
LAUDA Ultra-Thermostats
UB 20(-D), UB 25, UB 50, UB 30, UB 40
UB 20 F, UB 20 J, UB 30 J, UB 40 J, UB 65 J
UB 20 JL, UB 30 JL, UB 40 JL
YATE0013 /10.04.02
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7.
Status signal
8.
Read-out of the control parameter and transfer
9.
External controller status and start
9.14.2 General
principles
The interface operates with two stop bits, no parity bit and with 8 data bits. The transfer
rate can be set to 4800 baud or 9600 baud (see Item 9.4.6).
Values from the computer can be transferred directly to the thermostat, i.e. transmitted,
e.g. OUT, SEG and START commands, or data can be transmitted from the thermostat
to the computer on request with an IN command. An OUT, SEG or START command, if
transmitted correctly, is always acknowledged by the thermostat with the message "OK"
followed by LF and CR.
This message, like any other response, has to be requested by the computer!
Any output command (OUT, SEG, START, STOP) switches the thermostat to remote
operation. This can be recognized by an R (setpoint source RS 232) on the right in L
2
.
Then all the keys are locked except for the functions "SHIFT
" and "SHIFT
".
If there is no output instruction from the connected computer the keyboard can be
activated until the next output instruction by pressing the keys
.
The data requests by the thermostat (IN commands) only lock the programme keys
"SHIFT
" and "SHIFT
". All the other key functions are in operation.
In the following text the symbol "_" will be taken to mean blank (no character).
RS 232 interface and controller are operated by a single processor; for optimum control
it is therefore advisable to have pauses of at least 100 msec between the interface
commands.
9.14.3 Output
commands
OUT_XXX.XX
Setpoint transfer with up to 3 places before the decimal point
and up to 3 places behind. This includes the negative sign.
Transfer can take various forms, e.g. for 5.00°C: 005.00, 05,
05.0, 005, 5.00.
A BASIC programme for the IBM PC which can be used to transfer any values between
the set upper limit (see Item 9.3.4) and which displays the response "O.K." or a possible
error message, may be as follows: