Alarms, Amplifiers, and Transmitters for Strain Gauge, Bridge, Pressure Transducer or Sensor, Load Cell Applications

lifetime warranty
  • Lifetime Warranty on API Modules
  • LoopTracker® I/O LEDs
  • Hot-Swappable Plug-In Design
  • Zero and Span Xmtr Output Calibration
  • Push to Test Output
  • Full I/O/Power Isolation
Click on PDF links below
for product information

Literature and Links

API product brochure
Options & accessories
Regulatory Compliance page

Reference Info

Troubleshooting strain gauge sensors
LoopTracker and Output Test
Sink vs source
Alarm terminology
Relay protection & EMI suppression

UL Approvals

API modules USA
API modules Canada

APD modules USA
APD modules Canada

Amplifiers for

  • Load Cells
  • Weighing Systems
  • Pressure Transducers and Sensors
  • Strain Gauges
  • Wheatstone Bridges
  • Force Transducers and Sensors

Application Notes

Chemical plant
Platform scale
Truck scale
Dispensing system automation
6-Wire strain gauges
Pressure sensor vs. pressure transmitter
Pressure transducer calibration
Weighing shipping containers
Pressure system calibration
Pressure transducer calibration
Plastic extruder pressure
Extrudung guitar strings
Custom product for high speed pill presses

How to Order

  1. Select a model
  2. See data sheet for ordering info and options
  3. Note that options affect pricing
  4. Request a quote via chat or call us
  5. 2-5 day typical lead time + shipping time
  6. 5-10 day lead time for quantities of 5 or more + shipping time
  7. To place your order
Model Input/Output Features Product

Alarm Trip for 1 to 4 Sensors:

  • Load Cell
  • Pressure Transducer or Sensor
  • Strain Gauge
  • Bridge
  • Force Transducer or Sensor
Factory Configured

APD 1500  from $319
APD 1520  from $339

Open Datasheet
Download Datasheet
Strain gauge mV/V rating, mV range,
Excitation voltage
Factory configured
100 Ω to 10000 Ω strain gauge
5 mV to 2000 mV
1-10 VDC excitation
Accepts one sensor for input

APD 1500 Single Alarm Trip
Dual SPDT contact sets
Standard: HI alarm, non-latching, normal acting
See data sheet for alarm options

APD 1520 Dual Alarm Trip
2 independent SPDT contact sets
Standard: HI/LO alarms,
non-latching, normal acting
See data sheet for alarm options

  • User adjustable setpoint(s)
  • User adjustable deadband(s)
  • 8 Amp SPDT contacts
  • Input LoopTracker LED
  • Alarm status LEDs
  • Alarm options: LO, HI/HI, LO/LO, band alarm
  • Optional reverse acting
  • Optional latching alarms
  • Push to test/reset
  • Remote push to test/reset
  • Full I/O/power isolation
  • Removable plugs
  • DIN rail mount without tools
  • Universal power 85-265 VAC, 60-300 VDC
  • D option for 9-30 VDC, 10-32 VAC power

APD 1500UL approved
APD 1500, APD 1520