Vemer FHT Series User Manual page 8

No output is activated within
the dead band; outside
the dead band the device
operates by direct action
if the parameter controlled
increases and by reverse
action if it decreases.
PWM operating mode
(time-controlled proportionate)
• Dead-band operation
featuring relays activated
periodically by impulse
(settable timing, see Output
menu).
The PWM mode modulates
the power based on the
position of the parameter
within the differential (power
increases as deviation from
set-point increases).
Warning: Not recommended for use with compressors, as this would cause
short start/stop periods.
Direct operating mode [PRO=0]
• When in this mode, all outputs
operate in direct.
Set-point 1 [ST1] and
differential 1 [DF1] must be
assigned values.
Hysteresis is to the right of
the set-point.
If both outputs are used, the
hysteresis of each output is
equal to half of the differential.
In this case output 1 will turn on when the parameter measured reaches value
[ST1]+[DF1]/2; output 2 will turn off on reaching this value.
Reverse
operating mode [PRO=1]
• When in this mode, all outputs
operate in reverse.
Set-point 1 [ST1] and
differential 1 [DF1] must be
assigned values.
Hysteresis is to the left of the
set-point.
ON
OFF
Set - Diff (R) - ZN
ON
OFF
Set - Diff (R) - ZN
OUT 1
ON
D
OFF
Diff. 1
Set 1
1 output
OUT 1
ON
R
OFF
Diff. 1
Set 1
1 output
- 34 -
User Manual – Thermoregulator FHT
Dead band Mode
R
ZN ZN
Set
Temperature
PWM Mode
ZN ZN
R
Set
Temperature
Mode PRO=0
OUT 1
ON
D
OFF
Set 1
2 outputs
Mode PRO=1
OUT 2
ON
R
OFF
2 outputs
D
Set + Diff (D) + ZN
D
Set + Diff (D) + ZN
OUT 2
D
Diff. 1
OUT 1
R
Diff. 1
Set 1