resistance,

Float in two succeeding registers

Configuration Register for voltage or resistance measurement:

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Values are supplied in 2 registers (4 Bytes).

Data type in registers can be configured
(see Registers 16 to 23):

Float value needs 2 registers (fig. 1)

signed int value is in 1st register

signed int 0 fills 2nd register

Value remains 0 until a measurement takes place

Data types composed from 2 registers start at an even
address

Exponent Exponent Mantisse Mantisse Mantisse

0 0 range number

METZ CONNECT | Im Tal 2 | 78176 Blumberg | Germany | Phone [phone] | Fax [phone]

Distributed by RIA CONNECT GmbH and BTR NETCOM GmbH
Mounting instruction see www.metz-connect.com