IKA RET Control-Visc Mode D'emploi page 31

Serial RS 232 interface and USB
USB interface
The Universal Serial Bus (USB) is a serial bus for connecting the
device to the PC. Equipped with USB devices can be connected to
a PC during operation (hot plugging). Connected devices and their
properties are automatically recognized. Use the USB interface in
conjunction with labworldsoft
and also to update the firmware.
Installation
First, download the latest driver for IKA devices with USB interface
from http://www.ika.com/ika/lws/download/usb-driver.zip and in-
stall the driver by running the setup file. Then connect the IKA
device through the USB data cable to the PC. The data communi-
cation is via a virtual COM port. Configuration, command syntax
and commands of the virtual COM ports are as described in RS
232 interface.
Configuration
The RS 232 serial interface can be used to operate the device using
a computer and a suitable user program (labworldsoft).
In order to increase safety when operating the RET using a
PC, a watchdog function can be activated which monitors
the continuous data flow (see section entitled: "Watchdog
function").
• The functions of the interface circuit between the laboratory
device and the automation system are a selection from the
signals specified in the EIA standard RS232 as per DIN 66020
Part 1. The assignment of the different signals can be seen in
the image.
• Standard RS 232, corresponding to DIN 66259 Part 1 is valid
for the electronic characteristics of the interface circuits and
assignment of signal states.
• Transmission process: asynchronous character transmission in
start-stop operation.
• Transmission type: full duplex
• Character format: character composition according to data
format in DIN 66022 for start-stop operation. 1 start bit,
7 character bits, 1 parity bit (even), 1 stop bit.
• Transmission speed: 9,600 bit/s
• Data flow control: hardware handshake RTS/CTS
RTS: (PIN 7) LOW (positive voltage)
/ COMPUTER can transmit
RTS: (PIN 7) HIGH (negative voltage)
/ COMPUTER cannot transmit
NAMUR commands
IN_NAME
IN_PV_X X=1;2;3;4;5;7;80;90 Current value reading
IN_SOFTWARE
IN_SP_X X=1;2;3;4;7;8;12;
42;54;55;56;
IN_TYPE
OUT_NAME name
OUT_SP_12@n
OUT_SP_42@n
OUT_SP_X n X=1;2;4;7;
54;55;56
® for operation in "Remote" mode
Function
Title request
Software ID number, date, version request
Set target value reading
Lab device identification request
Output of identification name. (Max. 6 characters; default: IKARET)
Setting WD safety limit temperature with set value echo
Setting WD safety limit speed with set value echo
Setting of target value to n
CTS: (PIN 8) LOW (positive voltage)
CTS: (PIN 8) HIGH (negative voltage)
• Access method: data transmission from the device to the
computer only occurs after a request from the computer.
Command syntax
The following points should be noted for the instruction set:
• Commands are generally sent from the computer (master) to
the lab device (slave).
• The lab device only responds to requests from the computer.
• Commands and parameters, as well as consecutive parameters,
must be separated by at least o n e space (code: hex 0x20).
• Each individual command including parameters and data and
all responses are completed with CR LF (code: hex 0x0D and
0x0A) and can have a maximum length of 10 characters.
• The dot is used for decimal separators in a floating-point value
(code: hex 0x2E).
The details given above generally comply with the recommendations
of NAMUR (NAMUR recommendations for the design of electrical
plug-in connectors for analogue and digital signals in laboratory
MSR devices. Rev. 1.1).
Summary of available NAMUR commands
Abbreviations used:
X,y = numbering parameter (integer)
m = variable value, integer
n = variable value, floating-point number
X = 1 medium temperature(external temperature sensor)
X = 2 hot plate temperature
X = 3 hot plate safety temperature
X = 4 speed
X = 5 viscosity trend
X = 7 heat transfer medium temperature
X = 80 pH value
X = 90 Weight value
X = 54 Error 5 response time in seconds (180 <= n <= 1200)
X = 55 Intermittent mode cycle time in seconds
X = 56 Intermittent mode, duration of interruption in seconds
/ COMPUTER ready-to-receive
/ COMPUTER not ready-to-receive
( 10 <= n <= 600 )
( 5 <= n <= 60 )
Display
(additional)
31