1-RELAY PROCESS 4-20 mA LOOP INDICATOR / MONITOR / WINDOW COMPARATOR OVER / UNDER PROTECTION with 24V power supply ( to power external loop)


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The input signal is converted and displayed as real-world values with up to 3 decimal places.
Maximum & Minimum values are logged for 24 hours (updated every 60 min).
By default the re-transmittion parameters are set so that the output follows the input.
By setting the Span to a negative value, the device can be used as an inverter, generating a decreasing output signal as the input increases.
Other features include user programmable signal damping & all settings may be locked & code protected to avoid changes from being made by unauthorised personnel 


The signal is displayed as ‘real world’ values.(eg 0-100°C ,not 4 -20mA).
By setting the span to a negative value, the display will indicate lower values as the input rises.
The relay remains energised while the input signal is between the upper and lower set points.
Once de-energised, the signal must change in the opposite direction by the hysteresis amount before the relay will reenergise.
Note: the relay will NOT re-energise while the latch pins are shorted. The latch pins can also be used as a reset.



  • monitor for "OVER"/"UNDER" value conditions
  • independantly reverse relay(s) action (energise or de energise when fault occurs)
  • adjustable hysteresis (differential)
  • negative span values allows display to reduce in value as input increases (eg 100%=4mA, 0% = 20mA)
  • adjustable resolution, by adjusting decimal point
  • seperate upper and lower set points allows the device to be set for OVER, UNDER or WINDOW COMPARATOR monitoring
  • adjustable "START UP" delay, allows input to stabalize at power up before monitoring starts
  • adjustable "TRIP" delay (reaction delay) allows fault conditions for short period of time
  • activate the "LATCH" facility independantly for each relay (use one relay to control, and another to latch alarm conditions)
  • adjustable calibration facility allows the user to improve overall system accuracy (compensate for transducer inaccuracy)
  • keypad lock with 4-digit code
  • re transmit the signal (or any part thereof) as 4-20mA, set re transmit offset and span to any value within the display scale.


DISPLAY OFFSET:                    -999 to 9999

DISPLAY SPAN:                       -1999 to 9999

DISPLAY RESOLUTION:           0.01 to 1.000 (adjustable)

INPUT OFFSET:                        0 to 20.6mA

INPUT SPAN:                           0 to 20.6mA

24V DC supply current limit (-P devices only): 23mA


RESPONSE TIME:                     <1-4sec


Display offset:                -999 to 9999

Display span:                  -1999 to 9999

Display resolution:          0.01 to 1.000  (adjustable)

Input offset:                    0 to 20.3V

Input span:                      0 to 20.3V (offset + span maximum = 20.3V)

Measurement resolution: 20 uA

Accuracy                          ±0.3% @ 25°C (% of full scale)

Input voltage:                 ±15% of rated input