Mitsubishi MELSEC-F FX-4AD User Manual

FX-4AD

SPECIAL FUNCTION BLOCK

USER'S GUIDE

JY992D52601E

This manual contains text, diagrams and explanations which will guide the reader in the correct installation
and operation of the FX-4AD special function block and should be read and understood before attempting
to install or use the unit.
Further information can be found in the FX PROGRAMMING MANUAL and FX SERIES HARDWARE
MANUAL.

1

●

The FX-4AD analog special function block has four input channels .The input channels receive
analog signals and convert them into a digital value.This is called an A/D conversion.The FX-4AD
has a maximum resolution of 12 bits.

●

The selection of voltage or current based input/output is by user wiring. Analog ranges of -10 to 10V
DC (resolution: 5mV), and/or 4 to 20mA, -20 to 20mA (resolution: 20µA) may be selected.

●

FX PC versions 2.0 or later (those with serial number 13OOOO or larger) are required as these
units have the TO/FROM applied instructions in their instruction set. Data transfer between the FX­4AD and the FX base unit is by buffer memory exchange. There are 32 buffer memories (each of
16 bits) in the FX-4AD.

●

The FX-4AD occupies 8 points of I/O on the FX, FX2C expansion bus. The 8 points can be allocated
from either inputs or outputs. The FX-4AD draws 30mA from the 5V rail of the FX base unit or
powered extension unit.

INTRODUCTION

1.1 External dimensions weight : Approx 0.5kg (1.1 lbs) Dimensions:mm (inches)

-

+

-

+

I+ FG

COM

V+

M3.5 (0.14")
terminal
screws

Extension
cable and
connector

+

+

DC24V

CH2

CH3

CH4

CH2 CH3

I+

I+

COMV+

COMV+

-

READYCH1

FG

FG

-

POWER

OFFSET

GAIN

I+

24V

A-D

I+ FG

V+ COM

CH1

35mm
(1.38in.)
DIN rail
mounting
slot

125
(4.92")

140
(5.51")

Mounting
holes

5.5mm

CH4

FG I+

COMV+

FG

COMV+

(0.27in.)
dia.

CH2 CH3

I+

V+

2

FG

V+COM

Voltage input
0 to +/-10V

*1 shielded

Current input
0 to +/-20mA

*1 shielded

DC24V

I+

COM

FG

50mA

*5

V+

10 (0.39")

I+

CH4

COM

FG

63 (2.48")
73 (2.87")

95 (3.74")

TERMINAL LAYOUTS

CH4

V

+

*2

I

+

COM

FG

CH1

V

+

I

+

*3

COM

FG

*4

DC24V

+

DC24V

-

100K

200K

AG(analog ground)

100K

250K

100K

100K

DC/DC

verter

con

AG

+15V

-15V

*1 The analog input is received through a twisted

pair shielded cable. This cable should be wired
separately from power lines or any other lines
which may induce electrical noise.

*2 If a voltage ripple occurs during input, or there is

electrically induced noise on the external wiring,
connect a smoothing capacitor of 0.1 to 0.47µF,
25V.

*3 If you are using current input, connect the V+ and

I+ terminals to each other.

*4 If there is excessive electrical noise, connect the

FG frame ground terminal with the grounded
terminal on the FX-4AD.

Class 3
Grounding

or less)

(100

PC

Extension cable

FX-4AD Analog Input Block

*5 Connect the ground terminal on the FX-4AD unit

with the grounded terminal on the base unit. Use
class 3 grounding on the base unit, if available.

3

INSTALLATION NOTES AND USAGE

3.1 General specification

Item Specification

General specifications(excluding withstand voltage) Same as those for the FX base unit

3.2 Power supply specification

Item Specification

Analog circuits 24V DC +/- 10%, 50mA(External power supply from base unit)

Digital circuits 5V DC, 30mA(Internal power supply from base unit)

3.3 Performance specifications

Analog inputs

Voltage input Current input

Item

Analog input range

Digital output

Resolution 5mV (10V default range 1/2000) 20µA(20mA default range 1/1000)
Overall accuracy +/-1% (for the range of -10V to +10V) +/-1% (for the range of -20mA to +20mA)
Conversion speed 15ms/channel (Normal speed), 6ms/channel (High speed)

Either voltage or current input can be selected with your choice of input terminal.
Up to four input points can be used at one time.

DC -10V to +10V (input resistance:200KΩ). DC -20mA to +20mA (input resistance:250Ω).
Warning:this unit may be damaged by input

voltage in excess of +/-15V.
12-bit conversion stored in 16-bit 2's complement form.

Maximum value:+2047 Minimum value:-2048

Warning:this unit may be damaged by input
currents in excess of +/-32mA.

Analog inputs continued.....

Preset 0 (-10V to +10V) Preset 1 (+4mA to +20mA) Preset 2 (-20mA to +20mA)

Digital
Output

-10.24V

-10V

+2047
+2000

+10V

-2000

-2048
Voltage Input

+10.235V

Digital
Output

+1750

+1000

+4
mA

+32

+20

mA

mA

Current
Input

Digital
Output

+1600
+1000

-20mA-32mA
+32mA+20mA

-1000

-1600
Current

Input

NOTE: Preset ranges are selected by an appropriate setting in buffer memory of the analog block.
Current/Voltage input selection must match the correct input terminal connections.

Miscellaneous

Item Specification

Photo-coupler isolation between analog and digital circuits.

Isolation

Number of occupied I/O points 8 points taken from the FX expansion bus (can be either inputs or outputs)

DC/DC converter isolation of power from FX base unit.

No isolation between analog channels.

3.4 Allocation of buffer memories (BFM)

BFM Contents

*# 0 Channel initialization Default = H0000
*# 1 Channel 1
*# 2 Channel 2
*# 3 Channel 3
*# 4 Channel 4
# 5 Channel 1
# 6 Channel 2
# 7 Channel 3
# 8 Channel 4

# 9 Channel 1
#10 Channel 2
#11 Channel 3
#12 Channel 4

#13-#14 Reserved

Selection of A-D

#15

#16-#19 Reserved

conversion
speed see note 2

Contains the number of samples (1 to 4096) to
be used for an averaged result. The default
setting for normal speed is 8.
The default setting for high speed is 1.

These buffer memories contain the averaged
input values for the number of samples entered
for the channel in buffer memories #1 to #4
respectively.

These buffer memories contain the present
value currently being read by each input
channel.

When set to 0, a normal speed is selected of
15ms/ch (default)

When set to 1, a high speed is selected of
6ms/ch

In buffer memory locations (BFMs) marked
with an "*" data can be written from the PC
using the TO command.

For buffer memories (BFMs) without the "*"
mark, data can be read to the PC using the
FROM command.

Before reading from the analog special
function block, ensure these settings have
been sent to the analog special function
block. Otherwise, the previous values held
in the analog block will be used.

BFM b7 b6 b5 b4 b3 b2 b1 b0
*#20 Reset to Defaults and Preset. Default=0
*#21 Offset, Gain Adjust Prohibit. Default=(0,1)Permit
*#22 Offset, Gain Adjust
*#23 Offset Value Default=0

*#24 Gain Value Default=5,000

#25-#28 Reserved

#29 Error status
#30 Identification code K2010
#31 Cannot be used

G4 O4 G3 O3 G2 O2 G1 O1

The buffer memory also gives a facility to
adjust offset and gain by software as well
as by panel switches of the FX-4AD unit.
(see note 3)

Offset (intercept): The analog input value
when the digital output becomes 0.

Gain (slope): The analog input value when
the digital output becomes +1000.

(1) Channel Selection

Channel initialization is made by a 4 character HEX number HOOOO in buffer memory BFM #0.
The least significant character controls channel 1 and the 4 character controls channel 4.
Setting of each character is as follows:
O = 0: Preset range (-10V to +10V) O = 2: Preset range (-20mA to +20mA)
O = 1: Preset range (+ 4mA to + 20 mA) O = 3: Channel OFF

Example: H3310
CH1: preset range (-10V to +10V)
CH2: preset range (+ 4mA to +20mA)
CH3, CH4: Channel OFF

(2) Analog to Digital Conversion Speed Change

By writing 0 or 1 into BFM #15 of the FX-4AD, the speed at which A-D conversion is performed can be
changed. However the following points should be noted:
To maintain a high speed conversion rate, use the FROM/TO commands as seldom as possible.

NOTES: When a conversion speed change is made, BFM #1-#4 are set to their default values immediately

after the change.
This is regardless of the values they held originally. Bear this in mind if a speed change will be
made as part of the normal program execution.

(3) Adjusting Gain and Offset Values

When buffer memory BFM #20 is activated by setting it to K1, all settings within the analog special

(a)

function block are reset to their default settings. This is a very quick method to erase any undesired
gain and offset adjustments.

If (b1, b0) of BFM #21 is set to (1,0), gain and offset adjustments are prohibited to prevent inadvertent

(b)

changes by the operator. In order to adjust the gain and offset values, bits (b1, b0) must be set to
(0,1). The default is (0,1).

Gain and offset values of BFM #23 and #24 are sent to non-volatile memory gain and offset registers

(c)

of the specified input channels. Input channels to be adjusted are specified by the appropriate G-O
(gain-offset) bits of BFM #22 Example: If bits G1 and O1 are set to 1, input channel 1 will be
adjusted when BFM #22 is written to by a TO instruction.

Channels can be adjusted individually or together with the same gain and offset values.

(d)

Gain and offset values in BFM #23 #24 are in units of mV or µA. Due to the resolution of the unit the

(e)

actual response will be in steps of 5mV or 20µA.

(4) Status information BFM #29

Bit ON OFF

When any of b1 to b4 is ON.

b 0:Error

b 1:Offset/Gain error
b 2:Power source abnormality DC 24V power supply failure Power supply normal

b 3:Hardware error A/D converter or other hardware failure Hardware normal
b 8:Not READY FX-4AD MODE switch is not set to READY READY mode

b10:Digital range error

b11:Averaging error

b12: Offset/Gain adjust prohibit Prohibit-(b1,b0) of BFM #21 is set to (1,0) Permit-(b1,b0) of BFM #21 is set to (0,1)

If any of b2 to b4 is ON,A/D conversion

of all the channels is stopped

Offset/Gain data in EEPROM is corrupted

or adjustment error.

Digital output value is less than -2048

or more than +2047

Number of averaging samples is 4097 or

more or 0 or less

(default of 8 will be used)

No error

Offset/Gain data normal

Digital output value is normal

Averaging is normal (between 1 and 4096)

NOTE : • b4 to b7,b9 and b13 to b15 are undefined.

(5) Identification code BFM #30

The identification (or ID) code number for a Special Function Block is read using the FROM command.
The code for the FX-4AD unit is K2010.
The user's program in the PC can use this facility in the program to identify the special function block

before commencing data transfer from and to the special function block.

CAUTION

●

Values of BFM #0, #23 and #24 are copied to EEPROM memory of the FX-4AD. BFM #21 and

BFM #22 are only copied when data is written to the gain/offset command buffer BFM #22. Also,
BFM #20 causes writing to the EEPROM memory. The EEPROM has a life of about 10,000 cycles
(changes), so do not use programs which frequently change these BFMs.

●

Because of the time needed to write to the EEPROM memory, a delay of 300 ms is required

between instructions that cause a write to the EEPROM.

Therefore, a delay timer should be used before writing to the EEPROM a second time.

4

DEFINING GAIN AND OFFSET

(a)

(b)

1000

Digital

Gain value

Analog

Gain determines the angle or slope of the calibration line,
identified at a digital value of 1000.
(a) Small gain-- Large steps in digital readings
(b) Zero gain --- default : 5V or 20mA
(c) Large gain - Small steps in digital readings

(c)

OffsetGain

Digital

0

Analog

Offset is the 'Position' of the calibrated line, identified at a
digital value of 0.
(d) Negative offset
(e) Zero offset - default : 0V or 4mA
( ) Positive offset

f

(f)(e)(d)

Offset value

Offset and gain can be set independently or together. Reasonable offset ranges are -5 to +5V or -20mA to
20mA, and gain values 1V to 15V or 4mA to 32mA. Gain and offset can be adjusted by software in the FX base
unit (see program example 2) or by the switches on the FX-4AD (with the aid of a voltmeter/ammeter)

●

Bit device's b1, b2 of the gain/offset BFM #21 should be set to 0, 1 to allow adjustment.

●

Once adjustment is complete these bit devices should be set to 1, 0 to prohibit any further changes.

●

Channel initialization (BFM #0) should be set to the nearest range, i. e. voltage/current etc.

1.

Power the system up (the FX base unit can be in either RUN or STOP mode).

2.

Set the FX-4AD MODE switch to the first channel number.

3.

Apply the offset analog input to the terminal of the channel.

4.

Press the OFFSET button once. The digital offset value (converted from the analog input value) is
stored in the FX-4AD.

5.

Apply the gain analog input to the input terminal of the channel to be adjusted.

6.

Press the GAIN button once. The digital gain value is stored in the FX-4AD.

7.

Repeat operations 3 to 6 for each channel you wish to use.

8.

Set the FX-4AD MODE switch to READY to complete gain and offset adjustment.

NOTE:

If the MODE switch is not set to a channel number, the FX-4AD is regarded as being in the READY
status and no adjustments can be made.

5

EXAMPLE PROGRAM

5.1 Basic program

In the following example channels CH1 and CH2 are used as voltage inputs. The FX-4AD block is connected
at the position of special function block No.0. Averaging is set at 4 and data registers D0 and D1 of the PC
receive the averaged digital data.

M8002

Initial
pulse

M1

FROM

TO P

TO

FROM

K0 K30 D4 K1

CMP

K2010 D4 M0

K0

K0

K0 K29 K4M10 K1

K0 H3300 K1

K1 K4 K2

The ID code for the special function block at position
"0" is read from BFM #30 of that block and stored at
D4 in the base unit. This is compared to check the
block is an FX-4AD, if OK M1 is turned ON. These
two program steps are not strictly needed to perform
an analog read. They are however a useful check
and are recommended as good practise.

The analog input channels (CH1, CH2) are setup by
writing H3300 to BFM #0 of the FX-4AD.

The number of averaged samples for CH1 and CH2
is set to 4 by writing 4 to BFM #1 and #2 respectively.
Do not execute the pulse.

The operational status of the FX-4AD is read from
BFM #29 and output as bit devices at the FX base
unit.

M18M10

FROM

NO

READY

error

K0

K5 D0 K2

If there are no errors in the operation of the FX-4AD,
then the averaged data BFM's are read.
In the case of this example BFM #5 and #6 are read
into the FX base unit and stored at D0 and D1. These
devices contain the averaged data for CH1 and CH2
respectively.

5.2 Using gain and offset in a program

The gain and offset of the FX-4AD can be adjusted using push-button switches on the input terminal of the PC.
It can also be adjusted using software settings sent from the PC.

Only the gain and offset values in the memory of the FX-4AD need be adjusted. A voltmeter or an ammeter
for the analog input is not needed. A program for the PC will be needed however.

The following is an example of changing the offset value on input channel CH1 to 0V and the gain value to 2.5V.
The FX-4AD block is in the position of block No.0 (i.e. closest to the FX base unit).

Example: Adjusting gain/offset via software settings

X010

SET M0

• Adjustment start.

M0

T0

T1

TO P K0 K0 H0000 K1

TO P K0 K1 K1K21

TO K0 K0K22

TO P K0 K23 K0 K1

TO P K0 K2500 K1K24

TO P K0 H0003 K1K22

RST M0

K1

T0

T1

• (H0000) → BFM #0 (initialize input channels)
Enter the instructions on the left and RUN the PC with
the MODE switch of the FX-4AD set to READY.

• (K1) → BFM #21

BFM #21 (gain/offset adjust prohibit) must be set to
permit with (b1, b0) = (0,1).

• (K0) → BFM #22 (offset/gain adjust)

Reset adjust bits.

K4

• (K0) → BFM #23 (offset)

• (K2500) → BFM #24 (gain)

• (H0003) → BFM #22 (offset/gain adjust)

3 = 0011 i.e. O1 = 1, G1 = 1.
Therefore channel 1 is adjusted.

K4

• Adjustment end.

TO P

K0

K21 K2 K1

• (K2) → BFM #21

BFM #21 gain/offset adjust prohibit.

6

DIAGNOSTICS

6.1 Preliminary checks

Check whether the input wiring and/or expansion cables are properly connected on FX-4AD analog

I

special function block.
Check that the FX system configuration rules have not been broken, i.e. the number of blocks does

II

not exceed 8 and the total system I/O is equal or less than 256 I/O.

III

Ensure that the correct operating range has been selected for the application.

IV

Check that the MODE switch on the FX-4AD panel is set to the READY position.

V

Check that there is no power overload on either the 5V or 24V power source, remember the loading
on a FX base unit or a powered extension unit varies according the number of extension block or
special function blocks connected.

VI

Put the FX base unit into RUN.

6.2 Error checking

If the FX-4AD special function block does not seem to operate normally, check the following items.

●

Check the status of the POWER LED.
Lit : The extension cable is properly connected.
Otherwise: Check the connection of the extension cable.

●

Check the external wiring.

●

Check the status of "24V" LED (top right cover of the FX-4AD).
Lit: FX-4AD is OK, 24V DC power source is OK.
Otherwise: Possible 24V DC power failure, if OK then possible FX-4AD failure.

●

Check the status of the "A/D" LED (top right cover of the FX-4AD)
Lit: A/D conversion is proceeding normally
Otherwise: Check buffer memory #29 (error status). If any bits (b2 and b3) are ON, then this is why
the A/D LED is OFF.

Guidelines for the safety of the user and protection of
the FX-4AD special function block

●

This manual has been written to be used by trained and competent personnel. This is defined
by the European directives for machinery, low voltage and EMC.

●

If in doubt at any stage during the installation of the FX-4AD always consult a professional
electrical engineer who is qualified and trained to the local and national standards. If in doubt
about the operation or use of the FX-4AD please consult the nearest Mitsubishi Electric distributor.

●

Under no circumstances will Mitsubishi Electric be liable or responsible for any consequential
damage that may arise as a result of the installation or use of this equipment.

●

All examples and diagrams shown in this manual are intended only as an aid to understanding
the text, not to guarantee operation. Mitsubishi Electric will accept no responsibility for actual
use of the product based on these illustrative examples.

JY992D52601E

Manual number : JY992D52601
Manual revision : E
Data : APRIL 1998

HEAD OFFICE : MITSUBISHI DENKI BLDG MARUNOUCH TOKYO 100 TELEX : J24532 CABLE MELCO TOKYO
HIMEJI WORKS : 840, CHIYODA CHO, HIMEJI, JAPAN

Effective APR. 1998
Specifications are subject
to change without notice.