Micromod MOD: 30ML Operation and Template Setup - Manual (Page 47)

MOD 30ML Multiloop Controller
OPERATION
3-15
Transfers In A Loop with Automatic Reset
When the control algorithm has reset (integral) response, transfers from automatic to manual
and from manual to automatic are always bumpless. After switching from manual to
automatic, the process variable is under automatic control in response to the active set-point,
either local or remote.
If the control loop is configured for local set-point tracking, the local set-point tracks the
process value when the loop is in manual. The process is always at the local set-point when a
transfer to automatic is made, regardless of set-point limits
If the control loop does not have local set-point tracking, the local set-point and the process
variable may not be at the same value at the time of a transfer from manual to automatic. The
transfer is still bumpless, but immediately after the transfer the process ramps toward the
local set-point value at the reset rate.
Transfers In A Loop with Manual Reset
If the control loop does not have automatic reset (integral) response, any set-point/process
offset at the time of a transfer from manual to automatic is maintained. If the loop is
configured to provide procedureless manual reset, the manual reset value required to
eliminate the offset is automatically calculated while the loop is in manual, and this calculated
value is used to remove the offset following a transfer to automatic.
If the loop does not have procedureless manual reset, a set-point/process offset after transfer
to automatic can be eliminated by adjusting the manual reset value. This value is one of the
tunable parameters available for adjustment in the tune sequence. Access the tuning
sequence and adjust manual reset to the required value as described in Section 3.14
Tuning.