Amada MH-P20B-2 Series User manual

AA05OM1208811-05
OPERATION MANUAL
MOTOR-DRIVEN RESISTANCE WELDING HEAD
MH-P20B-2 □
MH-D20B-2 □

MH-P20B-2□/MH-D20B-2□
1
Thank you for purchasing our Motor-Driven Resistance Welding Head MH-P20B-2□/
D20B-2□.
・This operation manual explains its method of operation and precautions for use.
・Before using, read this operation manual carefully; after reading, save it in a proper place
where you can easily access.
Contents
1. Special Precautions
(1) Safety Precautions.................................................................... 1-1
(2) Precautions for Handling ........................................................... 1-4
(3) On Disposal .............................................................................. 1-4
2. Features....................................................................................... 2-1
3. Name and Functions of Each Section
(1) MH-P20B .................................................................................. 3-1
(2) MH-D20B .................................................................................. 3-3
(3) Controller Front ......................................................................... 3-5
(4) Controller Rear.......................................................................... 3-7
4. Interface
(1) Connection Diagram of External Input/Output Signal ................ 4-1
(2) I/O Connector............................................................................ 4-3
5. Installation and Connection........................................................ 5-1
6. Operation
(1) Getting Started.......................................................................... 6-1
(2) Mode Setting............................................................................. 6-2
(3) Applying Power and Moving to Start Point................................. 6-3
(4) Auto-Setting of Electrode Position............................................. 6-4
(5) Manual Setting of Electrode Position......................................... 6-5
(6) Welding Work............................................................................ 6-10
(7) Measuring Weld Force .............................................................. 6-11
7. Fault Indications .......................................................................... 7-1
8. User’s Maintenance
(1) MH-P20B .................................................................................. 8-1
(2) MH-D20B .................................................................................. 8-4
9. Specifications
(1) Product Specifications............................................................... 9-1
(2) Accessories............................................................................... 9-1
(3) Timing Chart ............................................................................. 9-2
(4) Separately Sold Items ............................................................... 9-2
10. Data Communication
(1) Communication Specifications .................................................. 10-1
(2) Connection of Communication Connector ................................. 10-1
(3) Bidirectional Communication..................................................... 10-3
11. Outline Drawings
(1) MH-P20B-20/-21 Head.............................................................. 11-1
(2) MH-D20B-20 Head.................................................................... 11-2
(3) Head Controller......................................................................... 11-3

MH-P20B-2□/MH-D20B-2□
1. Special Precautions
1-1
1. Special Precautions
(1) Safety Precautions
Before using, read "Safety Precautions"
carefully to understand the correct method
of use.
■These precautions are shown for safe use
of our products and for prevention of
damage or injury to operators or others.
Be sure to read each of them, since all of
them are important for safety.
■The meaning of the words and symbols is
as follows.
These symbols denote
"prohibition".
They are warnings about
actions out of the scope of the
warranty of the product.
These symbols denote actions
which operators must take.
Each symbol with a triangle
denotes that the content gives
notice of DANGER, WARNING
or CAUTION to the operator.
Denotes operations and practices that
may imminently result in serious injury
or loss of life if not correctly followed.
Denotes operations and practices that
may result in serious injury or loss of
life if not correctly followed.
Denotes operations and practices that
may result in personal injury or damage
to the equipment if not correctly followed.
Never disassemble, repair or modify the Welding Head
These actions can cause electric shock and fire. Do not do anything other than
the maintenance described in the operation manual.
Never burn, destroy, cut, crush or chemically decompose the Welding Head
This product incorporates parts containing gallium arsenide (GaAs).
DANGER
！
W
ARNING
！
CAUTION
！
DANGER
！

MH-P20B-2□/MH-D20B-2□
1. Special Precautions
1-2
Do not put your hands between the electrodes
When welding, keep your fingers and hands away from the electrodes.
Do not touch any welded part or electrodes during welding and just after
welding finished
The welded part of a workpiece, electrodes and electrode holder are very hot.
Do not touch them; otherwise you may be burnt.
Apply the specified power supply
Application of a voltage out of the specified range can cause fire and electric
shock.
Stop the operation if any trouble occurs
Continuous operation after occurrence of a trouble such as burning smell,
abnormal sound, abnormal heat, smoke, etc. can cause electric shock and fire.
If such a trouble occurs, immediately consult us or your distributor.
Persons with pacemakers must stay clear of the welding machine
A person who uses a pacemaker must not approach the welding machine or
walk around the welding shop while the welding machine is in operation, without
being permitted by his/her doctor. The welding machine generates a magnetic
field and has effects on the operation of the pacemaker while it is turned on.
Wear protective glasses
If you look at the surface flash and expulsion directly during welding, your eyes
may be damaged.
W
A
RNING
！

MH-P20B-2□/MH-D20B-2□
1. Special Precautions
1-3
Do not splash water on the Welding Head
Water splashed over the ele
ctric parts can cause electric shock and short
circuits.
Use proper tools (wire strippers, pressure wire connectors, etc) for
termination of the connecting cables
Do not cut the conductor of wire. A flaw on it can cause fire and electric shock.
Do not damage the power cable and connecting cables
Do not tread on, twist or tense any cable. The power cable and connecting
cables may be broken, and that can cause electric shock and fire.
When you need any repair or replacement, consult us or your distributor.
Connect the specified cables securely
Cables of insufficient current-
carrying capacities and loose connections can
cause fire and electric shock.
Install the Welding Head on firm, level surface
If the Welding Head falls or drops, injury may result.
Keep combustible matter away from the welding machine
Surface flash and expulsion can ignite combustible matter. If it is impossible to
remove all combustible matter, cover them with non-combustible material.
Do not cover the Welding Head with a blanket, cloth, etc.
If such a cover is used, it may be heated and burn.
Keep a fire extinguisher nearby
Keep a fire extinguisher in the welding shop in case of fire.
Maintain and inspect the Welding Head periodically
Maintain and inspect the Welding Head periodically, and repair any damage
nearby before starting operation.
Protective gear must be worn
Put on protective gear such as protective gloves, long-sleeve jacket, leather
apron, etc. Surface flash and expulsion can burn the skin if they touch the skin.
Do not use this Welding Head for purposes other than welding
Use of this Welding Head in a manner other than specified can cause electric
shock and fire.
CA
UTION
！

MH-P20B-2□/MH-D20B-2□
1. Special Precautions
1-4
(2) Precautions for Handling
■Do not install this Welding Head in the following:
・Damp places where humidity is higher than 90%,
・Dusty places,
・Places where chemicals are handled,
・Places near a high noise source,
・Hot or cold places where temperatures are above 40°C or below 0°C, and
・Places where water will be condensed.
■Clean the outside of the Welding Head with a soft, dry cloth or one wet with a
little water. If it is very dirty, use diluted neutral detergent or alcohol. Do not use
paint thinner, benzine, etc., since they can discolor or deform the Welding Head.
■Do not put anything other than a workpiece, e.g., a tool, a screw, etc., between
the electrodes. It can cause serious trouble.
■Do not put a screw, a coin, etc., in the Welding Head, since they can cause a
malfunction.
■Operate the Welding Head according to the method described in this operation
manual.
■Operate the button carefully by hand. If it is operated roughly or with the tip of a
screwdriver, a pen, etc., this will cause malfunction or damage.
■Since power supply to the motor is cut off at power off or emergency stop, the
force follow-up mechanism may lower to the maximum stroke position by its
own weight.
(3) On Disposal
This product incorporates parts containing gallium arsenide (GaAs). At the time of
disposal, separate it from general industrial waste or domestic waste and carry out
the disposal in accordance with applicable laws and regulations.

MH-P20B-2□/MH-D20B-2□
2. Features
2-1
2. Features
Owing to motor-driven mechanism, stable electrode force is always obtained even if
the electrode opening changes. Also, you don’t need to adjust the electrode opening
finely when replacing electrode.
The electrode force is 5 to 35
N (0.5 to 3.5 kgf) per electrode on MH-P20B, and
10 to 70
N (1 to 7 kgf) on MH-D20B.
You can fit the electrode-force speed to suit your welding work as it is adjustable in
four steps; the electrode-up/down speed, in eight steps.
Thirty-one welding schedules are selectable; they are selectable externally.
The electrode moves down fast from the start point (stand-by position) to the mid-point
(middle-stop position); then slowly to contact the workpiece.
Very little shock deforms the workpieces less and extends the electrode life.
The start point and the mid-point are adjustable arbitrarily.
The electrode moves up and down between the mid-point and workpiece for
continuous welding. This reduces the weld cycle time as the electrode doesn’t need to
return to the start point every time it welds.
During welding, the workpieces expands and shrinks. This Welding Head employs a
spring so that the electrode can follow-up the deformation of the workpiece fast, which
reduces the surface flash.
The dedicated controller easily sets the electrode position and speed.
Since this Welding Head is motor driven, the piping for air actuation is not needed,
enabling an easy installation.

MH-P20B-2□/MH-D20B-2□
3. Name and Functions of Each Section
3-1
3. Name and Functions of Each Section
(1) MH-P20B
0
1
2
0
1
2
10
11211
2
3
4
5 6
9
8
7
①Weld Force Adjustment Knob
Adjusts the electrode force.
②Lock Screw
Locks the Weld Force Adjustment Knob.

MH-P20B-2□/MH-D20B-2□
3. Name and Functions of Each Section
3-2
③Holder
For fixing the Electrode Holder (sold separately).
④Body-Fixing Screw (M6)
Secures the Head body to the Column.
⑤Holder-Mounting Screw (M4)
Mounts the Electrode Holder (sold separately) to the Holder.
⑥Volt-Sensing-Cable-Connecting Screw
Connects the Volt-Sensing Cable (sold separately).
⑦Secondary-Cable-Fixing Screw (M8)
Connects the Secondary Cable.
⑧Column
For mounting the Head body.
⑨Base
For the Welding Head.
⑩Base-Mounting Holes
For mounting the Welding Head to the workbench. Six (6) holes are provided.
φ6.5
mm diameter, φ11 mm spot facing and 10 mm depth.
⑪Maximum-Weld-Force-Indicating Label
Indicates the maximum electrode force (See p. 8-3).
⑫Weld Force Conversion Graph
Shows an approximate electrode force for your weld force adjustment.
ATTENTION
Should a metal object, such as a screwdriver and wire, contact the Holder
during operation, the object may be welded to the Welding Head. Before
starting work, be sure to remove all metal objects from around the equipment.

MH-P20B-2□/MH-D20B-2□
3. Name and Functions of Each Section
3-3
(2) MH-D20B
0
1
2
2
1
3
4
5
6
78 9
10 11
12
13
①Weld Force Adjustment Knob
Adjusts the electrode force.
②Lock Screw
Locks the Weld Force Adjustment Knob.
③Weld Force Conversion Graph
Shows an approximate electrode force for your weld force adjustment.
④Electrode
For spot welding. Material is CrCu.

MH-P20B-2□/MH-D20B-2□
3. Name and Functions of Each Section
3-4
⑤Electrode Holder
Clamps the Electrode.
⑥Electrode-Fixing Screw (M4)
Secures the Electrode to the Electrode Holder.
⑦Holder-Mounting Screw (M4)
Mounts the Electrode Holder to the Holder.
⑧Volt-Sensing-Cable-Connecting Screw
Connects the Volt-Sensing Cable (sold separately).
⑨Secondary-Cable-Fixing Screw (M6)
Connects the Secondary Cable.
⑩Holder
For fixing the Electrode Holder. Two Holders are provided for the upper electrode
and the lower one.
⑪Base
For the Welding Head.
⑫Head-Fixing Bracket
For fixing the Welding Head to the workbench. Two (2) brackets provided.
φ5.5
mm mounting hole diameter (M5 countersink).
⑬Holder-Fixing Screw (M5)
For fixing the lower Holder to the Base.
ATTENTION
Should a metal object, such as a screwdriver and wire, contact the Electrode
or the Electrode Holder during operation, the object may be welded to the
Welding Head. Before starting work, be sure to remove all metal objects from
around the equipment.
ATTENTION
Should a metal object, such as a screwdriver and wire, contact the Holder
during operation, the object may be welded to the Welding Head. Before
starting work, be sure to remove all metal objects from around the equipment.

MH-P20B-2□/MH-D20B-2□
3. Name and Functions of Each Section
3-5
(3) Controller Front Panel
Operation Button
Operate the Welding Head by turning
the button clockwise/counterclockwise
or pressing it.
By turning the button, the lamp
illumination changes as shown:
See the list below for to ⑪
Lamp
When illuminated,
When blinking,

[SCH
(Schedule)]
Display
Schedule Nos. are displayed.
(31 c
ombinations of Electrode position,
Speed and Hold Time can be registered
as Schedule in the model of
MH-P20B/D20B.)
When power supply
is applied,
zero “0” blinks.
When trouble occurs, fault code
is displayed.
Schedule No. is being changed.
Weld force is being measured.

[SCH] Lamp
Operation button is selecting a function. Schedule No. is being changed.

[READY]
Lamp
Electrode is at Start Point and completed
for work. Start Point is being changed.
Operation button is selecting a function.

[MID] Lamp
Electrode is at Mid-Point. Mid-Point is being changed.
Operation button is selecting a function.

[Weld] Lamp
Electrode is at Weld Point. Lowest point (Downstop Point) is
being changed.
Operation button is selecting a function.

[Hold] Lamp
Operation button is selecting a function. Hold Time is being changed.

[AUTO] Lamp
Operation button is selecting a function. Auto-function is setting elec-
trode position and movement.
[FORCE CHK]
Lamp
Operation button is selecting a function. Weld force is being measured.
[TROUBLE]
Lamp
Trouble is occurring.
⑪
[ORG] Lamp
The [ORG] Lamp is in no use.
READY
READY＋MID
SCH
FORCE CHK
WELD
AUTO
HOLD
MID＋WELD
MID＋WELD
+FORCE CHK
MID
WELD＋HOLD
ORG/CANCEL
MID
HOLD
TROUBLE
READY
SCH
WELD
ORG
FORCE
CHECK
AUTO
SPEED
HOLD
TIME
W E L D H E A D
C O N T R OL U N I T
1
12
2
3
4
5
6
7
8
9
10
11
13
⑭

MH-P20B-2□/MH-D20B-2□
3. Name and Functions of Each Section
3-6
⑫[SPEED HOLD TIME] Display
Indicate the “electrode speed” and “HOLD Time after the application of weld force
is completed”. The larger number indicates the faster electrode speed and the
longer HOLD Time.
And the lamp lights up simultaneously with other lamps as follows:
Lamp When illuminated, When blinking,

[READY] Lamp
and

[MID] Lamp
and
⑫
[SPEED
HOLD TIME]
Display
Operation button is selecting a function.
([SPEED HOLD TIME] Display does
not light up.)
Electrode speed between
Start Point and Mid-Point is
being set.
Electrode
is moving between Start
Point and Mid-Point.

[MID] Lamp
and

[WELD] Lamp
and
⑫
[SPEED
HOLD TIME]
Display
Operation button is selecting a function.
([SPEED HOLD TIME] Display does
not light up.) Electrode speed from Weld
Point to Mid-
Point is being
set.
Electrode is moving from Weld Point to
Mid-Point.

[MID] Lamp
and

[WELD] Lamp
and

[FORCE CHK]
Lamp and
⑫
[SPEED
HOLD TIME]
Display
Operation button is selecting a function.
([SPEED HOLD TIME] Display does
not light up.)
Electrode speed from
Mid-
Point to Weld Point is
being set.
Electrode is moving from Mid-
Point to
Weld Point.
([FORCE CHK] Lamp does not light up
during movement.)
[WELD] Lamp
and

[HOLD] Lamp
and
⑫
[SPEED
HOLD TIME]
Display
Operation button is selecting a function.
([SPEED HOLD TIME] Display does
not light up.)
The desired time for which
the additional weld force is
exerted on after applying
the weld force at Weld Point
is being set.
[HOLD] Lamp
and
⑫
[SPEED
HOLD TIME]
Display
Operation button is selecting a function.
([SPEED HOLD TIME] Display does
not light up.)Hold Time is being set.
⑫
[SPEED
HOLD TIME]
Display
In case of Movement Mode 1, electrode
position is at Start Point and the
Display shows “A” when setting is not
performed.
⑬[ORG/CANCEL] Button
The Button interrupts the operation of setting.
⑭Communication Connector (D-Sub, 25 pins)
For data communication with the external device.

MH-P20B-2□/MH-D20B-2□
3. Name and Functions of Each Section
3-7
(4) Controller Rear Panel
[MOTOR CONTROL] Connector
It is a connector for controlling a
motor to drive the electrode.
I/O Connector
It is for input/output of signals.
Connector for Weld Force
Detecting Sensor
It is for inputting the weld force signal
of the welding head.
Power Switch
It is a switch for turning on/off power
supply of 100 to 240
V AC.
Fuse Holder
It contains a fuse.
Fuse Rating 250
V, 1 A, 5 mm dia. 20 mm length (Delay melting
and high breaking capacity type)
Connector for Power Supply Cable
It is for connecting a power supply cable (separately sold) of power supply of 100
to 240
V AC.
Ground Terminal
Use the ground terminal when you can not take a ground by using a power supply
cable with a ground wire (separately sold).
1
2
3
4
5
6
7

MH-P20B-2□/MH-D20B-2□
4. Interface
4-1
4. Interface
(1) Connection Diagram of External Input/Output Signal
24VDC
READY
START POINT
MID POINT
OUT COM
ERROR
OUT COM
-COM
RY STOP
+COM
SCH1
SCH2
SCH4
SCH8
SCH16
+COM
-COM
-COM
WELD START
-COM
EXT.C O M
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
2ND
1ST
+COM
END
ORG
RESET
P.LOC K
Å
External Input/Output Connector
Motor Head Controller
Spare: Do not connect
Spare: Do not connect
Spare: Do not connect
EXT.24V: Do not connect
Spare: Do not connect

MH-P20B-2□/MH-D20B-2□
4. Interface
4-2
[Example of Connection]
・When contacts are used as input terminal of I/O connector
・When NPN transistor (sink type) on PLC is used as input terminal of I/O connector
・When PNP transistor (source type) on PLC is used as input terminal of I/O
connector
1ST
2ND
-COM
+COM
EXT. C OM
+COM
8
9
10
11
12
13
14
15
-COM
24VDC
Å
8
9
10
11
12
13
14
15
PLC
+24V
24VDC
Å
1ST
2ND
-COM
+COM
EXT. COM
+COM
8
9
10
11
12
13
14
15
-COM
24VDC
Å

MH-P20B-2□/MH-D20B-2□
4. Interface
4-3
(2) I/O Connector
Each pin on I/O Connector is described.
Input signal is explained as contact input.
Pin
No.
I/O Description
1 Internally connected to GND (0V).
2
Input
Select a schedule number, referred to as SCH No. below, indicating a
combination of the circuit-closed pins among Pins, No. 2, 3, 4, 5 and 6
(See table below.).
The schedule number selected by I/O Connector has priority over the
schedule number set on MH-P20B/D20B. Before selecting the schedule
number by the operation button on MH-P20B/D20B, open the circuits of
all the Pins of No. 2, 3, 4, 5 and 6 in I/O Connector.
Input [SCH] signal at least 2
ms before the welding current flows. During
in operation, the schedule number cannot be changed.
3
4
5
6
Pin No.
SCH No.
6 5 4 3 2
Pin No.
SCH No.
6 5 4 3 2
1
●
17
● ●
2
●
18
● ●
3
● ●
19
● ● ●
4
●
20
● ●
5
● ●
21
● ● ●
6
● ●
22
● ● ●
7
● ● ●
23
● ● ● ●
8
●
24
● ●
9
● ●
25
● ● ●
10
● ●
26
● ● ●
11
● ● ●
27
● ● ● ●
12
● ●
28
● ● ●
13
● ● ●
29
● ● ● ●
14
● ● ●
30
● ● ● ●
15
● ● ● ●
31
● ● ● ● ●
16
●
The mark ●denotes the circuit-closed pin.

MH-P20B-2□/MH-D20B-2□
4. Interface
4-4
Pin
No.
I/O Description
7 Output pins for 24 V DC through 100Ωinternal resistor.
8
9
Input
Input pin for start-up signal.
When [1ST] is closed, electrode moves from Start Point to Mid-Point.
When [2ND] is closed after [1ST] was c
losed, electrode moves from
Mid-Point to Weld Point.
Although only [2ND] is closed, electrode does not move.
10
11 Spare pin: Do not connect.
12 Connected to [GND] (0V) internally at factory shipment.
13 Output pins for 24 V DC through 100Ωinternal resistor.
14
According to the usage, connect pins as follows.
・
When contact is used as input signal of I/O Connector, connect Pins
14 and 15.
・
When NPN transistor (sink type) on PLC is used as input signal of I/O
Connector, connect Pins 13 and 14. COM terminal of PLC connects
to ―COM terminal, that is, Pins 1, 12 and 15.
・
When PNP transistor (source type) on PLC is used as input signal of
I/O connector, connect Pin 14 to COM terminal of PLC.
15 Connected to [GND] (0V) internally at factory shipment.
16 Input Input pin for [End] signal from welding power supply.
If Pin 16 is closed, input signal of [2ND] cannot be accepted.
14
15
EXT.COM
-COM
13
14 EXT.COM
+COM
EXT.COM
14 PLC Output
Terminal COM

MH-P20B-2□/MH-D20B-2□
4. Interface
4-5
Pin
No.
I/O Description
17
Input
Input pin for Start Point resuming signal.
When the circuit of Pin 17 becomes closed, the electrode resumes Start
Point. (In case that the motor finishes moving back to Original Point, the
electrode does not move.)
18
Input pin for [RESET] signal.
If a trouble occurs, rectify the trouble and close the circuit of the Pin to
turn off [NG] signal. (See Chapter 7 for fault codes.)
Close at least for 2 ms. Pin 18 does not work while the circuit of Pin 18
is closed.
19
Input pin for prohibition of setting the operation schedule.
When Pin 19 is closed, the operation schedule of MH-P20B/D20B
cannot be set. (The schedule number can be modified.)
20 Spare pin: Do not connect.
21
Output
Output pin for an emergency stop of the motor.
When the circuit between Pins 21 and 22 is opened, the motor carries
out emergency stop.
Connect the operation switch for an emergency stop of the motor to
Pins 21 and 22 of the I/O connector. Use the operation switch whose
capacity is more than 24
V DC, 20 mA.
Since power supply to the motor is cut off, the force follow-up
mechanism may lower to the maximum stroke position
by its own
weight.
22
23 Output pin for current-supplying
start signal to the welding power
supply.
When the weld force is completed, the circuit between Pins 23 and 24
becomes closed.
Contact capacity is 24
V DC, 20 mA.
24
25
Output pin for completion signal of
being ready for work.
When the resumption of Start Point is
completed, the Pin becomes closed. In
an emergency of MH-P20B/D20B, the
Pin becomes opened.
26
Output pin for completion signal of
arriving at Start Point.
When the electrode is at Start Point,
the Pin becomes closed.
27
Output pin for completion signal of
arriving at Mid-Point.
When the electrode is at Mid-Point, the
Pin becomes closed.
25 READY
OUT COM28
or 31
OUT COM28
or 31
26 START POINT
OUT COM28
or 31
27 MID POINT

MH-P20B-2□/MH-D20B-2□
4. Interface
4-6
Pin
No.
I/O Description
28 Common terminal to [
READY], [START POINT], [MID POINT] and
[ERROR]
29 Output
Output pin for a trouble signal.
When a trouble occurs in
MH-P20B/D20B, the Pin
becomes opened until it is reset.
30 Spare pin: Do not connect.
31 Common terminal to [READY], [START POINT], [M
ID POINT] and
[ERROR]
32 Do not connect to the Pin for [EXT. 24 V].
33 Connected to [GND] (0 V) internally at factory shipment.
34 Spare pin: Do not connect.
OUT COM28
or 31
29 ERROR