CIRCUIT DESIGN MU-4 RS232C User manual

OG_MU2-RIK_v10e Circuit Design, Inc.
OPERATION GUIDE
Embedded low power radio modem MU-4
MU-4 RS232C Interface Board
MU4-RS2IF
Operation Guide
Version 1.0 (Sep. 2020)
CIRCUIT DESIGN, INC.,
7557-1 Hotaka, Azumino-city
Nagano 399-8303 JAPAN
Tel: +81+(0263)-82-1024
Fax: +81+(0263)-82-1016
E-mail: [email protected]
Web site: https://www.cdt21.com/

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OPERATION GUIDE
Chapter 1 The MU4-RS2IF 2
1.1 Outline 2
1.2 System Requirements 3
1.3 Product Name and Part Number 4
1.4 Board and contents 4
Chapter 2 The MU4-RS2 (MU-4 + MU4-RS2IF) 5
2.1 Part Names and Functions 5
2.2 Block Diagram 6
2.3 Main Specifications 7
2.4 Channel Table 7
2.5 External dimensions 8
2.6 Circuit Diagram 9
Chapter 3 How to Use the MU4-RS2 10
3.1 System Configuration Example 10
3.2 Resetting 11
3.3 Initializing 11
3.4 Connection example 11
Chapter 4 How to Design a User System 12
4.1 Embedding the Product 12
4.2 The antenna 13
4.3 Regulatory Compliance 13
4.4 Cautions 13
Chapter 5 How to Develop a Program 14
Contents

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OPERATION GUIDE
The MU-4 RS232C interface board, MU4-RS2IF is a development board for planning radio system with an RS232C
interface connection function that uses the embedded low power radio modem MU-4. Purchasing the board enables
you to begin evaluating communication with the MU-4 immediately.
The board with MU-4 can be controlled using simple dedicated commands, so that the developer can concentrate
on designing the protocols for transmitting and receiving data, without needing to be aware of control of the radio
component. Since the control program created by the user accesses the host COM port, users can apply their fund
of knowledge of RS232C technology.
◼1.1.1 The MU4-RS2
In this operation guide, for the sake of convenience, the MU-4 RS232C interface board, MU4-RS2IF with the
embedded low power radio modem MU-4 mounted on it is referred to as the MU4-RS2. Before using the board,
mount the MU-4 on the MU4-RS2IF. When mounting the MU-4, observe the following cautions, and carry out the
soldering carefully.
Cautions for soldering
•To prevent damage to the connectors, solder the joints quickly.
•Avoid connection defects.
•In order to prevent damage to the MU-4 and the MU4-RS2IF from static electricity, earth yourself
before starting work.
•Do not cause short circuits by dripping solder on the board.
Important
The development board does not include module MU-4. Please make sure to order it if needed.
It is not possible simply to replace communication using existing RS232C system equipment connected
with a cable, with MU4-RS2 wireless communication. The hardware and software must be designed
specifically for the MU-4.
MU4-RS2
-
MU4-RS2IF
-
MU-4-434
-
+
=
Chapter 1 The MU4-RS2IF
1.1 Outline
Caution

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OPERATION GUIDE
◼1.1.2 Explanation of terminology
The meaning of the terminology used in this Operation Guide is as follows.
1. The “Evaluation program and driver” is the zip file that is available from the Circuit Design website, that
contains the setup program, Operation Guide and so on.
The program is located on MU-4 documents page.
2. The “Evaluation Program” is a program for evaluation of the MU-2-R and series of products, called the
MU-2-R Evaluation Software Program MU2-ESP. After installation it is found inside the “Circuit Design” folder
that appears on the desktop of your PC. MU-4 that is compatible with commands and interface, can also use
this program.
◼1.1.3 Features
◆Circuit diagrams for making user systems are publicly available.
◆Compact size (47 × 71 × 18 mm) fits in a small housing.
◆Features of the MU2-ESP evaluation program;
1. You can issue all commands for controlling the interface board with module.
2. There is a test program for checking the communication performance of the interface board with module.
3. There is an air monitor function for checking the status of radio waves in the field.
◼1.1.4 Applications
◆Serial data transmission
Energy monitoring, data monitoring devices, handy terminals, barcode readers
◆Telecontrol
Remote control for construction machinery, display devices, motor control, lifters
Remote control of FA equipment
◆Telemetry
Water level monitors for rivers and dams, temperature and humidity gauges, rain gauges, pressure gauges,
voltmeters, ammeters
Systems used with MU4-RS2IF must meet the following conditions.
1. OS: Windows 8 and 10
2. Hard disk capacity: 30 MB or more
3. Memory: 64 MB or more
1.2 System Requirements

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OPERATION GUIDE
Product name: MU-4 RS232C interface board Part number: MU4-RS2IF
The board and contents are as follows. First, please check that you have all the items.
◼1.4.1 Accessories
1. MU-4 RS232C interface board MU4-RS2IF 1
2. Battery holder 1
3. Spacers (used as legs) 10 mm 4
4. Screws for spacers M 2.6 × 6 mm 4
MU4-RS2IF x 1
Screw(M2.6 x 6mm) x 4
Spacer(10mm) x 4
Battery holder x 1
1.3 Product Name and Part Number
1.4 Board and contents

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OPERATION GUIDE
[04]λ/4 lead antenna
[05]4-mounting holes
[06]Initialize button
[07]Power LED
[08]Power switch
[09]Power terminal
[10]RS232 connector(D-Sub 9-pin)
[01]RX-LED
[02]TX-LED
[03]MU-4
RF
GND
VCC
RXD
CTS
INI
RXM
DO
RXL
TXD
RTS
MOD
RST
DI
TXL
MU-4-434
[01] RX-LED: On when data is received.
[02] TX-LED: On when data is transmitted.
[03] MU-4: A low power serial data transmission modem.
[04] λ/4 Lead antenna: A λ/4 long lead antenna (ANT-LEA-01, ANT-RIG-01-R).
[05] Mounting holes: 3Φholes for mounting
[06] Initialize button: Resets the MU-4 mounted on the MU4-RS2IF to the factory default settings. Follow the
procedure below.
1. Turn on the power while pressing the initialize button.
2. Turn off the power and on once again after a while (approx. 5 seconds).
[07] Power LED: The LED comes on when the power switch is turned on.
[08] Power switch: A power switch. Check that the power terminal is connected before turing it on.
[09] Power terminal: The connector for the power supply. Connect a 9 V battery with the battery snap provided.
* If you connect to a power supply other than a 9 V dry battery, ensure that it is DC +3.2 V to DC +12 V. Be sure to
connect the power supply with the correct polarity. Add a noise filter to the power line.
[10] RS232C connector (D-Sub 9-pin socket): A D-Sub 9-pin socket for RS232C. Connect the RS232C straight
cable provided. You can also supply power from the RS232C connector pin No.1. In this case, take the voltage drop
(approx. 0.6 V) due to the diodes into consideration. For details, refer to the circuit diagram.
2.1 Part Names and Functions
Chapter 2 The MU4-RS2 (MU-4 + MU4-RS2IF)

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OPERATION GUIDE
RS232C
level conversion
2
1
VCC
GND
MU-4
λ/4
Lead antenna
Regulator
+3v
2
4
5
6
7
1
8
9
12 11
10
13
14 INI
RXD TXD
RTSCTS
MOD
RSTRXM
RF
GND
VCC
DI
DO
RXL
CN1
+
-
DC +3.2v～+12v
LED1
LED3
LED2
Power terminal
SW1
Power switch
1
RXD 2
TXD 3
DTR 4
GND 5
DSR 6
RTS 7
CTS 8
9
CN2
D-Sub 9pin
male
SW2
VCC
External
power LED terminal
External
Rx LED terminal
External
Tx LED terminal
3
TXL
2.2 Block Diagram

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OPERATION GUIDE
◼2.3.1 General specifications
◼2.3.2 RS232C interface specifications
Communication method
Serial communication (RS232C format)
Synchronization
Asynchronous
Data speed
1,200 / 2,400 / 4,800 / 9,600 / 19,200 / 38,400 / 57,600 bps
Flow control
RTS/CTS hardware flow control
Other parameters
Data length 8 bits, no parity, 1 or 2 stop bits
RS232C output level
+/-5 V (power 3.2 V)
Connector
D-Sub 9-pin male
Refer to the operation guide of the MU-4 mounted on the MU4-RS2IF for the channel table. The frequency band is
shown on the label of the MU-4.
Parameter
Specification
Unit
Remark
Supply voltage
DC +3.2 to +12 V
V
Consumption current
Transmitting: 48 / Receiving: 28
mA
Operating temperature
-20 to +65
ºC
The operation range varies with the
temperature conditions.
LED indicator
Tx, Rx, Power
Power connector
Terminal block (2 pin)
Switch
Power, initialize
External dimensions
47 × 71 × 18 (W × D × H)
mm
Including the connector.
Not including the antenna.
Unit weight
24
g
2.4 Channel Table
2.3 Main Specifications

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OPERATION GUIDE
MU4-RS2 = MU-4 + MU4-RS2IF
2.5 External Dimensions
30.8
25
7.9
14.2
6.65
17.4
47
40
64 57
51
1.6
7.1
λ /4 lead antenna
180
4- φ 3
RF
GND
VCC
RX D CTS
INI
RXM
DO
RXL
TXD
RTS
MOD
RST
DI
TXL
MU-4-434

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OPERATION GUIDE
2.6 Circuit Diagram
MU-4

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OPERATION GUIDE
Group1(1:N system)
Same area
UI=0055
GI=02
EI=01
UI=0055
GI=02
EI=02
UI=0055
GI=02
EI=03
UI=0055
GI=02
EI=04
MU2-RS2
MU4-RS2
Group2(1:N system)
Group3(1:N system)
Note : UI=User ID GI=Group ID EI=Equipment ID DI=Destination ID
Since it is treated in the same way as the MU-4, refer to “Chapter 4 How to Use the MU-4” in the MU-4 operation
guide.
Chapter 3 How to Use the MU4-RS2
3.1 System Configuration Example

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OPERATION GUIDE
Using the reset command @SR, the MU4-RS2 can be reset to the status when the power was turned on.
The parameters set in the EEPROM remain unchanged.
Reset the unit to the factory default settings if communication with the MU-4 mounted on the MU4-RS2 is not
possible or if you are uncertain of the internal settings.
How to initialize the MU-4
Turn on the power while pressing the initialize button. Then turn the power off and on once again to reset the unit to
the default settings. For details of the default status, refer to the default values for each command in the MU-4
Operation guide.
The MU-4 can also be initialized using the initialize command @IZ.
Status after initializing
The values of the main parameters after initializing are as follows.
1. Link related parameters
User ID: UI = 0000, Group ID: GI = 00, Equipment ID: EI = 01, Destination ID: DI = 01, Channel = 0 channel
2. UART related parameters
Baud rate = 19,200 bps, parity = none, stop bit = 1
3. Parameters related to internal operation
Mode = command
The diagram below is an example of how to connect the MU4-RS2 and the single-chip CPU. Insert an RS232C
transceiver in the CPU signal line.
Since the MU4-RS2 DTR line is connected to the MU-4 MODE terminal, be sure to control the level in accordance
with the MU-4 mode being used.
2
1
VCC
GND
MU-4
λ/4
Lead antenna
Regulator
+3v
2
3
4
5
6
7
1
8
10
11
12
9
13
14
INI
RXD
TXD
RTS
CTS
MODE
RESET
DI
RF
GND
VCC
AF-MON
DO
TX-LED
RX-LED
+
-
LED1
LED2
LED3
CN1
Power terminal
DC +3.2v～+12v
SW1
Power switch
1
RXD 2
TXD 3
DTR 4
GND 5
DSR 6
RTS 7
CTS 8
9
CN2
D-Sub 9pin
male
SW2
initialize
1
2 RXD
3 TXD
4 DTR
5 GND
6 DSR
7 RTS
8 CTS
9
RS232C
level conversion
RS232C
level conversion
CPU
RXD
TXD
RTS
CTS
Output Port
(Mode control)
Straight cable
User system
MU4-RS2(RS232C interface board + MU-4)
3.3 Initializing
3.2 Resetting
3.4 Connection example

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OPERATION GUIDE
The MU4-RS2 is not optimized from the point of view of physical functionality for embedding in final products. When
designing systems that use the RS232C interface, we recommend that you refer to the circuit diagram of the
MU4-RS2 given in this operation guide, and implement the interface part in your user system.
When using the MU4-RS2 without further modification, ground the unit from the MU-4 leg nearest the antenna (the
leg on the soldered side) to the case. Moreover, determine the position and number of grounds through testing.
If you house the product in a case, determine the position of the ground and antenna through a variety of tests.
External LED terminals have been newly added to this product. In addition, if you attach LEDs to the case, connect
them with inch-pitch through holes with reference to the diagram below.
MU-4
RS232C cable
User PC
Antenna *2
1
2
3
4
5
6
Power LED
Tx LED
Rx LED
GND
+3v
+3v
*1
100pF
100pF
MU4-RS2
100pF
*1: Solder the terminal lug etc. and connect it to the user case
ground. Determine the connection point with various tests.
*2: If the antenna is bent to fit inside, the communication
range falls and communication errors become frequent. Do
Not put the antenna inside a metal case.
*3: Terminal pitches are all in inch sizes.
D-Sub
For external
Powe LED *3
For external
Tx LED *3
For external
Rx LED *3
2
4
1
3
56
Connecting external LEDs
.・To prevent noise, attach a ceramic
capacitor of about 100 pF to the LED.
・Terminals 1, 3, and 5 there are 1kΩ
resistors in the MU4-RS2.
Chapter 4 How to Design a User System
4.1 Embedding the Product

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OPERATION GUIDE
In systems where a non-directional antenna is required, it is important that the antennas of the transmitting station
and target stations stand vertically in order to exploit communication performance to the maximum. If the planes of
polarisation of the radio waves do not match, receive sensitivity may drop significantly.
Note that if, for reasons peculiar to the equipment, the antenna must be inside the case, communication
performance will be very significantly degraded when handled in the following ways, since these methods
contravene antenna theory. It is the responsibility of the user to test performance thoroughly when designing
equipment.
1. Putting the antenna inside a metal case
2. Wrapping the antenna around the circuit board
3. Locating the antenna beside the ground pattern of the circuit board
4. Fitting the antenna inside by bending it
5. Cutting the antenna to make it shorter
The antenna provided with the MU-4 is a 1/4λ whip antenna. Whip antennas are antennas that substitute the ground
as one end of a dipole antenna. For this reason the ground has a very important meaning. Although the main unit of
the MU-4 has the function of a ground, in order to exploit its performance fully, connect it to the largest possible
ground pattern when mounting the MU-4 on your circuit board.
In addition, in the case of two way communication between fixed stations, inclining the whip antenna of the MU-4
forwards may increase its communication range. Carry out tests in the specific environment of use.
The MU4-RS2 is a product that uses an RS232C interface to interface with external equipment. If the MU4-RS2 is
used embedded in a final product, the regulatory compliance assessment in accordance with the RE Directive
depends on the final product. Regulatory compliance assessment should be carried out on the responsibility of the
manufacturer of the final product.
For details of the CE mark, refer to the MU-4 Operation Guide.
Point:
The MU-4 radio modem has passed the regulatory compliance assessment in accordance with RE Directive a
stand-alone product, and has received the CE mark.
1. Devise ways of isolating the unit as far as possible from noise from other embedded equipment and from other
sources of noise.
2. Arrange the system equipment so that it will not be covered by the operator’s hand or the like.
3. The MU-4 does not have a waterproof structure. If the antenna is located outside the main unit, use a structure
that prevents water droplets from entering the case.
4.2 The Antenna
4.3 Regulatory Compliance
4.4 Cautions

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OPERATION GUIDE
The program that controls the MU4-RS2 (MU-4 + MU4-RS2IF) is a program that accesses the COM port.
The method of developing a program is basically the same as for the MU-4, except for accessing a virtual COM port.
Refer to “Chapter 6 How to Develop a Program” in the MU-4 Operation Guide.
Chapter 5 How to Develop a Program

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OPERATION GUIDE
Important notice
•Customers are advised to consult with Circuit Design sales representatives before ordering.
Circuit Design believes the provided information is accurate and reliable. However, Circuit Design reserves the
right to make changes to this product without notice.
•Circuit Design products are neither designed nor intended for use in life support applications where malfunction
can reasonably be expected to result in significant personal injury to the user. Any use of Circuit Design products
in such safety-critical applications is understood to be fully at the risk of the customer and the customer must fully
indemnify Circuit Design, Inc for any damages resulting from any improper use.
•As the radio module communicates using electronic radio waves, there are cases where transmission will be
temporarily cut off due to the surrounding environment and method of usage. The manufacturer is exempt from all
responsibility relating to resulting harm to personnel or equipment and other secondary damage.
•The manufacturer is exempt from all responsibility relating to secondary damage resulting from the operation,
performance and reliability of equipment connected to the radio module.
Copyright
•All rights in this operation guide are owned by Circuit Design, Inc. No part of this document may be copied or
distributed in part or in whole without the prior written consent of Circuit Design, Inc.
Cautions
•Do not use the equipment within the vicinity of devices that may malfunction as a result of electronic radio waves
from the radio module.
•Communication performance will be affected by the surrounding environment, so communication tests should be
carried out before actual use.
•Ensure that the power supply for the radio module is within the specified rating. Short circuits and reverse
connections may result in overheating and damage and must be avoided at all costs.
•Ensure that the power supply has been switched off before attempting any wiring work.
•The case is connected to the GND terminal of the internal circuit, so do not make contact between the '+' side of
the power supply terminal and the case.
•When batteries are used as the power source, avoid short circuits, recharging, dismantling, and pressure. Failure
to observe this caution may result in the outbreak of fire, overheating and damage to the equipment. Remove the
batteries when the equipment is not to be used for a long period of time. Failure to observe this caution may result
in battery leaks and damage to the equipment.
•Do not use this equipment in vehicles with the windows closed, in locations where it is subject to direct sunlight, or
in locations with extremely high humidity.
•The radio module is neither waterproof nor splash proof. Ensure that it is not splashed with soot or water. Do not
use the equipment if water or other foreign matter has entered the case.
•Do not drop the radio module or otherwise subject it to strong shocks.
•Do not subject the equipment to condensation (including moving it from cold locations to locations with a
significant increase in temperature.)
•Do not use the equipment in locations where it is likely to be affected by acid, alkalis, organic agents or corrosive
gas.
•Do not bend or break the antenna. Metallic objects placed in the vicinity of the antenna will have a great effect on
communication performance. As far as possible, ensure that the equipment is placed well away from metallic
objects.
•The GND for the radio module will also affect communication performance. If possible, ensure that the case GND
and the circuit GND are connected to a large GND pattern.
Warnings
•Do not take a part or modify the equipment.
•Do not remove the product label (the label attached to the upper surface of the module.) Using a module from
which the label has been removed is prohibited.
Copyright 2020, Circuit Design, Inc.

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OPERATION GUIDE
REVISION HISTORY
Version
Date
Description
Remark
1.0
Sep. 2020
MU4-RS2IF The first issue