Thyracont VSH88D, Operating Instructions Manual

Page: 46 / 56

46
vsh-de-130326
4.7 Switchpoints
The VSH provides 2 independent, potential-free relay switchpoints. These are
available as change-over switches at the connector according to the pin
assignmentals described in chapter 3.3.2.
The switches are active below the corresponding pressure setpoints. The control
LEDs at the connector side of the VSH are on then. The hysteresis is fixed to
30% from the setpoint value.
The programming of both setpoints is done via RS485 interface.
Address Code Data cks CR
Address:
3 Bytes, decimal; address space RS485: 001 – 999
Code: "S" for reading, "s" for writing setpoints
Data: Query to read or unlock: 1 Byte; "1" for setpoint 1 / relay A,
"2" for setpoint 2 / relay B
Read or write setpoint: 6 Byte; float
cks: 1 Byte, checksum, defined as sum over all Bytes of the fields
address, code and data, modulo 64 plus 64.
CR: Carriage Return (0Dh, 13d)
Example (for address-switch in position "1"):
Action Telegram to
transducer Answer telegram
from transducer
Read setpoint 2
"001S2V
C
R
" "001S400016O
C
R
"
( 4.0x10-4 mbar)
Unlock setpoint 2
Set setpoint 2 to
4.2x10-4 mbar "001s2v
C
R
"
"001s420016q
C
R
"
"001s2v
C
R
"
"001s420016q
C
R
"
Please find further information about the Thyracont communication protocol in
chapter 4.2.