use programmable controllers which are manufactured by Watlow
Watlow Comm7 Utility
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. NOTE: Comm7 will only work on Windows 95 through XP. It will NOT work on Windows 7 or 8.
Visual Basic Programming
Examples from Watlow
Example of Communications in Modbus RTU Using Visual Basic, WatlowMB.zip (23KB).
illustrates sample 16-bit Modbus packets to write a temperature set point
and read the actual temperature.
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.
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
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.
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.
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) .
- 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