CAL Controls CALCOMMS 3300 User guide

Application Guide for Installation and
Cabling of the
Communications Option for
CAL 3300 / 9300 / 9400 / 9500 Controllers
8th November 1999
Ver 1.10
Doc: 33010 Iss: 005

Introduction
The 3300 / 9300 / 9400 / 9500 series controllers can all be
ordered or retrofitted with either an RS232 or RS485 serial
communications interface board. If the controller has the
communications interface fitted then skip to the section
titled Installation/Cabling.
Feature RS232 RS485
Type of transmission lines Unbalanced Differential
Maximum number of drivers 1 128
Maximum number of receivers 1 128
Maximum cable length 15m 1200m
Maximum data rate 19.2Kb/sec 19.2Kb/sec
Maximum CMV +/- 25V +12 to -7V
Table lists the features of both RS232 and RS485 standards.
Cable: To ensure data integrity over long transmission
distances, it is recommended that good quality RS485 cable
is used.
Recommended: RS485: Belden 9841, RS232: Belden 9501
available from most leading distributors, and stocked by
CAL.
2
FITTING A COMMUNICATIONS INTERFACE BOARD
The RS232 and RS485 interface boards are interchangeable
and are fitted in exactly the same way, please read the fitting
and safety instructions before proceeding.
Caution: Live circuits can hold charge for short
periods after isolation from the voltage supply.
Electrostatic precautions should be observed
when handling the controller outside the sleeve.
After isolating the controller from it’s supply, the controller
front bezel and circuit board assembly can be unplugged
from the sleeve. Grasp the bezel firmly by the recesses on
each side and pull. A screwdriver can be used as a lever if
required.
To fit the RS232 or RS485 interface you will require the
following parts, which are supplied with the interface.
Nylon Full Nut
Code – 082-042
Brass Half Nut
Code – 082-041
Nylon Screw
Code – 082-028
Nylon Spacer
Code – 082-012

Insert the Nylon Screw into the 3mm diameter hole
at the bottom left hand corner of the 3300 / 9300 /
9400 / 9500 board.
Place spacer over Nylon screw thread.
Screw the Nylon Full Nut onto the screw.
Do not overtighten as this will damage the screw
thread.
Plug the 5-way female connector on the Comms
Board into the 5-way male connector on the
Controller board ensuring that connectors are all in
alignment. At the same time ensure the hole in the
Comms board fits over the screw thread.
Screw the Brass Half Nut onto the Comms board.
Do not overtighten but ensure it’s tight enough to
stop the board from moving.
Cut the top of the screw thread so that it is level
with the top of the Brass Half Nut.
3
Now you are ready to refit the Controller into
its case. To do this carefully slide the PCB into
the case aligning it with the connector arms
at the rear, and then press the bezel
assembly firmly into the sleeve until the latch
clicks in order to compress the gasket and
seal to NEMA4/IP66.
Diagram 1

RS485 CONNECTIONS
RS485 is a half duplex serial communications link and is the
standard most commonly used for industrial applications due
to it’s high noise immunity and multi-drop capability. It
enables a PC to communicate with up to 128 instruments
over distances up to 1200 metres, and requires the addition
of an RS485 interface card, or a separate RS232 / 485
converter.
Installation / Cabling
RS232 CONNECTIONS
RS232 is the standard most widely used for interfacing
peripherals to PC’s and is designed for serial communications
with single instrument up to distances of 15 metres, in a low
electrical noise environment.
Connection is via a screened two core cable where the
voltage signal on each line is referenced to the screen which
is grounded. Most PC’s have one or two RS232 compatible
ports fitted as standard.
4
1 2 3 4 5 6 7 8
910 11 12 13 14 15 16
3300/9300
rear terminal
15
69
PC Com Port
DB-9 Pin
Tx
Rx
Gnd
Tx Rx (+)
1 2 3 4 5 6 7 8
9 10 11 12 13 14 15 16
To
additional
units
1 2 3 4 5 6 7 8
9 10 11 12 13 14 15 16
3300/9300
unit 2
Tx Rx (-)
3300/9300
unit 1
Gnd
Tx Rx (+)
Tx Rx (-)
Gnd
Connections if PC 485 card used
To
RS 485
interface
Diagram 2 Diagram 3

Each RS485 interface has specific connection and
termination biasing requirements which will be
detailed in their installation instructions. The general
principals are as follows.
Terminations Because each wire is a transmission line,
it must be properly terminated to prevent reflections.
Where multiple instruments are daisy-chained
together, a 120 ohm terminating resistor should be
fitted at the connection to the PC and to the last
instrument in the chain.
Bias Resistors When transmission lines are not
transmitting, they remain in an indeterminate state
which can allow receivers to receive invalid data bits
due to electrical noise on the cable. To prevent this,
the lines should be forced into a known state by
fitting two 620 ohm bias resistors to one point
(node).
If an RS485 interface card is being fitted to the PC,
separate bias resistors may not be needed because
they may already be fitted to the card. Check the
manufacturers specification.
As mentioned earlier RS485 cards and converters
differ greatly in their requirements and therefore the
installation instructions supplied with the interface
should be read carefully. 5
–
Tx
Rx +
+
–
+
–+
–
Tx Rx +
–+
–
Tx Rx +
–+
–
Tx Rx
Instrument 1 Instrument 2 Instrument ‘N’
+5V 620Ω
0V 620Ω
–
120Ω
Tx
Rx +
+
–
+
–+
–
Tx Rx +
–+
–
Tx Rx +
–+
–
Tx Rx
120Ω
Instrument 1 Instrument 2 Instrument ‘N’
Diagram 4 Termination resistors
Diagram 5 Bias resistors

We recommend that before you proceed further you check
that there is sufficient power derived from the serial port to
drive all the connected controllers. The power you can
derive from PC serial ports varies greatly from PC to PC, and
the amount of power needed to run the RS485 bus varies
according to the length of the cable, the number of
instruments connected, and the biasing requirements.
To check whether there is sufficient power measure the
voltage present on pin 9 of the ‘D’ connector relative to
ground. This must be at least 5.5V at all times. It is important
to measure the voltage on pin 9 with all the controllers
connected. If the power derived from the serial port is
insufficient, an external power supply can be connected to
pin 9 of the connector.
The details above are general requirements, if you are
installing more than 20–30 controllers, or more than 300m of
cable, then additional biasing and power will be required.
To fit additional biasing you need to connect two 620 Ohm
resistors externally as shown in diagram 5. This then requires
an external power supply to be fitted, this provides the
extra power for the biasing resistors, and also the power to
drive all 128 controllers over 1200 meters.
EXTERNAL POWER SUPPLY
The recommended external power supply requirements are
+5.5V to +14V and min 100mA.
6
KK SYSTEMS K485ADE
If you have purchased the KK Systems RS232/485 converter
from CAL Controls then the specific requirements for this
converter are detailed here. Please note that the KK Systems
K485ADE are only designed to work at 9600 baud rate, with
8 data bits, no parity and 1 stop bit.
Termination Resistors It is not generally possible to derive
sufficient power from a PC232 port to drive a 120Ωresistor
with RS485 voltage levels. A capacitor e.g. 1000pF should be
connected in series with any such terminator, to eliminate
the DC loading which a resistor alone would produce.
Note: The controlled slew rate driver used in this converter
makes termination at either end of the bus unnecessary for
cables shorter than approximately 300m, this assumes the
use of Belden 9841 cable.
Bias Resistors There are 2 100KΩbias resistors fitted
internally to the converter, so generally this should be
sufficient.
15
69
KK485-ADE
Tx /Rx (+)
1 2 3 4 5 6 7 8
9 10 11 12 13 14 15 16
To
additional
units
3300/9300/9400
Tx /Rx (-)
Gnd
Diagram 6

Immediately after power-up, both instrument, and PC comms
settings need to be made compatible before communication
between them is possible. Instrument defaults are shown
below together with available options.
(Address) This is a unique identification
number that must be allocated to each
instrument connected to the network.
Default = 0. Options;
1 to 247
(Baud rate) The setting determines the serial
communication data transmission rate in
bits/sec, and must match the PC settings.
Default = 9600.
Options;
1200; 2400; 4800; 9600 and 19200
NOTE: If a comms board has been retro fitted
the default baud rate is 1200.
(Data) Sets the transmission format,
and must match the PC settings
Data Format Table
Settings Start bits Data bits Parity Stop bits
Default 1 8 n (none) 1
Option 1 1 8 e (even) 1
Option 2 1 8 o (odd) 1
(Debug) Commissioning and
troubleshooting aid. Display shows when the
instrument is transmitting or receiving data by
rapidly flashing the three horizontal segments
of the first and last digit of the display.
First digit = Tx; last digit = Rx
Default = Off. Options;
off; on
Only use dbuG during commissioning or trouble-shooting
because it shares display segments and therefore corrupts
the normal display.
Instrument Comms Settings
7
!ADDR
BAUD
DATA
DBUG

Configuring Instrument Comms Settings
This should also be done immediately after power-up, and
is only possible from the instrument front panel.
On power-up the controller will display the self test
sequence followed by Alternating INPT and
nonE
Note: During the following procedure the display will revert
to alternating INPT and
nonE after 60 seconds of
keying inactivity, but will retain any settings already
completed. Should this occur, or in the event of becoming
‘lost’ in the program, please start again from the alternating
INPT and
nonE display.
To select Level C (communications settings)
Press ▼ once display alternates LEVL and 5
Press and hold ✱ and press ▼ five times to reach level C
display alternates LEVL and
C
Note: Level C is only visible when the comms interface
board is fitted to the unit
To set instrument comms address
Press ▲ once display alternates ADDR and
0
Press and hold ✱ and press ▲ to index to chosen address
number
(1 to 247)
Note: In the absence of any conflicting information the
following comms settings should be left as the default values
(see details on page 7).
To read or adjust comms settings
Baud rate
Press ▲ once display alternates BAUD and
9600
(Default setting)
Press and hold ✱ and use ▲ or ▼ keys to select preferred
value.
Data format
Press ▲ once display alternates DATA and
18n1
(Default setting)
Press and hold ✱ and use ▲ or ▼ keys to select preferred
setting. (see table page 7).
Debug setting
Press ▲ once display alternates DBUG and
oFF
(Default setting)
Press and hold ✱ and use ▲ key to select
on
To enter settings into memory
Press and hold ▲ and ▼for 3 seconds display alternates
INPT and
nonE
To check settings; repeat the above procedure
The unit is now ready to be configured from the PC.
Note: Where more than one instrument is connected to the
system, it is useful at this point to list them by location, title
and comms address. The list can then be used as a
reference to ensure that the instruments are given the same
identity when configuring the comms link from the PC.
!
8

Application Software
The controllers with the communications interface fitted use
the Modbus RTU protocol. If you wish to integrate the
controllers into a third party software application, or code
your own custom software application, there is a document
that explains how to communicate with the controllers. The
document is entitled Cal 3300/9300/9400/9500 Modbus RTU
communications guide, and is available from CAL Controls Ltd.
CALCOMMS™ APPLICATION SOFTWARE
The easiest way to communicate with the controllers is using
the dedicated CALCOMMS™ package for remote configuration
and data acquisition. This package requires no programming or
configuration and is ready to run, if you are familiar with
Windows95/98 you can be up and running in minutes.
CALCOMMS™ PC REQUIREMENTS
To gain the full benefit of CALCOMMS™ software, it is
recommended that the PC is fitted with a Pentium processor
and is running Windows95/98 or WindowsNT and has a
graphics card capable of displaying a minimum of 256 colours.
A minimum of 16Mb of RAM for Windows95/98 and 32Mb of
RAM for WindowsNT are recommended, together with enough
free hard disk space to meet your logging requirements.
CALCOMMS™ PERFORMANCE CONSIDERATIONS
When an application has more than 32 instruments on the bus,
we recommend you look at using a higher specification PC. If
you have between 32 and 128 instruments on the bus a
recommended minimum PC specification would be a Pentium
200MHz processor with 64Mb of RAM. To keep CPU and RAM
usage to a minimum it is generally good practice not to log
data more frequently than necessary, and also keep the time
base of charts as small as reasonably possible. If you need to
review the full chart history you should select ‘View Plot’ mode
and then increase the time base of the chart, remember to
return to ‘Auto Plot’ mode when finished. If possible you
should also increase the ‘Refresh Frequency’ option in the
‘Select Units To Chart’ screen. This option allows you to keep
logging data in the background, but only redraw the chart
when ‘X’ number of samples have been acquired from each
controller. For instance if the ‘Sample Frequency’ is set to 1
second and the ‘Refresh Frequency’ is set to 20, the chart will
only be redrawn and updated every 20 seconds, but logging
still continues in the background at the rate of once per
second. For more detailed information on tuning the
performance of CALCOMMS™ to your application
requirements, contact CAL Controls Ltd.
Additional information
SETTING SECURITY LEVELS IN CALCOMMS™
It should be noted that functions that have been locked
appear to be still locked even when you are logged in at the
correct security level. This means that the operator or
supervisor have permission to unlock and adjust functions
they have locked, but have to unlock that function first, then
they can adjust the function. To retain your security settings
remember to re-lock any functions you have unlocked for
adjustment. 9

CAL Controls Ltd
Bury Mead Road, Hitchin, Herts, SG5 1RT. UK
Tel: + 44 (0)1462-436161 Fax: + 44 (0)1462-451801
email: [email protected]
http://www.cal-controls.com
CAL Controls Inc
1580 S.Milwaukee Avenue, Libertyville, IL 60048. USA
Tel: [phone] Fax: [phone]
33010/5/1199