10
The parameters presented on PAGE-10 depend upon the type of algorithm selected for the control purpose, viz., On-Off,
Pulsed On-Off and PID. The parameter list further extends if the selected control mode is bi-directional (that is, heat-cool
control). Refer Table 4.1 for the parameter descriptions and settings.
CONTROL PARAMETERS
Table 4.1
Section 4
0 to 250 Seconds
(Default : 25 sec.)
0 to 1000 Seconds
(Default : 100 sec.)
0 to 999 Units
(Default : 50 units)
Parameter Description
Settings
(Default Value)
PROPORTIONAL BAND
(Available for PID Control only)
Sets proportional gain (% power per unit error). Defined in same
units and resolution as that for PV.
INTEGRAL TIME
(Available for PID Control only)
Sets integral time constant in seconds. Setting the value to 0, cuts-
off the integral action.
DERIVATIVE TIME
(Available for PID Control only)
Sets derivative time constant in seconds. Setting the value to 0,
cuts-off the derivative action.
0.5 to 120.0 Seconds
(in steps of 0.5 secs.)
(Default : 20.0 sec.)
CYCLE TIME
(Available for PID Control only)
Sets the total ‘On + Off’ time in seconds for time proportional
power output through OP1 Relay / SSR.
0.1 to 10.0
(Default : 1.0)
RELATIVE COOL GAIN
(Available for PID Control with bi-directional, that is, Heat-Cool
mode)
Sets the ratio of cooling power to the heating power.
COOL CYCLE TIME
(Available for PID Control with bi-directional, that is, Heat-Cool
mode)
Sets the On + Off cycle time in seconds for time proportional
power output through OP2 Relay / SSR.
0.5 to 120.0 Seconds
(in steps of 0.5 secs.)
(Default : 20.0 sec.)
HYSTERESIS
(Available for On-Off or Pulsed On-Off Control only)
Sets differential (dead) band between On-Off switching for OP1.
1 to 999
(Default : 2)
HEAT POWER LOW
(Available for PID Control only)
Sets the minimum % output power limit for OP1.
0 to Power High
(Default : 0)
Visit www.ppiindia.net. Refer technical notes on CONTROL and TUNING for detailed understanding of the
parameters / terminologies used for describing control parameters in this section.
