TestEquity chambers
use programmable controllers which are manufactured by Watlow
Electric.
LabVIEW Drivers
for RS-232
LabVIEW_RS232.zip (15M)
provide the ability to communicate with the Watlow F4 Controller used
on TestEquity chambers using National Instruments LabVIEW over the RS-232
interface.
These LabVIEW files
were developed for TestEquity by LabVIEWexpert.com. LabVIEWexpert.com
is a leading National Instruments Alliance Member, supplying custom
test software solutions to hundreds of customers worldwide. The company
consistently provides “Low Risk Software Solutions to High Stakes
Automation”. If you would like assistance with your LabVIEW project,
please visit them at www.LabVIEWexpert.com.
Watlow Comm7 Utility
Software
Comm7 (2.6M)
is a Windows-based diagnostic utility created by Watlow. Comm7 can be
used to upload/download controller configurations or log data to a text
file via RS-232. Included in this download are files to restore the setup
of F4 controllers back to the configuration as shipped from TestEquity.
Visual Basic Programming
Examples from Watlow
Example of Communications in Modbus RTU Using Visual Basic, WatlowMB.zip (23KB).
Watlow Data Communications
Reference
Electronic User's Manual, WatCDCE_A.pdf (522K).
(see applicable references to F4 Controller and Modbus)
Sample 16-bit
Modbus Packet
Modbus_Packet.pdf (209K)
illustrates sample 16-bit Modbus packets to write a temperature set point
and read the actual temperature.
RS-232 Troubleshooting
Tips for TestEquity Chambers
We receive many calls
each week regarding RS-232 communication issues. There are several
issues which must be addressed in order to communicate successfully
with the chamber. With thousands of chambers in the field, we have
never had a verified case of a bad serial interface in the controller.
Below are several of the most common communication issues.
Are you
using the correct cable?
The DB-9 connector is wired to accommodate a null-modem cable. A null-modem
cable has pins 2 and 3 swapped on each end. You CANNOT use a straight
through cable.
Is the baud
rate set correctly?
All TestEquity chambers
shipped since mid-2003 have the baud rate set at 9600. Older chambers
have the baud rate set at 19200. The baud rate of the controller MUST
match the baud rate in your communications program. The baud rate is
changed in the controller's Go to Setup\Communications menu. You may
require a password to enter the Setup menu. If so, call TestEquity to
get the password.
Does your
software communicate using the Modbus RTU protocol?
To communicate with
the controller from a PC, you need to run software that uses the Modbus
RTU protocol. You CANNOT use Hyperterminal.
Modbus Registers
Each controller
function has a "register" number which can be read or written to (when
applicable). These registers are listed Chapter Seven of the Series
F4 User's Manual (pdf, 4M) .
Common Modbus
Registers
- The actual chamber
temperature reading is Modbus register 100 (Input 1 Value).
- The static temperature
set point is Modbus register 300 (Set Point 1).
- The temperature
set point during a profile is Modbus register 4122 (Set Point 1,
Current Profile Status).
- The decimal points
are implied. For example, 1005 is actually 100.5 and -230 is -23.0.
- The Digital Output
1 (Event 1) function is Modbus register is 2000
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