West Control Solutions 8700+ - Manual (Page 63)

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Page 58
P6100, P8100 & P4100 Model Group 59305, Issue 7 – March 2014
P6100, P8100 & P4100 Controllers
–Communications Parameters
The Modbus parameter addresses, and the possible ASCII message types and parameter
indents for the P6100, P8100 & P4100 are detailed below. RO indicates a parameter is read
only, R/W indicates it can also be written to. Communications writes will not implemented if
the Communications Write Parameter is disabled. Refer to the Modbus and ASCII
Communications sections of this manual for details of the protocols used.
Bit Parameters
Bit parameters are not applicable to the ASCII protocol.
Table 14. P6100, P8100 & P4100 Communications - Bit Parameters
Parameter Modbus
Parameter No.
Notes
Communication
Write Status 1 RO 1 = Write Enabled, 0 = Write Disabled. A negative
acknowledgement (exception code 3) is sent to write
commands if communications writes are disabled
Auto / Manual 2 R/W 1 = Manual Control, 0 = Automatic Control
Self Tune 3 R/W 1 = Activate(d), 0 = Dis-engage(d)
Pre tune 4 R/W 1 = Activate(d), 0 = Dis-engage(d)
Alarm 1 Status 5 RO 1 = Active, 0 = Inactive
Alarm 2 Status 6 RO 1 = Active, 0 = Inactive
Setpoint Ramping 7 R/W 1 = Enable(d), 0 = Disable(d)
Loop Alarm Status 10 R/W 1 = Active/Enable, 0 = Inactive/Disable
Loop Alarm 12 R/W Read to get loop alarm status. Write 0/1 to
disable/enable.
Digital Input 2 13 RO State of Option B digital input.
To set the bit value to 1 write FF, to set the bit value to 0 write 00. Refer to Function Code 05 in the
Modbus Communications section.
Word Parameters
Table 15. P6100, P8100 & P4100 Communications - Word Parameters
Parameter Modbus
Parameter No.
ASCII Ident &
Message Types
Notes
Process Variable 1 RO M
Type 2 RO
Current value of PV.
If under-range = 62976 (<??>5 ASCII)
If over-range = 63232 (<??>0 ASCII)
If Sensor break = 63488 (ASCII = n/a)
Setpoint 2 R/W S
Type 2
Type 3/4
RO
R/W
Value of currently selected setpoint.
(Target setpoint if ramping).
Parameter is read only if the current
setpoint is RSP.
Output Power 3 R/W W
Type 2
Type 3/4
RO
R/W
0% to 100% for single output;

100%
to +100% for dual output control.
Read Only if not in manual control.
Deviation 4 RO V
Type 2 RO
Difference between Process Variable
and Setpoint (value = PV-SP)