|
| |
| ..... |
About TFML
In addition to the normal range of functions incorporated within the
MEDACS instruments, there is the ability to program the software in
order to customize its function. The normal operation of a standard
transmitter is as indicated below. The electrical input is processed
to linearize and condition the sensor value. The value is used to
create an output. The relationship between process input and output is
referred to as the transfer function. In this case it is a simple
relationship but more complex relationships are often required. |
| ..... |
|
INPUT
PROCESSING
|
> TO >
|
OUTPUT
PROCESSING
|
| ..... |
| If the relationship between input and output can be
broken, a programmable module can be inserted and be used to define a
new transfer function as shown below. |
| ..... |
|
INPUT
PROCESSING
|
> TO >
|
TRANSFER
FUNCTION
MODULE
|
> TO >
|
OUTPUT
PROCESSING
|
| ..... |
| A transfer function is defined and a program written
for it. These program modules can either be obtained pre-written for
standard features such as A-B, or written for a specific requirement.
These pre-written functions are available from a library of modules on
our TFML web page, hence the name Transfer Function Module Library. |
| TFMLs Currently
Available |
 | Rate of change limiter
| Peak Pick/Hold
| Valley Pick/Hold
| (A+B)/2
| A-B
| Totalizer with relay pulse output
| PID function block
| Sensor Validation
Please contact the Sales Office for details of other custom
macros. New ones are being added all the time. |
| | | | | | |
|
| GRAPHIC HERE - Later |
About Remote I/O
Modbus
Modbus is a master-Slave protocol. This means all communications are
initiated by the Master device (ex. Computer, PLC, DCS) and in general
the Master communicates with one Slave device (ex. MEDACS
II) at a time.
The RS485 mode determines the way that the network is connected
together. The MEDACS II can be
configured in either the 2-wire or 4-wire mode shown above. The 2-wire
arrangement has both transmit and receive signals. In comparison, the
2-wire mode makes the most efficient use of wire and connections while
the 4-wire mode has the advantage of not relying on critical timing
from the Master device.
The MEDACS II further
simplifies installation of either a 2-wire or 4-wire system by using a
unique Bus Jumper system which eliminates both the typical RS485 and
power wiring from unit to unit.
Multi-Drop and Device Addresses
The MEDACS II comes standard with one-to-one RS485 communications
which allows the Master to be wired to and communicate with one Slave.
With optional Multi-Drop Communications, the Master can be
connected to and communicate with up to 32 Salves. This allows the
Master to identify, transmit and receive information from each
specific slave.
Gateways
Although each unit is equipped with an RS485 serial interface which
can connect directly to a Modbus network, up to 64 channels can be
connected to a gateway module. Gateways provide the physical layer and
protocol conversion to common communication bus systems such as
Ethernet, Profibus, Foundation Fieldbus etc.
Contact the Sales Office for details about Gateways and their
current availability.
|
| .... |
| GRAPHIC HERE - Later |
About OPC
Managed by the OPC Foundation, OPC (Object linking and embedding for
Process Control) is an industry standard created with the
collaboration of a number of leading worldwide automation and
hardware/software suppliers working in cooperation with Microsoft. The
MEDACS II is designed to meet
the OPC requirements.
The goal of this standard "Plug-and-Play". By using the
standard OPC client-server model, any OPC-compliant device (like the
MEDACS II) will quickly,
easily and seamlessly connect to another and immediately work without
the need for lengthy installation procedures. The user can then
concentrate more on the chosen client software package (e.g. DCDS,
SCADA, HMI, Plant Scheduling) rather than the problems of system
integration.
The application of the OPC standard interface makes possible
interoperability between automation/control applications, field
system/devices and business/office applications.
Hardware Platform
The minimum hardware requirement to run OPC are IBM compatible PC:
|
P100 processor or higher
64Mb Ram
200Mb free disk space
Microsoft Windows
95 (SR2) / 98 / NT4 / 2000
|
|
SELF DOCUMENTATION
Thanks to the digital nature of MEDACS II
transmitters, self-documentation (not feasible with earlier analog
transmitters) becomes possible. In addition to the standard
configuration data stored within the transmitter, are data related to
the instrument itself such as Manufacturer, Part No., Serial No.
,Software Revision No., Date (which can be used to advise when
re-calibration is required), Final Assembly No. and Sensor Serial No.
A 32 character message facility enables additional information, such
as the name of the engineer who last serviced the instrument, to be
recorded within the instrument itself.
By using the appropriate software tools, a
complete device history can be maintained automatically thus ensuring
cost savings and reduced downtime due to better programming
maintenance.
|
INPUT SPECIFICATION @ 68 °F
| Universal
Input Overview |
| .....Sensor |
.....Range |
| .....mA |
.....4-20,
±20, ±10 |
| .....RTD |
.....Pt100,
Ni120 |
| .....T/C |
.....K,
J, T, R, S, E, N, F, B |
| .....Volts |
.....±0.1,
±10, ±5, 1-5 |
| |
| Current
Input |
| Base
Accuracy |
0.05%
FS ±0.05% of reading |
| Thermal
drift |
300ppm/°F |
| Input
impedance |
20Ω |
| Linearization |
Linear,
Square root, Power 3/2, Power 5/2, Custom |
| Two
isolated and regulated 19V power supplies are available to power the
current loops, and are capable of sourcing 24mA for each channel. |
| |
| RTD
Inputs |
| Sensor
Range |
-328
to 1,562°F |
| Linearization |
BS
EN 50751 / JISC 1604 / Custom |
| Basic
accuracy |
0.2°F
±0.05% of reading |
| Thermal
drift (zero) |
±0.006Ω
/°F |
| Thermal
drift (span) |
200ppm
/°F |
| Excitation
current |
300mA
to 550mA |
| Lead
resistance effect |
0.004°F/Ω |
| Max.
lead resistance |
50Ω/leg |
| |
|
| Thermocouple
Inputs |
|
| Type |
Range
(°F)
|
| ......K |
-328°F
|
to |
2,498°F |
|
| ......J |
-328°F
|
to |
2,192°F |
|
| ......T |
-328°F
|
to |
752°F |
|
| ......R1 |
-15°F
|
to |
3,200°F |
|
| ......S1 |
-15°F
|
to |
3,200°F |
|
| ......E |
-328°F
|
to |
1,832°F |
|
| ......F |
-148°F
|
to |
1,112°F |
|
| ......N |
-292°F
|
to |
2,306°F |
|
| ......B2 |
-15°F
|
to |
3,002°F |
|
| Custom |
-1,999
|
to |
9999 |
|
| Accuracy |
±0.04% FS ±0.04%
of reading
or ±0.5°F, whichever is greater
|
| Linearization |
BS4937 / IEC
584-3 / Custom
|
| Cold
junction error |
±0.050°F
|
| Cold
junction tracking |
0.1°F/°F
|
| Cold
junction range |
-4°F to 158°F
|
| Thermal
drift |
zero
6µV/°F
|
|
span
300PPM°F
|
| Notes:
1. Accuracy true for 1,472°F
to 3,200°F 2. Accuracy true for 752°F
to 3,002°F |
| |
|
| Voltage
Inputs |
|
|
Range
|
±10mV, ±5V,
±10V, 1-5V
|
|
Accuracy
|
0.04% FS ±0.04%
of reading
|
|
Thermal
drift
|
330ppm/°F
|
|
Input
impedance
|
1MΩ
|
|
Linearization
|
Linear,
Square root, Power 3/2, Power 5/2, Custom
|
| |
|
| Frequency
Inputs |
|
| A
wide range of input types and frequencies can be accommodated without
the need for Switches or Jumpers. Totalize functions can be achieved
via TFML. |
|
Input
Types
|
Namur, Low
Voltage (>10mV), TTL, Open Collector, PFC
|
|
Frequency
range
|
0.1Hz to
10KHz
|
|
Accuracy
|
0.003% FS
|
| |
|
| Digital
Inputs |
|
| Single
channel units can also accept two external digital inputs which can be
TTL, Open Collector, 24VDC Logic or Potential Free Contacts. Dig 1 is
dedicated to a reset/clear function enabled by the configuration
software while Dig 2 is reserved for use with TFML. Both digitals can
be read via the communications and used to signal events. |
OUTPUT SPECIFICATION
@ 68 °F
| Two
output option types are available per channel, relay or current
retransmission. The configuration of these will vary depending upon
whether they are fitted on the single or dual channel transmitter. |
| .Current
Retransmission Outputs |
| .Output
Range |
| .Single
Channel |
.0-10,
0-20, 4-20mA source or sink |
| .Dual
Channel |
.4-20mA
sink |
| .Maximum
current output |
.<23mA |
| .Accuracy |
.0.07%
or 5µA, whichever is greater |
| .Max.
power supply |
.30V
(In SINK mode) |
| .Temperature
stability |
.8µA/°F |
| Note:
Max. source load 750R |
| |
| Relay
Outputs |
| Two
relay options are available, either a single changeover or twin
independent relays with Normally closed contacts.1 |
| Alarm
Action |
Off,
High, Low, Deviation, Test |
| Hysteresis |
Programmable
0 to 100% |
| Delay
Time2 |
Programmable |
| Start-up
Delay |
Programmable |
| |
......AC |
......DC |
| Max.
switching voltage |
48V
RMS |
48V |
| Max.
current |
1A
@ 48V |
1A
@ 30V |
| Max.
power |
60VA |
30W |
| Contact
resistance |
<100mΩ |
| Electrical
life @ full load |
100,000
operations |
| Mechanical
life |
10,000,000
operations |
| Notes: |
- Contacts are Normally Closed i.e. the contact is
closed at power off and when operating in an alarm condition. The
contact opens in the absence of an alarm condition. The active
function can be reversed in the software.
- Alarms must be continuously present for this
period in order to be recognized.
|
GENERAL SPECIFICATION
| Response Time |
300mSec
|
| Filter |
Programmable or Adaptive
|
| Power Requirements |
24V DC ±10%
@ 200 mA
|
| Isolation |
500V AC I/P-O/P-PSU
|
| Ambient operating range |
-22 to 140°F
|
| Ambient storage |
-58 to 185°F
|
| Ambient humidity |
10 to 90% RH
|
| EMC emissions |
BS EN50081-1
|
| EMC immunity |
BS EN50082-2
|
| Display Range |
-1999 TO 9999
|
SERIAL COMMUNICATIONS
| Each MEDACS 2000 module comes supplied with
RS485 serial communications using MODBUS rtu protocol as standard: |
| Baud
rate |
19.2KB,
9.6KB or 1.2KB |
| Mode |
2-wire
or 4-wire available |
| Device
Address |
Network
unique address 1-255 |
|
Note: Maximum device
number for Modbus is 247.
|
ORDER CODE
MEDACS XX / Outputs / Multi-Drop Comms
| .Model
& Input Code |
....MEDACS
21
... ..One Universal Input
(with Display, Keys & 2 discrete inputs)
.MEDACS 22
... ..Two Universal
Inputs
.MEDACS 23
... ..One Frequency Input
(with Display, Keys & 2 discrete inputs)
.MEDACS 24
... ..Two Frequency Inputs |
| .Outputs
Code |
Output 1
|
Output 2
|
| 00 |
|
None |
None |
| 11 |
(not available on MED 21 & MED 23) |
Current |
Current |
| 13 |
(not available on MED 24) |
Current |
Twin
N/C |
| 22 |
|
C/O Relay |
C/O
Relay |
| 33 |
|
Twin
N/C |
Twin
N/C |
| .Modbus
Multi-Drop Serial Communications Option Code |
| 00 |
..........Standard
One-to-One RS485 Serial Communications |
| MD |
..........Modbus
Multi-Drop RS485 Serial Communications Upgrade
..........(Including M-Config and CD
Manual) |
ADDITIONAL ITEMS
| M-Config Configuration Software on CD with Manual |
| M-Config Configuration Software and Manual from Web
Site |
| M-OPC OPC Server Software |
INTRINSICALLY SAFE
APPROVED UNITS - Agency Approvals Pending
|
